rfc9363.original   rfc9363.txt 
lpwan Working Group A. Minaburo Internet Engineering Task Force (IETF) A. Minaburo
Internet-Draft Acklio Request for Comments: 9363 Acklio
Intended status: Standards Track L. Toutain Category: Standards Track L. Toutain
Expires: 12 April 2023 Institut MINES TELECOM; IMT Atlantique ISSN: 2070-1721 IMT Atlantique
9 October 2022 February 2023
Data Model for Static Context Header Compression (SCHC) A YANG Data Model for Static Context Header Compression (SCHC)
draft-ietf-lpwan-schc-yang-data-model-21
Abstract Abstract
This document describes a YANG data model for the SCHC (Static This document describes a YANG data model for the Static Context
Context Header Compression) compression and fragmentation rules. Header Compression (SCHC) compression and fragmentation Rules.
This document formalizes the description of the rules for better This document formalizes the description of the Rules for better
interoperability between SCHC instances either to exchange a set of interoperability between SCHC instances either to exchange a set of
rules or to modify some rules parameters. Rules or to modify the parameters of some Rules.
Status of This Memo Status of This Memo
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction
2. Requirements Language . . . . . . . . . . . . . . . . . . . . 3 2. Requirements Language
3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. Terminology
4. SCHC rules . . . . . . . . . . . . . . . . . . . . . . . . . 5 4. SCHC Rules
4.1. Compression Rules . . . . . . . . . . . . . . . . . . . . 5 4.1. Compression Rules
4.2. Identifier generation . . . . . . . . . . . . . . . . . . 6 4.2. Identifier Generation
4.3. Convention for Field Identifier . . . . . . . . . . . . . 7 4.3. Convention for Field Identifier
4.4. Convention for Field length . . . . . . . . . . . . . . . 8 4.4. Convention for Field Length
4.5. Convention for Field position . . . . . . . . . . . . . . 8 4.5. Convention for Field Position
4.6. Convention for Direction Indicator . . . . . . . . . . . 8 4.6. Convention for Direction Indicator
4.7. Convention for Target Value . . . . . . . . . . . . . . . 9 4.7. Convention for Target Value
4.8. Convention for Matching Operator . . . . . . . . . . . . 9 4.8. Convention for Matching Operator
4.8.1. Matching Operator arguments . . . . . . . . . . . . . 9 4.8.1. Matching Operator Arguments
4.9. Convention for Compression Decompression Actions . . . . 9 4.9. Convention for Compression Decompression Actions
4.9.1. Compression Decompression Action arguments . . . . . 9 4.9.1. Compression Decompression Action Arguments
4.10. Fragmentation rule . . . . . . . . . . . . . . . . . . . 9 4.10. Fragmentation Rule
4.10.1. Fragmentation mode . . . . . . . . . . . . . . . . . 10 4.10.1. Fragmentation Mode
4.10.2. Fragmentation Header . . . . . . . . . . . . . . . . 10 4.10.2. Fragmentation Header
4.10.3. Last fragment format . . . . . . . . . . . . . . . . 11 4.10.3. Last Fragment Format
4.10.4. Acknowledgment behavior . . . . . . . . . . . . . . 11 4.10.4. Acknowledgment Behavior
4.10.5. Timer values . . . . . . . . . . . . . . . . . . . . 12 4.10.5. Timer Values
4.10.6. Fragmentation Parameter . . . . . . . . . . . . . . 12 4.10.6. Fragmentation Parameter
4.10.7. Layer 2 parameters . . . . . . . . . . . . . . . . . 12 4.10.7. Layer 2 Parameters
5. Rule definition . . . . . . . . . . . . . . . . . . . . . . . 13 5. Rule Definition
5.1. Compression rule . . . . . . . . . . . . . . . . . . . . 13 5.1. Compression Rule
5.2. Fragmentation rule . . . . . . . . . . . . . . . . . . . 14 5.2. Fragmentation Rule
5.3. YANG Tree . . . . . . . . . . . . . . . . . . . . . . . . 14 5.3. YANG Tree
6. YANG Module . . . . . . . . . . . . . . . . . . . . . . . . . 15 6. YANG Data Model
7. Implementation Status . . . . . . . . . . . . . . . . . . . . 45 7. IANA Considerations
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 46 7.1. URI Registration
8.1. URI Registration . . . . . . . . . . . . . . . . . . . 46 7.2. YANG Module Name Registration
8.2. YANG Module Name Registration . . . . . . . . . . . . . 46 8. Security Considerations
9. Security Considerations . . . . . . . . . . . . . . . . . . . 47 9. References
10. Annex A : Example . . . . . . . . . . . . . . . . . . . . . . 48 9.1. Normative References
11. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 51 9.2. Informative References
12. References . . . . . . . . . . . . . . . . . . . . . . . . . 51 Appendix A. Example
12.1. Normative References . . . . . . . . . . . . . . . . . . 51 Acknowledgments
12.2. Informative References . . . . . . . . . . . . . . . . . 53 Authors' Addresses
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 54
1. Introduction 1. Introduction
SCHC is a compression and fragmentation mechanism for constrained SCHC is a compression and fragmentation mechanism for constrained
networks defined in [RFC8724]. It is based on a static context networks defined in [RFC8724]. It is based on a static context
shared by two entities at the boundary of the constrained network. shared by two entities at the boundary of the constrained network.
[RFC8724] provides an informal representation of the rules used [RFC8724] provides an informal representation of the Rules used
either for compression/decompression (or C/D) or fragmentation/ either for compression/decompression (C/D) or fragmentation/
reassembly (or F/R). The goal of this document is to formalize the reassembly (F/R). The goal of this document is to formalize the
description of the rules to offer: description of the Rules to offer:
* the same definition on both ends, even if the internal * the same definition on both ends, even if the internal
representation is different; representation is different, and
* an update of the other end to set up some specific values (e.g. * an update of the other end to set up some specific values (e.g.,
IPv6 prefix, destination address,...). IPv6 prefix, destination address, etc.).
[I-D.ietf-lpwan-architecture] illustrates the exchange of rules using [LPWAN-ARCH] illustrates the exchange of Rules using the YANG data
the YANG data model. model.
This document defines a YANG module [RFC7950] to represent both This document defines a YANG data model [RFC7950] to represent both
compression and fragmentation rules, which leads to common compression and fragmentation Rules, which leads to common
representation for values for all the rules elements. representation for values for all the Rules' elements.
2. Requirements Language 2. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP "OPTIONAL" in this document are to be interpreted as described in
14 [RFC2119] [RFC8174] when, and only when, they appear in all BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here. capitals, as shown here.
3. Terminology 3. Terminology
This section defines the terminology and acronyms used in this This section defines the terminology and acronyms used in this
document. It extends the terminology of [RFC8376]. document. It extends the terminology of [RFC8376].
* App: LPWAN Application, as defined by [RFC8376]. An application App: Low-Power WAN (LPWAN) Application, as defined by [RFC8376]. An
sending/receiving packets to/from the Dev. application sending/receiving packets to/from the Dev.
* Bi: Bidirectional. Characterizes a Field Descriptor that applies Bi: Bidirectional. Characterizes a Field Descriptor that applies to
to headers of packets traveling in either direction (Up and Dw, headers of packets traveling in either direction (Up and Dw; see
see this glossary). this glossary).
* CDA: Compression/Decompression Action. Describes the pair of CDA: Compression/Decompression Action. Describes the pair of
actions that are performed at the compressor to compress a header actions that are performed at the compressor to compress a header
field and at the decompressor to recover the original value of the field and at the decompressor to recover the original value of the
header field. header field.
* Context: A set of Rules used to compress/decompress headers. Context: A set of Rules used to compress/decompress headers.
* Dev: Device, as defined by [RFC8376]. Dev: Device, as defined by [RFC8376].
* DevIID: Device Interface Identifier. The IID that identifies the DevIID: Device Interface Identifier. The IID that identifies the
Dev interface. Dev interface.
* DI: Direction Indicator. This field tells which direction of DI: Direction Indicator. This field tells which direction of packet
packet travel (Up, Dw or Bi) a Field Description applies to. This travel (Up, Dw, or Bi) a Field Descriptor applies to. This allows
allows for asymmetric processing, using the same Rule. for asymmetric processing, using the same Rule.
* Dw: Downlink direction for compression/decompression, from SCHC C/ Dw: Downlink direction for compression/decompression, from SCHC C/D
D in the network to SCHC C/D in the Dev. in the network to SCHC C/D in the Dev.
* FID: Field Identifier. This identifies the protocol and field a FID: Field Identifier or Field ID. This identifies the protocol and
Field Description applies to. field a Field Descriptor applies to.
* FL: Field Length is the length of the original packet header FL: Field Length. This is the length of the original packet header
field. It is expressed as a number of bits for header fields of field. It is expressed as a number of bits for header fields of
fixed lengths or as a type (e.g., variable, token length, ...) for fixed lengths or as a type (e.g., variable, token length, ...) for
field lengths that are unknown at the time of Rule creation. The Field Lengths that are unknown at the time of Rule creation. The
length of a header field is defined in the corresponding protocol length of a header field is defined in the corresponding protocol
specification (such as IPv6 or UDP). specification (such as IPv6 or UDP).
* FP: when a Field is expected to appear multiple times in a header, FP: Field Position. When a field is expected to appear multiple
Field Position specifies the occurrence this Field Description times in a header, the Field Position specifies the occurrence
applies to (for example, first uri-path option, second uri-path, this Field Descriptor applies to (for example, first Uri-Path
etc. in a CoAP header), counting from 1. The value 0 is special option, second Uri-Path, etc. in a Constrained Application
and means "don't care", see [RFC8724] Section 7.2. Protocol (CoAP) header), counting from 1. The value 0 is special
and means "don't care" (see Section 7.2 of [RFC8724]).
* IID: Interface Identifier. See the IPv6 addressing architecture IID: Interface Identifier. See the IPv6 addressing architecture
[RFC7136]. [RFC7136].
* L2 Word: this is the minimum subdivision of payload data that the L2 Word: This is the minimum subdivision of payload data that the
L2 will carry. In most L2 technologies, the L2 Word is an octet. Layer 2 (L2) will carry. In most L2 technologies, the L2 Word is
In bit-oriented radio technologies, the L2 Word might be a single an octet. In bit-oriented radio technologies, the L2 Word might
bit. The L2 Word size is assumed to be constant over time for be a single bit. The L2 Word size is assumed to be constant over
each device. time for each device.
* MO: Matching Operator. An operator used to match a value MO: Matching Operator. An operator used to match a value contained
contained in a header field with a value contained in a Rule. in a header field with a value contained in a Rule.
* Rule ID (Rule Identifier): An identifier for a Rule. SCHC C/D on RuleID: Rule Identifier. An identifier for a Rule. SCHC C/D on
both sides share the same Rule ID for a given packet. A set of both sides share the same RuleID for a given packet. A set of
Rule IDs are used to support SCHC F/R functionality. RuleIDs are used to support SCHC F/R functionality.
* TV: Target value. A value contained in a Rule that will be TV: Target Value. A value contained in a Rule that will be matched
matched with the value of a header field. with the value of a header field.
* Up: Uplink direction for compression/decompression, from the Dev Up: Uplink direction for compression/decompression, from the Dev
SCHC C/D to the network SCHC C/D. SCHC C/D to the network SCHC C/D.
4. SCHC rules 4. SCHC Rules
SCHC compression is generic, the main mechanism does not refer to a SCHC compression is generic; the main mechanism does not refer to a
specific protocol. Any header field is abstracted through an Field specific protocol. Any header field is abstracted through a Field
Identifier (FID), a position (FP), a direction (DI), and a value that Identifier (FID), a position (FP), a direction (DI), and a value that
can be a numerical value or a string. [RFC8724] and [RFC8824] can be a numerical value or a string. [RFC8724] and [RFC8824]
specify fields for IPv6 [RFC8200], UDP[RFC0768], CoAP [RFC7252] specify fields for IPv6 [RFC8200], UDP [RFC0768], and CoAP [RFC7252],
including options defined for no server response [RFC7967] and OSCORE including options defined for no server response [RFC7967] and Object
[RFC8613]. For the latter [RFC8824] splits this field into sub- Security for Constrained RESTful Environments (OSCORE) [RFC8613].
fields. For the latter, [RFC8824] splits this field into subfields.
SCHC fragmentation requires a set of common parameters that are SCHC fragmentation requires a set of common parameters that are
included in a rule. These parameters are defined in [RFC8724]. included in a Rule. These parameters are defined in [RFC8724].
The YANG data model enables the compression and the fragmentation The YANG data model enables the compression and the fragmentation
selection using the feature statement. selection using the feature statement.
4.1. Compression Rules 4.1. Compression Rules
[RFC8724] proposes an informal representation of the compression [RFC8724] proposes an informal representation of the compression
rule. A compression context for a device is composed of a set of Rule. A compression context for a device is composed of a set of
rules. Each rule contains information to describe a specific field Rules. Each Rule contains information to describe a specific field
in the header to be compressed. in the header to be compressed.
+-----------------------------------------------------------------+ +-----------------------------------------------------------------+
| Rule N | | Rule N |
+-----------------------------------------------------------------+| +-----------------------------------------------------------------+|
| Rule i || | Rule i ||
+-----------------------------------------------------------------+|| +-----------------------------------------------------------------+||
| (FID) Rule 1 ||| | (FID) Rule 1 |||
|+-------+--+--+--+------------+-----------------+---------------+||| |+-------+--+--+--+------------+-----------------+---------------+|||
||Field 1|FL|FP|DI|Target Value|Matching Operator|Comp/Decomp Act|||| ||Field 1|FL|FP|DI|Target Value|Matching Operator|Comp/Decomp Act||||
skipping to change at page 6, line 25 skipping to change at line 234
|+-------+--+--+--+------------+-----------------+---------------+||| |+-------+--+--+--+------------+-----------------+---------------+|||
||... |..|..|..| ... | ... | ... |||| ||... |..|..|..| ... | ... | ... ||||
|+-------+--+--+--+------------+-----------------+---------------+||/ |+-------+--+--+--+------------+-----------------+---------------+||/
||Field N|FL|FP|DI|Target Value|Matching Operator|Comp/Decomp Act||| ||Field N|FL|FP|DI|Target Value|Matching Operator|Comp/Decomp Act|||
|+-------+--+--+--+------------+-----------------+---------------+|/ |+-------+--+--+--+------------+-----------------+---------------+|/
| | | |
\-----------------------------------------------------------------/ \-----------------------------------------------------------------/
Figure 1: Compression Decompression Context Figure 1: Compression Decompression Context
4.2. Identifier generation 4.2. Identifier Generation
Identifiers used in the SCHC YANG data model are from the identityref Identifiers used in the SCHC YANG data model are from the identityref
statement to ensure global uniqueness and easy augmentation if statement to ensure global uniqueness and easy augmentation if
needed. The principle to define a new type based on a group of needed. The principle to define a new type based on a group of
identityref is the following: identityref is the following:
* define a main identity ending with the keyword base-type. * Define a main identity ending with the keyword base-type.
* derive all the identities used in the Data Model from this base * Derive all the identities used in the data model from this base
type. type.
* create a typedef from this base type. * Create a typedef from this base type.
The example (Figure 2) shows how an identityref is created for RCS The example below (Figure 2) shows how an identityref is created for
(Reassembly Check Sequence) algorithms used during SCHC Reassembly Check Sequence (RCS) algorithms used during SCHC
fragmentation. fragmentation.
identity rcs-algorithm-base-type { identity rcs-algorithm-base-type {
description description
"Identify which algorithm is used to compute RCS. "Identify which algorithm is used to compute RCS.
The algorithm also defines the size of the RCS field."; The algorithm also defines the size of the RCS field.";
reference reference
"RFC 8724 SCHC: Generic Framework for Static Context Header "RFC 8724 SCHC: Generic Framework for Static Context Header
Compression and Fragmentation"; Compression and Fragmentation";
} }
identity rcs-crc32 { identity rcs-crc32 {
base rcs-algorithm-base-type; base rcs-algorithm-base-type;
description description
"CRC 32 defined as default RCS in RFC8724. This RCS is "CRC32 defined as default RCS in RFC 8724. This RCS is
4 bytes long."; 4 bytes long.";
reference reference
"RFC 8724 SCHC: Generic Framework for Static Context Header "RFC 8724 SCHC: Generic Framework for Static Context Header
Compression and Fragmentation"; Compression and Fragmentation";
} }
typedef rcs-algorithm-type { typedef rcs-algorithm-type {
type identityref { type identityref {
base rcs-algorithm-base-type; base rcs-algorithm-base-type;
} }
description description
"Define the type for RCS algorithm in rules."; "Define the type for RCS algorithm in Rules.";
} }
Figure 2: Principle to define a type based on identityref. Figure 2: Principle to Define a Type Based on identityref
4.3. Convention for Field Identifier 4.3. Convention for Field Identifier
In the process of compression, the headers of the original packet are In the process of compression, the headers of the original packet are
first parsed to create a list of fields. This list of fields is first parsed to create a list of fields. This list of fields is
matched against the rules to find the appropriate rule and apply matched against the Rules to find the appropriate Rule and apply
compression. [RFC8724] does not state how the field ID value is compression. [RFC8724] does not state how the Field ID value is
constructed. In examples, identification is done through a string constructed. In examples, identification is done through a string
indexed by the protocol name (e.g. IPv6.version, CoAP.version,...). indexed by the protocol name (e.g., IPv6.version, CoAP.version,
etc.).
The current YANG data model includes fields definitions found in The current YANG data model includes field definitions found in
[RFC8724], [RFC8824]. [RFC8724] and [RFC8824].
Using the YANG data model, each field MUST be identified through a Using the YANG data model, each field MUST be identified through a
global YANG identityref. global YANG identityref.
A YANG field ID for the protocol is always derived from the fid-base-
type. Then an identity for each protocol is specified using the A YANG Field ID for the protocol is always derived from the fid-base-
type. Then, an identity for each protocol is specified using the
naming convention fid-<<protocol name>>-base-type. All possible naming convention fid-<<protocol name>>-base-type. All possible
fields for this protocol MUST derive from the protocol identity. The fields for this protocol MUST derive from the protocol identity. The
naming convention is "fid-" followed by the protocol name and the naming convention is "fid-" followed by the protocol name and the
field name. If a field has to be divided into sub-fields, the field field name. If a field has to be divided into subfields, the field
identity serves as a base. identity serves as a base.
The full field-id definition is found in Section 6. A type is The full field-id definition is found in Section 6. A type is
defined for IPv6 protocol, and each field is based on it. Note that defined for the IPv6 protocol, and each field is based on it. Note
the DiffServ bits derive from the Traffic Class identity. that the Diffserv bits derive from the Traffic Class identity.
4.4. Convention for Field length 4.4. Convention for Field Length
Field length is either an integer giving the size of a field in bits The Field Length is either an integer giving the size of a field in
or a specific function. [RFC8724] defines the "var" function which bits or a specific function. [RFC8724] defines the "var" function,
allows variable length fields (whose length is expressed in bytes) which allows variable-length fields (whose length is expressed in
and [RFC8824] defines the "tkl" function for managing the CoAP Token bytes), and [RFC8824] defines the "tkl" function for managing the
length field. CoAP Token Length field.
The naming convention is "fl-" followed by the function name. The naming convention is "fl-" followed by the function name.
The field length function can be defined as an identityref as The Field Length function can be defined as an identityref, as
described in Section 6. Therefore, the type for field length is a described in Section 6. Therefore, the type for the Field Length is
union between an integer giving the size of the length in bits and a union between an integer giving the size of the length in bits and
the identityref. the identityref.
4.5. Convention for Field position 4.5. Convention for Field Position
Field position is a positive integer which gives the occurrence times The Field Position is a positive integer that gives the occurrence
of a specific field from the header start. The default value is 1, times of a specific field from the header start. The default value
and incremented at each repetition. Value 0 indicates that the is 1 and is incremented at each repetition. Value 0 indicates that
position is not important and is not considered during the rule the position is not important and is not considered during the Rule
selection process. selection process.
Field position is a positive integer. The type is uint8. The Field Position is a positive integer. The type is uint8.
4.6. Convention for Direction Indicator 4.6. Convention for Direction Indicator
The Direction Indicator (di) is used to tell if a field appears in The Direction Indicator is used to tell if a field appears in both
both directions (Bi) or only uplink (Up) or Downlink (Dw). The directions (Bi) or only uplink (Up) or Downlink (Dw). The naming
naming convention is "di" followed by the Direction Indicator name. convention is "di" followed by the Direction Indicator name.
The type is "di-type". The type is "di-type".
4.7. Convention for Target Value 4.7. Convention for Target Value
The Target Value is a list of binary sequences of any length, aligned The Target Value is a list of binary sequences of any length, aligned
to the left. In the rule, the structure will be used as a list, with to the left. In the Rule, the structure will be used as a list, with
index as a key. The highest index value is used to compute the size the index as a key. The highest index value is used to compute the
of the index sent in residue for the match-mapping CDA (Compression size of the index sent in residue for the match-mapping Compression
Decompression Action). The index can specify several values: Decompression Action (CDA). The index can specify several values:
* For Equal and MSB, Target Value contains a single element. * For equal and most significant bits (MSBs), the Target Value
Therefore, the index is set to 0. contains a single element. Therefore, the index is set to 0.
* For match-mapping, Target Value can contain several elements. * For match-mapping, the Target Value can contain several elements.
Index values MUST start from 0 and MUST be contiguous. Index values MUST start from 0 and MUST be contiguous.
If the header field contains text, the binary sequence uses the same If the header field contains text, the binary sequence uses the same
encoding. encoding.
4.8. Convention for Matching Operator 4.8. Convention for Matching Operator
Matching Operator (MO) is a function applied between a field value The Matching Operator (MO) is a function applied between a field
provided by the parsed header and the target value. [RFC8724] value provided by the parsed header and the Target Value. [RFC8724]
defines 4 MO. defines 4 MOs.
The naming convention is "mo-" followed by the MO name. The naming convention is "mo-" followed by the MO name.
The type is "mo-type" The type is "mo-type".
4.8.1. Matching Operator arguments 4.8.1. Matching Operator Arguments
They are viewed as a list, built with a tv-struct (see Section 4.7). They are viewed as a list, built with a tv-struct (see Section 4.7).
4.9. Convention for Compression Decompression Actions 4.9. Convention for Compression Decompression Actions
Compression Decompression Action (CDA) identifies the function to use The Compression Decompression Action (CDA) identifies the function to
for compression or decompression. [RFC8724] defines 6 CDA. use for compression or decompression. [RFC8724] defines 7 CDAs.
The naming convention is "cda-" followed by the CDA name. The naming convention is "cda-" followed by the CDA name.
4.9.1. Compression Decompression Action arguments 4.9.1. Compression Decompression Action Arguments
Currently no CDA requires arguments, but in the future some CDA may Currently no CDA requires arguments, but some CDAs may require one or
require one or several arguments. They are viewed as a list, of several arguments in the future. They are viewed as a list of
target-value type. target-value type.
4.10. Fragmentation rule 4.10. Fragmentation Rule
Fragmentation is optional in the data model and depends on the Fragmentation is optional in the data model and depends on the
presence of the "fragmentation" feature. presence of the "fragmentation" feature.
Most of the fragmentation parameters are listed in Annex D of Most of the fragmentation parameters are listed in Appendix D of
[RFC8724]. [RFC8724].
Since fragmentation rules work for a specific direction, they MUST Since fragmentation Rules work for a specific direction, they MUST
contain a mandatory direction indicator. The type is the same as the contain a mandatory Direction Indicator. The type is the same as the
one used in compression entries, but bidirectional MUST NOT be used. one used in compression entries, but bidirectional MUST NOT be used.
4.10.1. Fragmentation mode 4.10.1. Fragmentation Mode
[RFC8724] defines 3 fragmentation modes: [RFC8724] defines 3 fragmentation modes:
* No Ack: this mode is unidirectional, no acknowledgment is sent * No ACK: This mode is unidirectional; no acknowledgment is sent
back. back.
* Ack Always: each fragmentation window must be explicitly * ACK Always: Each fragmentation window must be explicitly
acknowledged before going to the next. acknowledged before going to the next.
* Ack on Error: A window is acknowledged only when the receiver * ACK on Error: A window is acknowledged only when the receiver
detects some missing fragments. detects some missing fragments.
The type is "fragmentation-mode-type". The naming convention is The type is "fragmentation-mode-type". The naming convention is
"fragmentation-mode-" followed by the fragmentation mode name. "fragmentation-mode-" followed by the fragmentation mode name.
4.10.2. Fragmentation Header 4.10.2. Fragmentation Header
A data fragment header, starting with the rule ID, can be sent in the A data fragment header, starting with the RuleID, can be sent in the
fragmentation direction. [RFC8724] indicates that the SCHC header fragmentation direction. [RFC8724] indicates that the SCHC header
may be composed of (cf. Figure 3): may be composed of the following (cf. Figure 3):
* a Datagram Tag (Dtag) identifying the datagram being fragmented if * a Datagram Tag (DTag) identifying the datagram being fragmented if
the fragmentation applies concurrently on several datagrams. This the fragmentation applies concurrently on several datagrams. This
field is optional and its length is defined by the rule. field is optional, and its length is defined by the Rule.
* a Window (W) used in Ack-Always and Ack-on-Error modes. In Ack- * a Window (W) used in ACK-Always and ACK-on-Error modes. In ACK-
Always, its size is 1. In Ack-on-Error, it depends on the rule. Always, its size is 1. In ACK-on-Error, it depends on the Rule.
This field is not needed in No-Ack mode. This field is not needed in No-ACK mode.
* a Fragment Compressed Number (FCN) indicating the fragment/tile * a Fragment Compressed Number (FCN) indicating the fragment/tile
position within the window. This field is mandatory on all modes position within the window. This field is mandatory on all modes
defined in [RFC8724], its size is defined by the rule. defined in [RFC8724], and its size is defined by the Rule.
|-- SCHC Fragment Header ----| |-- SCHC Fragment Header ----|
|-- T --|-M-|-- N --| |-- T --|-M-|-- N --|
+-- ... -+- ... -+---+- ... -+--------...-------+~~~~~~~~~~~~~~~~~~~~ +-- ... -+- ... -+---+- ... -+--------...-------+~~~~~~~~~~~~~~~~~~~~
| RuleID | DTag | W | FCN | Fragment Payload | padding (as needed) | RuleID | DTag | W | FCN | Fragment Payload | padding (as needed)
+-- ... -+- ... -+---+- ... -+--------...-------+~~~~~~~~~~~~~~~~~~~~ +-- ... -+- ... -+---+- ... -+--------...-------+~~~~~~~~~~~~~~~~~~~~
Figure 3: Data fragment header from RFC8724 Figure 3: Data Fragment Header from RFC 8724
4.10.3. Last fragment format 4.10.3. Last Fragment Format
The last fragment of a datagram is sent with an RCS (Reassembly Check The last fragment of a datagram is sent with a Reassembly Check
Sequence) field to detect residual transmission error and possible Sequence (RCS) field to detect residual transmission errors and
losses in the last window. [RFC8724] defines a single algorithm possible losses in the last window. [RFC8724] defines a single
based on Ethernet CRC computation. algorithm based on Ethernet CRC computation.
The naming convention is "rcs-" followed by the algorithm name. The naming convention is "rcs-" followed by the algorithm name.
For Ack-on-Error mode, the All-1 fragment may just contain the RCS or For ACK-on-Error mode, the All-1 fragment may just contain the RCS or
can include a tile. The parameters define the behavior: can include a tile. The following parameters define the behavior:
* all-1-data-no: the last fragment contains no data, just the RCS * all-1-data-no: The last fragment contains no data, just the RCS.
* all-1-data-yes: the last fragment includes a single tile and the * all-1-data-yes: The last fragment includes a single tile and the
RCS RCS.
* all-1-data-sender-choice: the last fragment may or may not contain * all-1-data-sender-choice: The last fragment may or may not contain
a single tile. The receiver can detect if a tile is present. a single tile. The receiver can detect if a tile is present.
The naming convention is "all-1-data-" followed by the behavior The naming convention is "all-1-data-" followed by the behavior
identifier. identifier.
4.10.4. Acknowledgment behavior 4.10.4. Acknowledgment Behavior
The acknowledgment fragment header goes in the opposite direction of The acknowledgment fragment header goes in the opposite direction of
data. [RFC8724] defines the header, composed of (see Figure 4): data. [RFC8724] defines the header, which is composed of the
following (see Figure 4):
* a Dtag (if present). * a DTag (if present).
* a mandatory window as in the data fragment. * a mandatory window, as in the data fragment.
* a C bit giving the status of RCS validation. In case of failure, * a C bit giving the status of RCS validation. In case of failure,
a bitmap follows, indicating the received tile. a bitmap follows, indicating the received tile.
|--- SCHC ACK Header ----| |--- SCHC ACK Header ----|
|-- T --|-M-| 1 | |-- T --|-M-| 1 |
+-- ... -+- ... -+---+---+~~~~~~~~~~~~~~~~~~ +-- ... -+- ... -+---+---+~~~~~~~~~~~~~~~~~~
| RuleID | DTag | W |C=1| padding as needed (success) | RuleID | DTag | W |C=1| padding as needed (success)
+-- ... -+- ... -+---+---+~~~~~~~~~~~~~~~~~~ +-- ... -+- ... -+---+---+~~~~~~~~~~~~~~~~~~
+-- ... -+- ... -+---+---+------ ... ------+~~~~~~~~~~~~~~~ +-- ... -+- ... -+---+---+------ ... ------+~~~~~~~~~~~~~~~
| RuleID | DTag | W |C=0|Compressed Bitmap| pad. as needed (failure) | RuleID | DTag | W |C=0|Compressed Bitmap| pad. as needed (failure)
+-- ... -+- ... -+---+---+------ ... ------+~~~~~~~~~~~~~~~ +-- ... -+- ... -+---+---+------ ... ------+~~~~~~~~~~~~~~~
Figure 4: Acknowledgment fragment header for RFC8724 Figure 4: Acknowledgment Fragment Header for RFC 8724
For Ack-on-Error, SCHC defines when an acknowledgment can be sent. For ACK-on-Error, SCHC defines when an acknowledgment can be sent.
This can be at any time defined by the layer 2, at the end of a This can be at any time defined by the Layer 2, at the end of a
window (FCN all-0) or as a response to receiving the last fragment window (FCN all-0), or as a response to receiving the last fragment
(FCN all-1). The naming convention is "ack-behavior" followed by the (FCN all-1). The naming convention is "ack-behavior" followed by the
algorithm name. algorithm name.
4.10.5. Timer values 4.10.5. Timer Values
The state machine requires some common values to handle fragmentation The state machine requires some common values to handle fragmentation
correctly. correctly.
* retransmission-timer gives the duration before sending an ack * The Retransmission Timer gives the duration before sending an ACK
request (cf. section 8.2.2.4. of [RFC8724]). If specified, value request (cf. Section 8.2.2.4 of [RFC8724]). If specified, the
MUST be strictly positive. value MUST be strictly positive.
* inactivity-timer gives the duration before aborting a * The Inactivity Timer gives the duration before aborting a
fragmentation session (cf. section 8.2.2.4. of [RFC8724]). The fragmentation session (cf. Section 8.2.2.4 of [RFC8724]). The
value 0 explicitly indicates that this timer is disabled. value 0 explicitly indicates that this timer is disabled.
[RFC8724] do not specify any range for these timers. [RFC9011] [RFC8724] does not specify any range for these timers. [RFC9011]
recommends a duration of 12 hours. In fact, the value range should recommends a duration of 12 hours. In fact, the value range should
be between milliseconds for real time systems to several days. To be between milliseconds for real-time systems to several days for
allow a large range of applications, two parameters must be worse-than-best-effort systems. To allow a large range of
specified: applications, two parameters must be specified:
* the duration of a tick. It is computed by this formula 2^tick- * the duration of a tick. It is computed by this formula: 2^(tick-
duration/10^6. When tick-duration is set to 0, the unit is the duration)/10^6. When tick-duration is set to 0, the unit is the
microsecond. The default value of 20 leads to a unit of 1.048575 microsecond. The default value of 20 leads to a unit of 1.048575
second. A value of 32 leads to a tick duration of about 1 hour 11 seconds. A value of 32 leads to a tick-duration of about 1 hour
minutes. 11 minutes.
* the number of ticks in the predefined unit. With the default * the number of ticks in the predefined unit. With the default
tick-duration value of 20, the timers can cover a range between tick-duration value of 20, the timers can cover a range between
1.0 sec and 19 hours covering [RFC9011] recommendation. 1.0 second and 19 hours, as recommended in [RFC9011].
4.10.6. Fragmentation Parameter 4.10.6. Fragmentation Parameter
The SCHC fragmentation protocol specifies the number of attempts The SCHC fragmentation protocol specifies the number of attempts
before aborting through the parameter: before aborting through the parameter:
* max-ack-requests (cf. section 8.2.2.4. of [RFC8724]). * max-ack-requests (cf. Section 8.2.2.4 of [RFC8724])
4.10.7. Layer 2 parameters 4.10.7. Layer 2 Parameters
The data model includes two parameters needed for fragmentation: The data model includes two parameters needed for fragmentation:
* l2-word-size: [RFC8724] base fragmentation, in bits, on a layer 2 * l2-word-size: [RFC8724] base fragmentation, in bits, on a Layer 2
word which can be of any length. The default value is 8 and Word that can be of any length. The default value is 8 and
correspond to the default value for byte aligned layer 2. A value corresponds to the default value for the byte-aligned Layer 2. A
of 1 will indicate that there is no alignment and no need for value of 1 will indicate that there is no alignment and no need
padding. for padding.
* maximum-packet-size: defines the maximum size of an uncompressed * maximum-packet-size: defines the maximum size of an uncompressed
datagram. By default, the value is set to 1280 bytes. datagram. By default, the value is set to 1280 bytes.
They are defined as unsigned integers, see Section 6. They are defined as unsigned integers; see Section 6.
5. Rule definition 5. Rule Definition
A rule is identified by a unique rule identifier (rule ID) comprising A Rule is identified by a unique Rule Identifier (RuleID) comprising
both a Rule ID value and a Rule ID length. The YANG grouping rule- both a RuleID value and a RuleID length. The YANG grouping rule-id-
id-type defines the structure used to represent a rule ID. A length type defines the structure used to represent a RuleID. A length of 0
of 0 is allowed to represent an implicit rule. is allowed to represent an implicit Rule.
Three natures of rules are defined in [RFC8724]: Three natures of Rules are defined in [RFC8724]:
* Compression: a compression rule is associated with the rule ID. * Compression: A compression Rule is associated with the RuleID.
* No compression: this identifies the default rule used to send a * No-compression: This identifies the default Rule used to send a
packet integrally when no compression rule was found (see packet integrally when no-compression Rule was found (see
[RFC8724] section 6). Section 6 of [RFC8724]).
* Fragmentation: fragmentation parameters are associated with the * Fragmentation: Fragmentation parameters are associated with the
rule ID. Fragmentation is optional and feature "fragmentation" RuleID. Fragmentation is optional, and the feature
should be set. "fragmentation" should be set.
The YANG data model introduces respectively these three identities : The YANG data model respectively introduces these three identities :
* nature-compression * nature-compression
* nature-no-compression * nature-no-compression
* nature-fragmentation * nature-fragmentation
The naming convention is "nature-" followed by the nature identifier. The naming convention is "nature-" followed by the nature identifier.
To access a specific rule, the rule ID length and value are used as a To access a specific Rule, the RuleID length and value are used as a
key. The rule is either a compression or a fragmentation rule. key. The Rule is either a compression or a fragmentation Rule.
5.1. Compression rule 5.1. Compression Rule
A compression rule is composed of entries describing its processing. A compression Rule is composed of entries describing its processing.
An entry contains all the information defined in Figure 1 with the An entry contains all the information defined in Figure 1 with the
types defined above. types defined above.
The compression rule described Figure 1 is defined by compression- The compression Rule described Figure 1 is defined by compression-
content. It defines a list of compression-rule-entry, indexed by content. It defines a list of compression-rule-entry, indexed by
their field id, position and direction. The compression-rule-entry their Field ID, position, and direction. The compression-rule-entry
element represent a line of the table Figure 1. Their type reflects element represents a line in Figure 1. Their type reflects the
the identifier types defined in Section 4.1 identifier types defined in Section 4.1.
Some checks are performed on the values: Some checks are performed on the values:
* target value MUST be present for MO different from ignore. * When MO is ignore, no Target Value is needed; for other MOs, there
MUST be a Target Value present.
* when MSB MO is specified, the matching-operator-value must be * When MSB MO is specified, the matching-operator-value must be
present present.
5.2. Fragmentation rule 5.2. Fragmentation Rule
A Fragmentation rule is composed of entries describing the protocol A fragmentation Rule is composed of entries describing the protocol
behavior. Some on them are numerical entries, others are identifiers behavior. Some on them are numerical entries, others are identifiers
defined in Section 4.10. defined in Section 4.10.
5.3. YANG Tree 5.3. YANG Tree
The YANG data model described in this document conforms to the The YANG data model described in this document conforms to the
Network Management Datastore Architecture defined in [RFC8342]. Network Management Datastore Architecture defined in [RFC8342].
module: ietf-schc module: ietf-schc
+--rw schc +--rw schc
skipping to change at page 15, line 32 skipping to change at line 660
| +--rw value? binary | +--rw value? binary
+--rw matching-operator schc:mo-type +--rw matching-operator schc:mo-type
+--rw matching-operator-value* [index] +--rw matching-operator-value* [index]
| +--rw index uint16 | +--rw index uint16
| +--rw value? binary | +--rw value? binary
+--rw comp-decomp-action schc:cda-type +--rw comp-decomp-action schc:cda-type
+--rw comp-decomp-action-value* [index] +--rw comp-decomp-action-value* [index]
+--rw index uint16 +--rw index uint16
+--rw value? binary +--rw value? binary
Figure 5: Overview of SCHC data model Figure 5: Overview of the SCHC Data Model
6. YANG Module 6. YANG Data Model
<CODE BEGINS> file "ietf-schc@2022-10-09.yang" <CODE BEGINS> file "ietf-schc@2023-01-28.yang"
module ietf-schc { module ietf-schc {
yang-version 1.1; yang-version 1.1;
namespace "urn:ietf:params:xml:ns:yang:ietf-schc"; namespace "urn:ietf:params:xml:ns:yang:ietf-schc";
prefix schc; prefix schc;
organization organization
"IETF IPv6 over Low Power Wide-Area Networks (lpwan) working "IETF IPv6 over Low Power Wide-Area Networks (lpwan) Working
group"; Group";
contact contact
"WG Web: <https://datatracker.ietf.org/wg/lpwan/about/> "WG Web: <https://datatracker.ietf.org/wg/lpwan/about/>
WG List: <mailto:lp-wan@ietf.org> WG List: <mailto:lp-wan@ietf.org>
Editor: Laurent Toutain Editor: Laurent Toutain
<mailto:laurent.toutain@imt-atlantique.fr> <mailto:laurent.toutain@imt-atlantique.fr>
Editor: Ana Minaburo Editor: Ana Minaburo
<mailto:ana@ackl.io>"; <mailto:ana@ackl.io>";
description description
" "Copyright (c) 2023 IETF Trust and the persons identified as
Copyright (c) 2022 IETF Trust and the persons identified as
authors of the code. All rights reserved. authors of the code. All rights reserved.
Redistribution and use in source and binary forms, with or Redistribution and use in source and binary forms, with or
without modification, is permitted pursuant to, and subject to without modification, is permitted pursuant to, and subject to
the license terms contained in, the Revised BSD License set the license terms contained in, the Revised BSD License set
forth in Section 4.c of the IETF Trust's Legal Provisions forth in Section 4.c of the IETF Trust's Legal Provisions
Relating to IETF Documents Relating to IETF Documents
(https://trustee.ietf.org/license-info). (https://trustee.ietf.org/license-info).
This version of this YANG module is part of RFC 9363
This version of this YANG module is part of RFC XXXX (https://www.rfc-editor.org/info/rfc9363); see the RFC itself
(https://www.rfc-editor.org/info/rfcXXXX); see the RFC itself
for full legal notices. for full legal notices.
The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL', 'SHALL The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL', 'SHALL
NOT', 'SHOULD', 'SHOULD NOT', 'RECOMMENDED', 'NOT RECOMMENDED', NOT', 'SHOULD', 'SHOULD NOT', 'RECOMMENDED', 'NOT RECOMMENDED',
'MAY', and 'OPTIONAL' in this document are to be interpreted as 'MAY', and 'OPTIONAL' in this document are to be interpreted as
described in BCP 14 (RFC 2119) (RFC 8174) when, and only when, described in BCP 14 (RFC 2119) (RFC 8174) when, and only when,
they appear in all capitals, as shown here. they appear in all capitals, as shown here.
*************************************************************** ***************************************************************
Generic data model for the Static Context Header Compression
Rule for SCHC, based on RFCs 8724 and 8824. Including
compression, no-compression, and fragmentation Rules.
Generic Data model for Static Context Header Compression Rule This module is a YANG data model for SCHC Rules (RFCs 8724 and
for SCHC, based on RFC 8724 and RFC8824. Include compression, 8824). RFC 8724 describes compression Rules in an abstract
no compression and fragmentation rules.
This module is a YANG model for SCHC rules (RFC 8724 and
RFC8824). RFC 8724 describes compression rules in a abstract
way through a table. way through a table.
|-----------------------------------------------------------------| |-----------------------------------------------------------------|
| (FID) Rule 1 | | (FID) Rule 1 |
|+-------+--+--+--+------------+-----------------+---------------+| |+-------+--+--+--+------------+-----------------+---------------+|
||Field 1|FL|FP|DI|Target Value|Matching Operator|Comp/Decomp Act|| ||Field 1|FL|FP|DI|Target Value|Matching Operator|Comp/Decomp Act||
|+-------+--+--+--+------------+-----------------+---------------+| |+-------+--+--+--+------------+-----------------+---------------+|
||Field 2|FL|FP|DI|Target Value|Matching Operator|Comp/Decomp Act|| ||Field 2|FL|FP|DI|Target Value|Matching Operator|Comp/Decomp Act||
|+-------+--+--+--+------------+-----------------+---------------+| |+-------+--+--+--+------------+-----------------+---------------+|
||... |..|..|..| ... | ... | ... || ||... |..|..|..| ... | ... | ... ||
|+-------+--+--+--+------------+-----------------+---------------+| |+-------+--+--+--+------------+-----------------+---------------+|
||Field N|FL|FP|DI|Target Value|Matching Operator|Comp/Decomp Act|| ||Field N|FL|FP|DI|Target Value|Matching Operator|Comp/Decomp Act||
skipping to change at page 16, line 49 skipping to change at line 717
|+-------+--+--+--+------------+-----------------+---------------+| |+-------+--+--+--+------------+-----------------+---------------+|
||Field 1|FL|FP|DI|Target Value|Matching Operator|Comp/Decomp Act|| ||Field 1|FL|FP|DI|Target Value|Matching Operator|Comp/Decomp Act||
|+-------+--+--+--+------------+-----------------+---------------+| |+-------+--+--+--+------------+-----------------+---------------+|
||Field 2|FL|FP|DI|Target Value|Matching Operator|Comp/Decomp Act|| ||Field 2|FL|FP|DI|Target Value|Matching Operator|Comp/Decomp Act||
|+-------+--+--+--+------------+-----------------+---------------+| |+-------+--+--+--+------------+-----------------+---------------+|
||... |..|..|..| ... | ... | ... || ||... |..|..|..| ... | ... | ... ||
|+-------+--+--+--+------------+-----------------+---------------+| |+-------+--+--+--+------------+-----------------+---------------+|
||Field N|FL|FP|DI|Target Value|Matching Operator|Comp/Decomp Act|| ||Field N|FL|FP|DI|Target Value|Matching Operator|Comp/Decomp Act||
|+-------+--+--+--+------------+-----------------+---------------+| |+-------+--+--+--+------------+-----------------+---------------+|
|-----------------------------------------------------------------| |-----------------------------------------------------------------|
This module specifies a global data model that can be used for This module specifies a global data model that can be used for
rule exchanges or modification. It specifies both the data model Rule exchanges or modification. It specifies both the data
format and the global identifiers used to describe some model format and the global identifiers used to describe some
operations in fields. operations in fields.
This data model applies to both compression and fragmentation."; This data model applies to both compression and fragmentation.";
revision 2022-10-09 { revision 2023-01-28 {
description description
"Initial version from RFC XXXX."; "Initial version from RFC 9363.";
reference reference
"RFC XXX: Data Model for Static Context Header Compression "RFC 9363 A YANG Data Model for Static Context Header
(SCHC)"; Compression (SCHC)";
} }
feature compression { feature compression {
description description
"SCHC compression capabilities are taken into account."; "SCHC compression capabilities are taken into account.";
} }
feature fragmentation { feature fragmentation {
description description
"SCHC fragmentation capabilities are taken into account."; "SCHC fragmentation capabilities are taken into account.";
skipping to change at page 18, line 14 skipping to change at line 778
base fid-ipv6-base-type; base fid-ipv6-base-type;
description description
"IPv6 Traffic Class field."; "IPv6 Traffic Class field.";
reference reference
"RFC 8200 Internet Protocol, Version 6 (IPv6) Specification"; "RFC 8200 Internet Protocol, Version 6 (IPv6) Specification";
} }
identity fid-ipv6-trafficclass-ds { identity fid-ipv6-trafficclass-ds {
base fid-ipv6-trafficclass; base fid-ipv6-trafficclass;
description description
"IPv6 Traffic Class field: DiffServ field."; "IPv6 Traffic Class field: Diffserv field.";
reference reference
"RFC 8200 Internet Protocol, Version 6 (IPv6) Specification, "RFC 8200 Internet Protocol, Version 6 (IPv6) Specification,
RFC 3168 The Addition of Explicit Congestion Notification RFC 3168 The Addition of Explicit Congestion Notification
(ECN) to IP"; (ECN) to IP";
} }
identity fid-ipv6-trafficclass-ecn { identity fid-ipv6-trafficclass-ecn {
base fid-ipv6-trafficclass; base fid-ipv6-trafficclass;
description description
"IPv6 Traffic Class field: ECN field."; "IPv6 Traffic Class field: ECN field.";
skipping to change at page 22, line 25 skipping to change at line 981
} }
identity fid-coap-token { identity fid-coap-token {
base fid-coap-base-type; base fid-coap-base-type;
description description
"CoAP token."; "CoAP token.";
reference reference
"RFC 7252 The Constrained Application Protocol (CoAP)"; "RFC 7252 The Constrained Application Protocol (CoAP)";
} }
identity fid-coap-option-if-match { identity fid-coap-option {
base fid-coap-base-type; base fid-coap-base-type;
description description
"Generic CoAP option.";
reference
"RFC 7252 The Constrained Application Protocol (CoAP)";
}
identity fid-coap-option-if-match {
base fid-coap-option;
description
"CoAP option If-Match."; "CoAP option If-Match.";
reference reference
"RFC 7252 The Constrained Application Protocol (CoAP)"; "RFC 7252 The Constrained Application Protocol (CoAP)";
} }
identity fid-coap-option-uri-host { identity fid-coap-option-uri-host {
base fid-coap-base-type; base fid-coap-option;
description description
"CoAP option URI-Host."; "CoAP option Uri-Host.";
reference reference
"RFC 7252 The Constrained Application Protocol (CoAP)"; "RFC 7252 The Constrained Application Protocol (CoAP)";
} }
identity fid-coap-option-etag { identity fid-coap-option-etag {
base fid-coap-base-type; base fid-coap-option;
description description
"CoAP option Etag."; "CoAP option ETag.";
reference reference
"RFC 7252 The Constrained Application Protocol (CoAP)"; "RFC 7252 The Constrained Application Protocol (CoAP)";
} }
identity fid-coap-option-if-none-match { identity fid-coap-option-if-none-match {
base fid-coap-base-type; base fid-coap-option;
description description
"CoAP option if-none-match."; "CoAP option if-none-match.";
reference reference
"RFC 7252 The Constrained Application Protocol (CoAP)"; "RFC 7252 The Constrained Application Protocol (CoAP)";
} }
identity fid-coap-option-observe { identity fid-coap-option-observe {
base fid-coap-base-type; base fid-coap-option;
description description
"CoAP option Observe."; "CoAP option Observe.";
reference reference
"RFC 7252 The Constrained Application Protocol (CoAP)"; "RFC 7252 The Constrained Application Protocol (CoAP)";
} }
identity fid-coap-option-uri-port { identity fid-coap-option-uri-port {
base fid-coap-base-type; base fid-coap-option;
description description
"CoAP option Uri-Port."; "CoAP option Uri-Port.";
reference reference
"RFC 7252 The Constrained Application Protocol (CoAP)"; "RFC 7252 The Constrained Application Protocol (CoAP)";
} }
identity fid-coap-option-location-path { identity fid-coap-option-location-path {
base fid-coap-base-type; base fid-coap-option;
description description
"CoAP option Location-Path."; "CoAP option Location-Path.";
reference reference
"RFC 7252 The Constrained Application Protocol (CoAP)"; "RFC 7252 The Constrained Application Protocol (CoAP)";
} }
identity fid-coap-option-uri-path { identity fid-coap-option-uri-path {
base fid-coap-base-type; base fid-coap-option;
description description
"CoAP option Uri-Path."; "CoAP option Uri-Path.";
reference reference
"RFC 7252 The Constrained Application Protocol (CoAP)"; "RFC 7252 The Constrained Application Protocol (CoAP)";
} }
identity fid-coap-option-content-format { identity fid-coap-option-content-format {
base fid-coap-base-type; base fid-coap-option;
description description
"CoAP option Content Format."; "CoAP option Content Format.";
reference reference
"RFC 7252 The Constrained Application Protocol (CoAP)"; "RFC 7252 The Constrained Application Protocol (CoAP)";
} }
identity fid-coap-option-max-age { identity fid-coap-option-max-age {
base fid-coap-base-type; base fid-coap-option;
description description
"CoAP option Max-Age."; "CoAP option Max-Age.";
reference reference
"RFC 7252 The Constrained Application Protocol (CoAP)"; "RFC 7252 The Constrained Application Protocol (CoAP)";
} }
identity fid-coap-option-uri-query { identity fid-coap-option-uri-query {
base fid-coap-base-type; base fid-coap-option;
description description
"CoAP option Uri-Query."; "CoAP option Uri-Query.";
reference reference
"RFC 7252 The Constrained Application Protocol (CoAP)"; "RFC 7252 The Constrained Application Protocol (CoAP)";
} }
identity fid-coap-option-accept { identity fid-coap-option-accept {
base fid-coap-base-type; base fid-coap-option;
description description
"CoAP option Accept."; "CoAP option Accept.";
reference reference
"RFC 7252 The Constrained Application Protocol (CoAP)"; "RFC 7252 The Constrained Application Protocol (CoAP)";
} }
identity fid-coap-option-location-query { identity fid-coap-option-location-query {
base fid-coap-base-type; base fid-coap-option;
description description
"CoAP option Location-Query."; "CoAP option Location-Query.";
reference reference
"RFC 7252 The Constrained Application Protocol (CoAP)"; "RFC 7252 The Constrained Application Protocol (CoAP)";
} }
identity fid-coap-option-block2 { identity fid-coap-option-block2 {
base fid-coap-base-type; base fid-coap-option;
description description
"CoAP option Block2."; "CoAP option Block2.";
reference reference
"RFC 7959 Block-Wise Transfers in the Constrained "RFC 7959 Block-Wise Transfers in the Constrained
Application Protocol (CoAP)"; Application Protocol (CoAP)";
} }
identity fid-coap-option-block1 { identity fid-coap-option-block1 {
base fid-coap-base-type; base fid-coap-option;
description description
"CoAP option Block1."; "CoAP option Block1.";
reference reference
"RFC 7959 Block-Wise Transfers in the Constrained "RFC 7959 Block-Wise Transfers in the Constrained
Application Protocol (CoAP)"; Application Protocol (CoAP)";
} }
identity fid-coap-option-size2 { identity fid-coap-option-size2 {
base fid-coap-base-type; base fid-coap-option;
description description
"CoAP option size2."; "CoAP option Size2.";
reference reference
"RFC 7959 Block-Wise Transfers in the Constrained "RFC 7959 Block-Wise Transfers in the Constrained
Application Protocol (CoAP)"; Application Protocol (CoAP)";
} }
identity fid-coap-option-proxy-uri { identity fid-coap-option-proxy-uri {
base fid-coap-base-type; base fid-coap-option;
description description
"CoAP option Proxy-Uri."; "CoAP option Proxy-Uri.";
reference reference
"RFC 7252 The Constrained Application Protocol (CoAP)"; "RFC 7252 The Constrained Application Protocol (CoAP)";
} }
identity fid-coap-option-proxy-scheme { identity fid-coap-option-proxy-scheme {
base fid-coap-base-type; base fid-coap-option;
description description
"CoAP option Proxy-scheme."; "CoAP option Proxy-Scheme.";
reference reference
"RFC 7252 The Constrained Application Protocol (CoAP)"; "RFC 7252 The Constrained Application Protocol (CoAP)";
} }
identity fid-coap-option-size1 { identity fid-coap-option-size1 {
base fid-coap-base-type; base fid-coap-option;
description description
"CoAP option Size1."; "CoAP option Size1.";
reference reference
"RFC 7252 The Constrained Application Protocol (CoAP)"; "RFC 7252 The Constrained Application Protocol (CoAP)";
} }
identity fid-coap-option-no-response { identity fid-coap-option-no-response {
base fid-coap-base-type; base fid-coap-option;
description description
"CoAP option No response."; "CoAP option No response.";
reference reference
"RFC 7967 Constrained Application Protocol (CoAP) "RFC 7967 Constrained Application Protocol (CoAP)
Option for No Server Response"; Option for No Server Response";
} }
identity fid-oscore-base-type { identity fid-oscore-base-type {
base fid-coap-type; base fid-coap-option;
description description
"OSCORE options (RFC8613) split in sub options."; "OSCORE options (RFC8613) split in suboptions.";
reference reference
"RFC 8824 Static Context Header Compression (SCHC) for the "RFC 8824 Static Context Header Compression (SCHC) for the
Constrained Application Protocol (CoAP)"; Constrained Application Protocol (CoAP)";
} }
identity fid-coap-option-oscore-flags { identity fid-coap-option-oscore-flags {
base fid-oscore-base-type; base fid-coap-option;
description description
"CoAP option oscore flags."; "CoAP option OSCORE flags.";
reference reference
"RFC 8824 Static Context Header Compression (SCHC) for the "RFC 8824 Static Context Header Compression (SCHC) for the
Constrained Application Protocol (CoAP) (see Constrained Application Protocol (CoAP) (see
section 6.4)"; Section 6.4)";
} }
identity fid-coap-option-oscore-piv { identity fid-coap-option-oscore-piv {
base fid-oscore-base-type; base fid-coap-option;
description description
"CoAP option oscore flags."; "CoAP option OSCORE flags.";
reference reference
"RFC 8824 Static Context Header Compression (SCHC) for the "RFC 8824 Static Context Header Compression (SCHC) for the
Constrained Application Protocol (CoAP) (see Constrained Application Protocol (CoAP) (see
section 6.4)"; Section 6.4)";
} }
identity fid-coap-option-oscore-kid { identity fid-coap-option-oscore-kid {
base fid-oscore-base-type; base fid-coap-option;
description description
"CoAP option oscore flags."; "CoAP option OSCORE flags.";
reference reference
"RFC 8824 Static Context Header Compression (SCHC) for the "RFC 8824 Static Context Header Compression (SCHC) for the
Constrained Application Protocol (CoAP) (see Constrained Application Protocol (CoAP) (see
section 6.4)"; Section 6.4)";
} }
identity fid-coap-option-oscore-kidctx { identity fid-coap-option-oscore-kidctx {
base fid-oscore-base-type; base fid-coap-option;
description description
"CoAP option oscore flags."; "CoAP option OSCORE flags.";
reference reference
"RFC 8824 Static Context Header Compression (SCHC) for the "RFC 8824 Static Context Header Compression (SCHC) for the
Constrained Application Protocol (CoAP)(see Constrained Application Protocol (CoAP)(see
section 6.4)"; Section 6.4)";
} }
//---------------------------------- //----------------------------------
// Field Length type definition // Field Length type definition
//---------------------------------- //----------------------------------
identity fl-base-type { identity fl-base-type {
description description
"Used to extend field length functions."; "Used to extend Field Length functions.";
} }
identity fl-variable { identity fl-variable {
base fl-base-type; base fl-base-type;
description description
"Residue length in Byte is sent as defined for CoAP."; "Residue length in bytes is sent as defined for CoAP.";
reference reference
"RFC 8824 Static Context Header Compression (SCHC) for the "RFC 8824 Static Context Header Compression (SCHC) for the
Constrained Application Protocol (CoAP) (see Constrained Application Protocol (CoAP) (see
section 5.3)"; Section 5.3)";
} }
identity fl-token-length { identity fl-token-length {
base fl-base-type; base fl-base-type;
description description
"Residue length in Byte is sent as defined for CoAP."; "Residue length in bytes is sent as defined for CoAP.";
reference reference
"RFC 8824 Static Context Header Compression (SCHC) for the "RFC 8824 Static Context Header Compression (SCHC) for the
Constrained Application Protocol (CoAP) (see Constrained Application Protocol (CoAP) (see
section 4.5)"; Section 4.5)";
} }
//--------------------------------- //---------------------------------
// Direction Indicator type // Direction Indicator type
//--------------------------------- //---------------------------------
identity di-base-type { identity di-base-type {
description description
"Used to extend direction indicators."; "Used to extend Direction Indicators.";
} }
identity di-bidirectional { identity di-bidirectional {
base di-base-type; base di-base-type;
description description
"Direction Indication of bidirectionality."; "Direction Indicator of bidirectionality.";
reference reference
"RFC 8724 SCHC: Generic Framework for Static Context "RFC 8724 SCHC: Generic Framework for Static Context
Header Compression and Fragmentation (see Header Compression and Fragmentation (see
section 7.1.)"; Section 7.1)";
} }
identity di-up { identity di-up {
base di-base-type; base di-base-type;
description description
"Direction Indication of uplink."; "Direction Indicator of uplink.";
reference reference
"RFC 8724 SCHC: Generic Framework for Static Context "RFC 8724 SCHC: Generic Framework for Static Context
Header Compression and Fragmentation (see Header Compression and Fragmentation (see
section 7.1)."; Section 7.1)";
} }
identity di-down { identity di-down {
base di-base-type; base di-base-type;
description description
"Direction Indication of downlink."; "Direction Indicator of downlink.";
reference reference
"RFC 8724 SCHC: Generic Framework for Static Context "RFC 8724 SCHC: Generic Framework for Static Context
Header Compression and Fragmentation (see Header Compression and Fragmentation (see
section 7.1)."; Section 7.1)";
} }
//---------------------------------- //----------------------------------
// Matching Operator type definition // Matching Operator type definition
//---------------------------------- //----------------------------------
identity mo-base-type { identity mo-base-type {
description description
"Matching Operator: used in the rule selection process "Matching Operator: used in the Rule selection process
to check is a Target Value matches the field's value."; to check if a Target Value matches the field's value.";
reference reference
"RFC 8724 SCHC: Generic Framework for Static Context "RFC 8724 SCHC: Generic Framework for Static Context
Header Compression and Fragmentation (see* Header Compression and Fragmentation (see
section 7.2)."; Section 7.2)";
} }
identity mo-equal { identity mo-equal {
base mo-base-type; base mo-base-type;
description description
"equal MO."; "equal MO.";
reference reference
"RFC 8724 SCHC: Generic Framework for Static Context "RFC 8724 SCHC: Generic Framework for Static Context
Header Compression and Fragmentation (see Header Compression and Fragmentation (see
section 7.3)."; Section 7.3)";
} }
identity mo-ignore { identity mo-ignore {
base mo-base-type; base mo-base-type;
description description
"ignore MO."; "ignore MO.";
reference reference
"RFC 8724 SCHC: Generic Framework for Static Context "RFC 8724 SCHC: Generic Framework for Static Context
Header Compression and Fragmentation (see Header Compression and Fragmentation (see
section 7.3)."; Section 7.3)";
} }
identity mo-msb { identity mo-msb {
base mo-base-type; base mo-base-type;
description description
"MSB MO."; "MSB MO.";
reference reference
"RFC 8724 SCHC: Generic Framework for Static Context "RFC 8724 SCHC: Generic Framework for Static Context
Header Compression and Fragmentation (see Header Compression and Fragmentation (see
section 7.3)."; Section 7.3)";
} }
identity mo-match-mapping { identity mo-match-mapping {
base mo-base-type; base mo-base-type;
description description
"match-mapping MO."; "match-mapping MO.";
reference reference
"RFC 8724 SCHC: Generic Framework for Static Context "RFC 8724 SCHC: Generic Framework for Static Context
Header Compression and Fragmentation (see Header Compression and Fragmentation (see
section 7.3)."; Section 7.3)";
} }
//------------------------------ //------------------------------
// CDA type definition // CDA type definition
//------------------------------ //------------------------------
identity cda-base-type { identity cda-base-type {
description description
"Compression Decompression Actions. Specify the action to "Compression Decompression Actions. Specify the action to
be applied to the field's value in a specific rule."; be applied to the field's value in a specific Rule.";
reference reference
"RFC 8724 SCHC: Generic Framework for Static Context "RFC 8724 SCHC: Generic Framework for Static Context
Header Compression and Fragmentation (see Header Compression and Fragmentation (see
section 7.2)."; Section 7.2)";
} }
identity cda-not-sent { identity cda-not-sent {
base cda-base-type; base cda-base-type;
description description
"not-sent CDA."; "not-sent CDA.";
reference reference
"RFC 8724 SCHC: Generic Framework for Static Context "RFC 8724 SCHC: Generic Framework for Static Context
Header Compression and Fragmentation (see Header Compression and Fragmentation (see
section 7.4)."; Section 7.4)";
} }
identity cda-value-sent { identity cda-value-sent {
base cda-base-type; base cda-base-type;
description description
"value-sent CDA."; "value-sent CDA.";
reference reference
"RFC 8724 SCHC: Generic Framework for Static Context "RFC 8724 SCHC: Generic Framework for Static Context
Header Compression and Fragmentation (see Header Compression and Fragmentation (see
section 7.4)."; Section 7.4)";
} }
identity cda-lsb { identity cda-lsb {
base cda-base-type; base cda-base-type;
description description
"LSB CDA."; "Least Significant Bit (LSB) CDA.";
reference reference
"RFC 8724 SCHC: Generic Framework for Static Context "RFC 8724 SCHC: Generic Framework for Static Context
Header Compression and Fragmentation (see Header Compression and Fragmentation (see
section 7.4)."; Section 7.4)";
} }
identity cda-mapping-sent { identity cda-mapping-sent {
base cda-base-type; base cda-base-type;
description description
"mapping-sent CDA."; "mapping-sent CDA.";
reference reference
"RFC 8724 SCHC: Generic Framework for Static Context "RFC 8724 SCHC: Generic Framework for Static Context
Header Compression and Fragmentation (see Header Compression and Fragmentation (see
section 7.4)."; Section 7.4)";
} }
identity cda-compute { identity cda-compute {
base cda-base-type; base cda-base-type;
description description
"compute-* CDA."; "compute-* CDA.";
reference reference
"RFC 8724 SCHC: Generic Framework for Static Context "RFC 8724 SCHC: Generic Framework for Static Context
Header Compression and Fragmentation (see Header Compression and Fragmentation (see
section 7.4)."; Section 7.4)";
} }
identity cda-deviid { identity cda-deviid {
base cda-base-type; base cda-base-type;
description description
"DevIID CDA."; "DevIID CDA.";
reference reference
"RFC 8724 SCHC: Generic Framework for Static Context "RFC 8724 SCHC: Generic Framework for Static Context
Header Compression and Fragmentation (see Header Compression and Fragmentation (see
section 7.4)."; Section 7.4)";
} }
identity cda-appiid { identity cda-appiid {
base cda-base-type; base cda-base-type;
description description
"AppIID CDA."; "Application Interface Identifier (AppIID) CDA.";
reference reference
"RFC 8724 SCHC: Generic Framework for Static Context "RFC 8724 SCHC: Generic Framework for Static Context
Header Compression and Fragmentation (see Header Compression and Fragmentation (see
section 7.4)."; Section 7.4)";
} }
// -- type definition // -- type definition
typedef fid-type { typedef fid-type {
type identityref { type identityref {
base fid-base-type; base fid-base-type;
} }
description description
"Field ID generic type."; "Field ID generic type.";
reference reference
"RFC 8724 SCHC: Generic Framework for Static Context Header "RFC 8724 SCHC: Generic Framework for Static Context Header
Compression and Fragmentation"; Compression and Fragmentation";
} }
typedef fl-type { typedef fl-type {
type union { type identityref {
type uint64 { base fl-base-type;
range 1..max;
}
type identityref {
base fl-base-type;
}
} }
description description
"Field length either a positive integer expressing the size in "Function used to indicate Field Length.";
bits or a function defined through an identityref.";
reference reference
"RFC 8724 SCHC: Generic Framework for Static Context Header "RFC 8724 SCHC: Generic Framework for Static Context Header
Compression and Fragmentation"; Compression and Fragmentation";
} }
typedef di-type { typedef di-type {
type identityref { type identityref {
base di-base-type; base di-base-type;
} }
description description
"Direction in LPWAN network, up when emitted by the device, "Direction in LPWAN network: up when emitted by the device,
down when received by the device, bi when emitted or down when received by the device, or bi when emitted or
received by the device."; received by the device.";
reference reference
"RFC 8724 SCHC: Generic Framework for Static Context Header "RFC 8724 SCHC: Generic Framework for Static Context Header
Compression and Fragmentation"; Compression and Fragmentation";
} }
typedef mo-type { typedef mo-type {
type identityref { type identityref {
base mo-base-type; base mo-base-type;
} }
description description
"Matching Operator (MO) to compare fields values with "Matching Operator (MO) to compare field values with
target values."; Target Values.";
reference reference
"RFC 8724 SCHC: Generic Framework for Static Context Header "RFC 8724 SCHC: Generic Framework for Static Context Header
Compression and Fragmentation"; Compression and Fragmentation";
} }
typedef cda-type { typedef cda-type {
type identityref { type identityref {
base cda-base-type; base cda-base-type;
} }
description description
"Compression Decompression Action to compression or "Compression Decompression Action to compress or
decompress a field."; decompress a field.";
reference reference
"RFC 8724 SCHC: Generic Framework for Static Context Header "RFC 8724 SCHC: Generic Framework for Static Context Header
Compression and Fragmentation"; Compression and Fragmentation";
} }
// -- FRAGMENTATION TYPE // -- FRAGMENTATION TYPE
// -- fragmentation modes // -- fragmentation modes
identity fragmentation-mode-base-type { identity fragmentation-mode-base-type {
skipping to change at page 33, line 26 skipping to change at line 1512
reference reference
"RFC 8724 SCHC: Generic Framework for Static Context Header "RFC 8724 SCHC: Generic Framework for Static Context Header
Compression and Fragmentation"; Compression and Fragmentation";
} }
typedef fragmentation-mode-type { typedef fragmentation-mode-type {
type identityref { type identityref {
base fragmentation-mode-base-type; base fragmentation-mode-base-type;
} }
description description
"Define the type used for fragmentation mode in rules."; "Define the type used for fragmentation mode in Rules.";
} }
// -- Ack behavior // -- Ack behavior
identity ack-behavior-base-type { identity ack-behavior-base-type {
description description
"Define when to send an Acknowledgment ."; "Define when to send an Acknowledgment.";
reference reference
"RFC 8724 SCHC: Generic Framework for Static Context Header "RFC 8724 SCHC: Generic Framework for Static Context Header
Compression and Fragmentation"; Compression and Fragmentation";
} }
identity ack-behavior-after-all-0 { identity ack-behavior-after-all-0 {
base ack-behavior-base-type; base ack-behavior-base-type;
description description
"Fragmentation expects Ack after sending All-0 fragment."; "Fragmentation expects ACK after sending All-0 fragment.";
} }
identity ack-behavior-after-all-1 { identity ack-behavior-after-all-1 {
base ack-behavior-base-type; base ack-behavior-base-type;
description description
"Fragmentation expects Ack after sending All-1 fragment."; "Fragmentation expects ACK after sending All-1 fragment.";
} }
identity ack-behavior-by-layer2 { identity ack-behavior-by-layer2 {
base ack-behavior-base-type; base ack-behavior-base-type;
description description
"Layer 2 defines when to send an Ack."; "Layer 2 defines when to send an ACK.";
} }
typedef ack-behavior-type { typedef ack-behavior-type {
type identityref { type identityref {
base ack-behavior-base-type; base ack-behavior-base-type;
} }
description description
"Define the type used for Ack behavior in rules."; "Define the type used for ACK behavior in Rules.";
} }
// -- All-1 with data types // -- All-1 with data types
identity all-1-data-base-type { identity all-1-data-base-type {
description description
"Type to define when to send an Acknowledgment message."; "Type to define when to send an Acknowledgment message.";
reference reference
"RFC 8724 SCHC: Generic Framework for Static Context Header "RFC 8724 SCHC: Generic Framework for Static Context Header
Compression and Fragmentation"; Compression and Fragmentation";
skipping to change at page 34, line 50 skipping to change at line 1584
base all-1-data-base-type; base all-1-data-base-type;
description description
"Fragmentation process chooses to send tiles or not in All-1."; "Fragmentation process chooses to send tiles or not in All-1.";
} }
typedef all-1-data-type { typedef all-1-data-type {
type identityref { type identityref {
base all-1-data-base-type; base all-1-data-base-type;
} }
description description
"Define the type used for All-1 format in rules."; "Define the type used for All-1 format in Rules.";
} }
// -- RCS algorithm types // -- RCS algorithm types
identity rcs-algorithm-base-type { identity rcs-algorithm-base-type {
description description
"Identify which algorithm is used to compute RCS. "Identify which algorithm is used to compute RCS.
The algorithm also defines the size of the RCS field."; The algorithm also defines the size of the RCS field.";
reference reference
"RFC 8724 SCHC: Generic Framework for Static Context Header "RFC 8724 SCHC: Generic Framework for Static Context Header
Compression and Fragmentation"; Compression and Fragmentation";
} }
identity rcs-crc32 { identity rcs-crc32 {
base rcs-algorithm-base-type; base rcs-algorithm-base-type;
description description
"CRC 32 defined as default RCS in RFC8724. This RCS is "CRC32 defined as default RCS in RFC 8724. This RCS is
4 bytes long."; 4 bytes long.";
reference reference
"RFC 8724 SCHC: Generic Framework for Static Context Header "RFC 8724 SCHC: Generic Framework for Static Context Header
Compression and Fragmentation"; Compression and Fragmentation";
} }
typedef rcs-algorithm-type { typedef rcs-algorithm-type {
type identityref { type identityref {
base rcs-algorithm-base-type; base rcs-algorithm-base-type;
} }
description description
"Define the type for RCS algorithm in rules."; "Define the type for RCS algorithm in Rules.";
} }
// -------- RULE ENTRY DEFINITION ------------ // -------- RULE ENTRY DEFINITION ------------
grouping tv-struct { grouping tv-struct {
description description
"Defines the target value element. If the header field "Defines the Target Value element. If the header field
contains a text, the binary sequence uses the same encoding. contains a text, the binary sequence uses the same encoding.
field-id allows the conversion to the appropriate type."; field-id allows the conversion to the appropriate type.";
leaf index { leaf index {
type uint16; type uint16;
description description
"Index gives the position in the matching-list. If only one "Index gives the position in the matching list. If only one
element is present, index is 0. Otherwise, index is the element is present, index is 0. Otherwise, index is the
the order in the matching list, starting at 0."; order in the matching list, starting at 0.";
} }
leaf value { leaf value {
type binary; type binary;
description description
"Target Value content as an untyped binary value."; "Target Value content as an untyped binary value.";
} }
reference reference
"RFC 8724 SCHC: Generic Framework for Static Context Header "RFC 8724 SCHC: Generic Framework for Static Context Header
Compression and Fragmentation"; Compression and Fragmentation";
} }
grouping compression-rule-entry { grouping compression-rule-entry {
description description
"These entries defines a compression entry (i.e. a line) "These entries define a compression entry (i.e., a line),
as defined in RFC 8724. as defined in RFC 8724.
+-------+--+--+--+------------+-----------------+---------------+ +-------+--+--+--+------------+-----------------+---------------+
|Field 1|FL|FP|DI|Target Value|Matching Operator|Comp/Decomp Act| |Field 1|FL|FP|DI|Target Value|Matching Operator|Comp/Decomp Act|
+-------+--+--+--+------------+-----------------+---------------+ +-------+--+--+--+------------+-----------------+---------------+
An entry in a compression Rule is composed of 7 elements:
An entry in a compression rule is composed of 7 elements: - Field ID: the header field to be compressed
- Field ID: The header field to be compressed. - Field Length : either a positive integer or a function
- Field Length : Either a positive integer of a function. - Field Position: a positive (and possibly equal to 0)
- Field Position: A positive (and possibly equal to 0) integer
integer. - Direction Indicator: an indication in which direction the
- Direction Indicator: An indication in which direction compression and decompression process is effective
compression and decompression process is effective. - Target Value: a value against which the header field is
- Target value: A value against which the header Field is compared
compared. - Matching Operator: the comparison operation and optional
- Matching Operator: The comparison operation and optional associate parameters
associate parameters. - Comp./Decomp. Action: the compression or decompression
- Comp./Decomp. Action: The compression or decompression action and optional parameters
action, and optional parameters.
"; ";
leaf field-id { leaf field-id {
type schc:fid-type; type schc:fid-type;
mandatory true; mandatory true;
description description
"Field ID, identify a field in the header with a YANG "Field ID, identify a field in the header with a YANG
identity reference."; identity reference.";
} }
leaf field-length { leaf field-length {
type union {
type uint8;
type schc:fl-type; type schc:fl-type;
}
mandatory true; mandatory true;
description description
"Field Length, expressed in number of bits if the length is "Field Length, expressed in number of bits if the length is
known when the Rule is created or through a specific known when the Rule is created or through a specific
function if the length is variable."; function if the length is variable.";
} }
leaf field-position { leaf field-position {
type uint8; type uint8;
mandatory true; mandatory true;
description description
"Field position in the header is an integer. Position 1 "Field Position in the header is an integer. Position 1
matches the first occurrence of a field in the header, matches the first occurrence of a field in the header,
while incremented position values match subsequent while incremented position values match subsequent
occurrences. occurrences.
Position 0 means that this entry matches a field Position 0 means that this entry matches a field
irrespective of its position of occurrence in the irrespective of its position of occurrence in the
header. header.
Be aware that the decompressed header may have Be aware that the decompressed header may have
position-0 fields ordered differently than they position-0 fields ordered differently than they
appeared in the original packet."; appeared in the original packet.";
} }
leaf direction-indicator { leaf direction-indicator {
type schc:di-type; type schc:di-type;
mandatory true; mandatory true;
description description
"Direction Indicator, indicate if this field must be "Direction Indicator, indicate if this field must be
considered for rule selection or ignored based on the considered for Rule selection or ignored based on the
direction (bi directionnal, only uplink, or only direction (bidirectional, only uplink, or only
downlink)."; downlink).";
} }
list target-value { list target-value {
key "index"; key "index";
uses tv-struct; uses tv-struct;
description description
"A list of value to compare with the header field value. "A list of values to compare with the header field value.
If target value is a singleton, position must be 0. If Target Value is a singleton, position must be 0.
For use as a matching list for the mo-match-mapping matching For use as a matching list for the mo-match-mapping Matching
operator, index should take consecutive values starting Operator, index should take consecutive values starting
from 0."; from 0.";
} }
leaf matching-operator { leaf matching-operator {
type schc:mo-type; type schc:mo-type;
must "../target-value or derived-from-or-self(., must "../target-value or derived-from-or-self(.,
'mo-ignore')" { 'mo-ignore')" {
error-message error-message
"mo-equal, mo-msb and mo-match-mapping need target-value"; "mo-equal, mo-msb, and mo-match-mapping need target-value";
description description
"target-value is not required for mo-ignore."; "target-value is not required for mo-ignore.";
} }
must "not (derived-from-or-self(., 'mo-msb')) or must "not (derived-from-or-self(., 'mo-msb')) or
../matching-operator-value" { ../matching-operator-value" {
error-message "mo-msb requires length value"; error-message "mo-msb requires length value";
} }
mandatory true; mandatory true;
description description
"MO: Matching Operator."; "MO: Matching Operator.";
reference reference
"RFC 8724 SCHC: Generic Framework for Static Context Header "RFC 8724 SCHC: Generic Framework for Static Context Header
Compression and Fragmentation (see Section 7.3)."; Compression and Fragmentation (see Section 7.3)";
} }
list matching-operator-value { list matching-operator-value {
key "index"; key "index";
uses tv-struct; uses tv-struct;
description description
"Matching Operator Arguments, based on TV structure to allow "Matching Operator Arguments, based on TV structure to allow
several arguments. several arguments.
In RFC 8724, only the MSB matching operator needs arguments In RFC 8724, only the MSB Matching Operator needs arguments
(a single argument, which is the number of most significant (a single argument, which is the number of most significant
bits to be matched)."; bits to be matched).";
} }
leaf comp-decomp-action { leaf comp-decomp-action {
type schc:cda-type; type schc:cda-type;
must "../target-value or must "../target-value or
derived-from-or-self(., 'cda-value-sent') or derived-from-or-self(., 'cda-value-sent') or
derived-from-or-self(., 'cda-compute') or derived-from-or-self(., 'cda-compute') or
derived-from-or-self(., 'cda-appiid') or derived-from-or-self(., 'cda-appiid') or
derived-from-or-self(., 'cda-deviid')" { derived-from-or-self(., 'cda-deviid')" {
error-message error-message
"cda-not-sent, cda-lsb, cda-mapping-sent need "cda-not-sent, cda-lsb, and cda-mapping-sent need
target-value"; target-value";
description description
"target-value is not required for some CDA."; "target-value is not required for some CDA.";
} }
mandatory true; mandatory true;
description description
"CDA: Compression Decompression Action."; "CDA: Compression Decompression Action.";
reference reference
"RFC 8724 SCHC: Generic Framework for Static Context Header "RFC 8724 SCHC: Generic Framework for Static Context Header
Compression and Fragmentation (see section 7.4)"; Compression and Fragmentation (see Section 7.4)";
} }
list comp-decomp-action-value { list comp-decomp-action-value {
key "index"; key "index";
uses tv-struct; uses tv-struct;
description description
"CDA arguments, based on a TV structure, in order to allow "CDA arguments, based on a TV structure, in order to allow
for several arguments. The CDAs specified in RFC 8724 for several arguments. The CDAs specified in RFC 8724
require no argument."; require no argument.";
} }
} }
// --Rule nature // --Rule nature
identity nature-base-type { identity nature-base-type {
description description
"A rule, identified by its RuleID, are used for a single "A Rule, identified by its RuleID, is used for a single
purpose. RFC 8724 defines 2 natures: purpose. RFC 8724 defines 3 natures:
compression, no-compression, and fragmentation.";
compression, no compression and fragmentation.";
reference reference
"RFC 8724 SCHC: Generic Framework for Static Context Header "RFC 8724 SCHC: Generic Framework for Static Context Header
Compression and Fragmentation (see section 6)."; Compression and Fragmentation (see Section 6)";
} }
identity nature-compression { identity nature-compression {
base nature-base-type; base nature-base-type;
description description
"Identify a compression rule."; "Identify a compression Rule.";
reference reference
"RFC 8724 SCHC: Generic Framework for Static Context Header "RFC 8724 SCHC: Generic Framework for Static Context Header
Compression and Fragmentation (see section 6)."; Compression and Fragmentation (see Section 6)";
} }
identity nature-no-compression { identity nature-no-compression {
base nature-base-type; base nature-base-type;
description description
"Identify a no compression rule."; "Identify a no-compression Rule.";
reference reference
"RFC 8724 SCHC: Generic Framework for Static Context Header "RFC 8724 SCHC: Generic Framework for Static Context Header
Compression and Fragmentation (see section 6)."; Compression and Fragmentation (see Section 6)";
} }
identity nature-fragmentation { identity nature-fragmentation {
base nature-base-type; base nature-base-type;
description description
"Identify a fragmentation rule."; "Identify a fragmentation Rule.";
reference reference
"RFC 8724 SCHC: Generic Framework for Static Context Header "RFC 8724 SCHC: Generic Framework for Static Context Header
Compression and Fragmentation (see section 6)."; Compression and Fragmentation (see Section 6)";
} }
typedef nature-type { typedef nature-type {
type identityref { type identityref {
base nature-base-type; base nature-base-type;
} }
description description
"defines the type to indicate the nature of the rule."; "Defines the type to indicate the nature of the Rule.";
} }
grouping compression-content { grouping compression-content {
list entry { list entry {
must "derived-from-or-self(../rule-nature, must "derived-from-or-self(../rule-nature,
'nature-compression')" { 'nature-compression')" {
error-message "Rule nature must be compression"; error-message "Rule nature must be compression";
} }
key "field-id field-position direction-indicator"; key "field-id field-position direction-indicator";
uses compression-rule-entry; uses compression-rule-entry;
description description
"A compression rule is a list of rule entries, each "A compression Rule is a list of Rule entries, each
describing a header field. An entry is identified describing a header field. An entry is identified
through a field-id, its position in the packet, and through a field-id, its position in the packet, and
its direction."; its direction.";
} }
description description
"Define a compression rule composed of a list of entries."; "Define a compression Rule composed of a list of entries.";
reference reference
"RFC 8724 SCHC: Generic Framework for Static Context Header "RFC 8724 SCHC: Generic Framework for Static Context Header
Compression and Fragmentation"; Compression and Fragmentation";
} }
grouping fragmentation-content { grouping fragmentation-content {
description description
"This grouping defines the fragmentation parameters for "This grouping defines the fragmentation parameters for
all the modes (No-ACK, ACK-Always and ACK-on-Error) specified all the modes (No ACK, ACK Always, and ACK on Error) specified
in RFC 8724."; in RFC 8724.";
leaf fragmentation-mode { leaf fragmentation-mode {
type schc:fragmentation-mode-type; type schc:fragmentation-mode-type;
must "derived-from-or-self(../rule-nature, must "derived-from-or-self(../rule-nature,
'nature-fragmentation')" { 'nature-fragmentation')" {
error-message "Rule nature must be fragmentation"; error-message "Rule nature must be fragmentation";
} }
mandatory true; mandatory true;
description description
"Which fragmentation mode is used (No-Ack, ACK-Always, "Which fragmentation mode is used (No ACK, ACK Always, or
ACK-on-Error)."; ACK on Error).";
} }
leaf l2-word-size { leaf l2-word-size {
type uint8; type uint8;
default "8"; default "8";
description description
"Size, in bits, of the layer 2 word."; "Size, in bits, of the Layer 2 Word.";
} }
leaf direction { leaf direction {
type schc:di-type; type schc:di-type;
must "derived-from-or-self(., 'di-up') or must "derived-from-or-self(., 'di-up') or
derived-from-or-self(., 'di-down')" { derived-from-or-self(., 'di-down')" {
error-message error-message
"Direction for fragmentation rules are up or down."; "Direction for fragmentation Rules are up or down.";
} }
mandatory true; mandatory true;
description description
"MUST be up or down, bidirectional MUST NOT be used."; "MUST be up or down, bidirectional MUST NOT be used.";
} }
// SCHC Frag header format // SCHC Frag header format
leaf dtag-size { leaf dtag-size {
type uint8; type uint8;
default "0"; default "0";
description description
"Size, in bits, of the DTag field (T variable from "Size, in bits, of the DTag field (T variable from
RFC8724)."; RFC 8724).";
} }
leaf w-size { leaf w-size {
when "derived-from-or-self(../fragmentation-mode, when "derived-from-or-self(../fragmentation-mode,
'fragmentation-mode-ack-on-error') 'fragmentation-mode-ack-on-error')
or or
derived-from-or-self(../fragmentation-mode, derived-from-or-self(../fragmentation-mode,
'fragmentation-mode-ack-always') "; 'fragmentation-mode-ack-always') ";
type uint8; type uint8;
description description
"Size, in bits, of the window field (M variable from "Size, in bits, of the window field (M variable from
RFC8724)."; RFC 8724).";
} }
leaf fcn-size { leaf fcn-size {
type uint8; type uint8;
mandatory true; mandatory true;
description description
"Size, in bits, of the FCN field (N variable from RFC8724)."; "Size, in bits, of the FCN field (N variable from
RFC 8724).";
} }
leaf rcs-algorithm { leaf rcs-algorithm {
type rcs-algorithm-type; type rcs-algorithm-type;
default "schc:rcs-crc32"; default "schc:rcs-crc32";
description description
"Algorithm used for RCS. The algorithm specifies the RCS "Algorithm used for RCS. The algorithm specifies the RCS
size."; size.";
} }
// SCHC fragmentation protocol parameters // SCHC fragmentation protocol parameters
leaf maximum-packet-size { leaf maximum-packet-size {
type uint16; type uint16;
default "1280"; default "1280";
description description
"When decompression is done, packet size must not "When decompression is done, packet size must not
strictly exceed this limit, expressed in bytes."; strictly exceed this limit, expressed in bytes.";
} }
leaf window-size { leaf window-size {
type uint16; type uint16;
description description
"By default, if not specified 2^w-size - 1. Should not exceed "By default, if not specified, the FCN value is 2^w-size - 1.
this value. Possible FCN values are between 0 and This value should not be exceeded. Possible FCN values
window-size - 1."; are between 0 and window-size - 1.";
} }
leaf max-interleaved-frames { leaf max-interleaved-frames {
type uint8; type uint8;
default "1"; default "1";
description description
"Maximum of simultaneously fragmented frames. Maximum value "Maximum of simultaneously fragmented frames. Maximum value
is 2^dtag-size. All DTAG values can be used, but more than is 2^dtag-size. All DTag values can be used, but more than
max-interleaved-frames MUST NOT be active at any time"; max-interleaved-frames MUST NOT be active at any time.";
} }
container inactivity-timer { container inactivity-timer {
leaf ticks-duration { leaf ticks-duration {
type uint8; type uint8;
default "20"; default "20";
description description
"Duration of one tick in micro-seconds: "Duration of one tick in microseconds:
2^ticks-duration/10^6 = 1.048s."; 2^ticks-duration/10^6 = 1.048s.";
} }
leaf ticks-numbers { leaf ticks-numbers {
type uint16 { type uint16 {
range "0..max"; range "0..max";
} }
description description
"Timer duration = ticks-numbers*2^ticks-duration / 10^6."; "Timer duration = ticks-numbers*2^ticks-duration / 10^6.";
} }
description description
"Duration is seconds of the inactivity timer, 0 indicates "Duration in seconds of the Inactivity Timer; 0 indicates
that the timer is disabled. that the timer is disabled.
Allows a precision from micro-second to year by sending the Allows a precision from microsecond to year by sending the
tick-duration value. For instance: tick-duration value. For instance:
tick-duration / smallest value highest value tick-duration: smallest value <-> highest value
v
20: 00y 000d 00h 00m 01s.048575<->00y 000d 19h 05m 18s.428159
21: 00y 000d 00h 00m 02s.097151<->00y 001d 14h 10m 36s.856319
22: 00y 000d 00h 00m 04s.194303<->00y 003d 04h 21m 13s.712639
23: 00y 000d 00h 00m 08s.388607<->00y 006d 08h 42m 27s.425279
24: 00y 000d 00h 00m 16s.777215<->00y 012d 17h 24m 54s.850559
25: 00y 000d 00h 00m 33s.554431<->00y 025d 10h 49m 49s.701119
Note that the smallest value is also the incrementation step, 20: 00y 000d 00h 00m 01s.048575<->00y 000d 19h 05m 18s.428159
so the timer precision."; 21: 00y 000d 00h 00m 02s.097151<->00y 001d 14h 10m 36s.856319
22: 00y 000d 00h 00m 04s.194303<->00y 003d 04h 21m 13s.712639
23: 00y 000d 00h 00m 08s.388607<->00y 006d 08h 42m 27s.425279
24: 00y 000d 00h 00m 16s.777215<->00y 012d 17h 24m 54s.850559
25: 00y 000d 00h 00m 33s.554431<->00y 025d 10h 49m 49s.701119
Note that the smallest value is also the incrementation
step.";
} }
container retransmission-timer { container retransmission-timer {
leaf ticks-duration { leaf ticks-duration {
type uint8; type uint8;
default "20"; default "20";
description description
"Duration of one tick in micro-seconds: "Duration of one tick in microseconds:
2^ticks-duration/10^6 = 1.048s."; 2^ticks-duration/10^6 = 1.048s.";
} }
leaf ticks-numbers { leaf ticks-numbers {
type uint16 { type uint16 {
range "1..max"; range "1..max";
} }
description description
"Timer duration = ticks-numbers*2^ticks-duration / 10^6."; "Timer duration = ticks-numbers*2^ticks-duration / 10^6.";
} }
when "derived-from-or-self(../fragmentation-mode, when "derived-from-or-self(../fragmentation-mode,
'fragmentation-mode-ack-on-error') 'fragmentation-mode-ack-on-error')
or or
derived-from-or-self(../fragmentation-mode, derived-from-or-self(../fragmentation-mode,
'fragmentation-mode-ack-always') "; 'fragmentation-mode-ack-always') ";
description description
"Duration in seconds of the retransmission timer. "Duration in seconds of the Retransmission Timer.
See inactivity timer."; See the Inactivity Timer.";
} }
leaf max-ack-requests { leaf max-ack-requests {
when "derived-from-or-self(../fragmentation-mode, when "derived-from-or-self(../fragmentation-mode,
'fragmentation-mode-ack-on-error') 'fragmentation-mode-ack-on-error')
or or
derived-from-or-self(../fragmentation-mode, derived-from-or-self(../fragmentation-mode,
'fragmentation-mode-ack-always') "; 'fragmentation-mode-ack-always') ";
type uint8 { type uint8 {
range "1..max"; range "1..max";
} }
skipping to change at page 43, line 44 skipping to change at line 2010
} }
choice mode { choice mode {
case no-ack; case no-ack;
case ack-always; case ack-always;
case ack-on-error { case ack-on-error {
leaf tile-size { leaf tile-size {
when "derived-from-or-self(../fragmentation-mode, when "derived-from-or-self(../fragmentation-mode,
'fragmentation-mode-ack-on-error')"; 'fragmentation-mode-ack-on-error')";
type uint8; type uint8;
description description
"Size, in bits, of tiles. If not specified or set to 0, "Size, in bits, of tiles. If not specified or set to 0,
tiles fill the fragment."; tiles fill the fragment.";
} }
leaf tile-in-all-1 { leaf tile-in-all-1 {
when "derived-from-or-self(../fragmentation-mode, when "derived-from-or-self(../fragmentation-mode,
'fragmentation-mode-ack-on-error')"; 'fragmentation-mode-ack-on-error')";
type schc:all-1-data-type; type schc:all-1-data-type;
description description
"Defines whether the sender and receiver expect a tile in "Defines whether the sender and receiver expect a tile in
All-1 fragments or not, or if it is left to the sender's All-1 fragments or not, or if it is left to the sender's
choice."; choice.";
} }
leaf ack-behavior { leaf ack-behavior {
when "derived-from-or-self(../fragmentation-mode, when "derived-from-or-self(../fragmentation-mode,
'fragmentation-mode-ack-on-error')"; 'fragmentation-mode-ack-on-error')";
type schc:ack-behavior-type; type schc:ack-behavior-type;
description description
"Sender behavior to acknowledge, after All-0, All-1 or "Sender behavior to acknowledge, after All-0 or All-1 or
when the LPWAN allows it."; when the LPWAN allows it.";
} }
} }
description description
"RFC 8724 defines 3 fragmentation modes."; "RFC 8724 defines 3 fragmentation modes.";
} }
reference reference
"RFC 8724 SCHC: Generic Framework for Static Context Header "RFC 8724 SCHC: Generic Framework for Static Context Header
Compression and Fragmentation"; Compression and Fragmentation";
} }
// Define rule ID. Rule ID is composed of a RuleID value and a // Define RuleID. RuleID is composed of a RuleID value and a
// Rule ID Length // RuleID length
grouping rule-id-type { grouping rule-id-type {
leaf rule-id-value { leaf rule-id-value {
type uint32; type uint32;
description description
"Rule ID value, this value must be unique, considering its "RuleID value. This value must be unique, considering its
length."; length.";
} }
leaf rule-id-length { leaf rule-id-length {
type uint8 { type uint8 {
range "0..32"; range "0..32";
} }
description description
"Rule ID length, in bits. The value 0 is for implicit "RuleID length, in bits. The value 0 is for implicit
rules."; Rules.";
} }
description description
"A rule ID is composed of a value and a length, expressed in "A RuleID is composed of a value and a length, expressed in
bits."; bits.";
reference reference
"RFC 8724 SCHC: Generic Framework for Static Context Header "RFC 8724 SCHC: Generic Framework for Static Context Header
Compression and Fragmentation"; Compression and Fragmentation";
} }
// SCHC table for a specific device. // SCHC table for a specific device.
container schc { container schc {
list rule { list rule {
key "rule-id-value rule-id-length"; key "rule-id-value rule-id-length";
uses rule-id-type; uses rule-id-type;
leaf rule-nature { leaf rule-nature {
type nature-type; type nature-type;
mandatory true; mandatory true;
description description
"Specify the rule's nature."; "Specify the Rule's nature.";
} }
choice nature { choice nature {
case fragmentation { case fragmentation {
if-feature "fragmentation"; if-feature "fragmentation";
uses fragmentation-content; uses fragmentation-content;
} }
case compression { case compression {
if-feature "compression"; if-feature "compression";
uses compression-content; uses compression-content;
} }
description description
"A rule is for compression, for no-compression or for "A Rule is for compression, for no-compression, or for
fragmentation."; fragmentation.";
} }
description description
"Set of rules compression, no compression or fragmentation "Set of compression, no-compression, or fragmentation
rules identified by their rule-id."; Rules identified by their rule-id.";
} }
description description
"A SCHC set of rules is composed of a list of rules which are "A SCHC set of Rules is composed of a list of Rules that are
used for compression, no-compression or fragmentation."; used for compression, no-compression, or fragmentation.";
reference reference
"RFC 8724 SCHC: Generic Framework for Static Context Header "RFC 8724 SCHC: Generic Framework for Static Context Header
Compression and Fragmentation"; Compression and Fragmentation";
} }
} }
<CODE ENDS> <CODE ENDS>
Figure 6 Figure 6: SCHC YANG Data Model
7. Implementation Status
This section records the status of known implementations of the
protocol defined by this specification at the time of posting of this
Internet-Draft, and is based on a proposal described in [RFC7942].
The description of implementations in this section is intended to
assist the IETF in its decision processes in progressing drafts to
RFCs. Please note that the listing of any individual implementation
here does not imply endorsement by the IETF. Furthermore, no effort
has been spent to verify the information presented here that was
supplied by IETF contributors. This is not intended as, and must not
be construed to be, a catalog of available implementations or their
features. Readers are advised to note that other implementations may
exist.
According to [RFC7942], "this will allow reviewers and working groups
to assign due consideration to documents that have the benefit of
running code, which may serve as evidence of valuable experimentation
and feedback that have made the implemented protocols more mature.
It is up to the individual working groups to use this information as
they see fit".
* Openschc is implementing the conversion between the local rule
representation and the representation conforming to the data model
in JSON and CBOR (following -08 draft).
8. IANA Considerations
This document registers one URI and one YANG modules.
8.1. URI Registration
This document requests IANA to register the following URI in the
"IETF XML Registry" [RFC3688]:
URI: urn:ietf:params:xml:ns:yang:ietf-schc
Registrant Contact: The IESG. 7. IANA Considerations
XML: N/A; the requested URI is an XML namespace. This document registers one URI and one YANG data model.
8.2. YANG Module Name Registration 7.1. URI Registration
This document registers the following one YANG modules in the "YANG IANA registered the following URI in the "IETF XML Registry"
Module Names" registry [RFC6020]. [RFC3688]:
name: ietf-schc URI: urn:ietf:params:xml:ns:yang:ietf-schc
Registrant Contact: The IESG.
XML: N/A; the requested URI is an XML namespace.
namespace: urn:ietf:params:xml:ns:yang:ietf-schc 7.2. YANG Module Name Registration
prefix: schc IANA has registered the following YANG data model in the "YANG Module
Names" registry [RFC6020].
reference: RFC XXXX Data Model for Static Context Header name: ietf-schc
Compression (SCHC) namespace: urn:ietf:params:xml:ns:yang:ietf-schc
prefix: schc
reference: RFC 9363
9. Security Considerations 8. Security Considerations
The YANG module specified in this document defines a schema for data The YANG module specified in this document defines a schema for data
that is designed to be accessed via network management protocols such that is designed to be accessed via network management protocols such
as NETCONF [RFC6241] or RESTCONF [RFC8040]. The lowest NETCONF layer as NETCONF [RFC6241] or RESTCONF [RFC8040]. The lowest NETCONF layer
is the secure transport layer, and the mandatory-to-implement secure is the secure transport layer, and the mandatory-to-implement secure
transport is Secure Shell (SSH) [RFC6242]. The lowest RESTCONF layer transport is Secure Shell (SSH) [RFC6242]. The lowest RESTCONF layer
is HTTPS, and the mandatory-to-implement secure transport is TLS is HTTPS, and the mandatory-to-implement secure transport is TLS
[RFC8446]. [RFC8446].
The Network Configuration Access Control Model (NACM) [RFC8341] The Network Configuration Access Control Model (NACM) [RFC8341]
provides the means to restrict access for particular NETCONF or provides the means to restrict access for particular NETCONF or
RESTCONF users to a preconfigured subset of all available NETCONF or RESTCONF users to a preconfigured subset of all available NETCONF or
RESTCONF protocol operations and content. RESTCONF protocol operations and content.
This data model formalizes the rules elements described in [RFC8724] There are a number of data nodes defined in this YANG module that are
for compression, and fragmentation. As explained in the architecture writable/creatable/deletable (i.e., config true, which is the
document [I-D.ietf-lpwan-architecture], a rule can be read, created, default). These data nodes may be considered sensitive or vulnerable
updated or deleted in response to a management request. These in some network environments. Write operations (e.g., edit-config)
actions can be done between two instances of SCHC or between a SCHC to these data nodes without proper protection can have a negative
instance and a rule repository. effect on network operations. These are the subtrees and data nodes
and their sensitivity/vulnerability:
create
(-------) read +=======+ *
( rules )<------->|Rule |<--|-------->
(-------) update |Manager| NETCONF, RESTCONF,...
. read delete +=======+ request
.
+-------+
<===| R & D |<===
===>| C & F |===>
+-------+
The rule contains sensitive information such as the application IPv6
address where the device's data will be sent after decompression. A
device may try to modify other devices' rules by changing the
application address and may block communication or allows traffic
eavesdropping. Therefore, a device must be allowed to modify only
its own rules on the remote SCHC instance. The identity of the
requester must be validated. This can be done through certificates
or access lists. By reading a module, an attacker may know the
traffic a device can generate and learn about application addresses
or REST API.
The full tree is sensitive, since it represents all the elements that
can be managed. This module aims to be encapsulated into a YANG
module including access controls and identities.
10. Annex A : Example
The informal rules given Figure 7 will represented in XML as shown in
Figure 8.
/-------------------------\
|Rule 6/3 110 |
|---------------+---+--+--+----------------+-------+----------------\
|IPV6.VER | 4| 1|BI| 6|EQUAL |NOT-SENT |
|IPV6.TC | 8| 1|BI| 0|EQUAL |NOT-SENT |
|IPV6.FL | 20| 1|BI| 0|IGNORE |NOT-SENT |
|IPV6.LEN | 16| 1|BI| |IGNORE |COMPUTE-LENGTH |
|IPV6.NXT | 8| 1|BI| 58|EQUAL |NOT-SENT |
|IPV6.HOP_LMT | 8| 1|BI| 255|IGNORE |NOT-SENT |
|IPV6.DEV_PREFIX| 64| 1|BI|200104701f2101d2|EQUAL |NOT-SENT |
|IPV6.DEV_IID | 64| 1|BI|0000000000000003|EQUAL |NOT-SENT |
|IPV6.APP_PREFIX| 64| 1|BI| |IGNORE |VALUE-SENT |
|IPV6.APP_IID | 64| 1|BI| |IGNORE |VALUE-SENT |
\---------------+---+--+--+----------------+-------+----------------/
/-------------------------\
|Rule 12/11 00001100 |
!=========================+=========================================\
!^ Fragmentation mode : NoAck header dtag 2 Window 0 FCN 3 UP ^!
!^ No Tile size specified ^!
!^ RCS Algorithm: RCS_CRC32 ^!
\===================================================================/
/-------------------------\
|Rule 100/8 01100100 |
| NO COMPRESSION RULE |
\-------------------------/
Figure 7: Rules example
<?xml version='1.0' encoding='UTF-8'?>
<schc xmlns="urn:ietf:params:xml:ns:yang:ietf-schc">
<rule>
<rule-id-value>6</rule-id-value>
<rule-id-length>3</rule-id-length>
<rule-nature>nature-compression</rule-nature>
<entry>
<field-id>fid-ipv6-version</field-id>
<field-length>4</field-length>
<field-position>1</field-position>
<direction-indicator>di-bidirectional</direction-indicator>
<matching-operator>mo-equal</matching-operator>
<comp-decomp-action>cda-not-sent</comp-decomp-action>
<target-value>
<index>0</index>
<value>AAY=</value>
</target-value>
</entry>
<entry>
<field-id>fid-ipv6-trafficclass</field-id>
<field-length>8</field-length>
<field-position>1</field-position>
<direction-indicator>di-bidirectional</direction-indicator>
<matching-operator>mo-equal</matching-operator>
<comp-decomp-action>cda-not-sent</comp-decomp-action>
<target-value>
<index>0</index>
<value>AA==</value>
</target-value>
</entry>
<entry>
<field-id>fid-ipv6-flowlabel</field-id>
<field-length>20</field-length>
<field-position>1</field-position>
<direction-indicator>di-bidirectional</direction-indicator>
<matching-operator>mo-ignore</matching-operator>
<comp-decomp-action>cda-not-sent</comp-decomp-action>
<target-value>
<index>0</index>
<value>AA==</value>
</target-value>
</entry>
<entry>
<field-id>fid-ipv6-payload-length</field-id>
<field-length>16</field-length>
<field-position>1</field-position>
<direction-indicator>di-bidirectional</direction-indicator>
<matching-operator>mo-ignore</matching-operator>
<comp-decomp-action>cda-compute</comp-decomp-action>
</entry>
<entry>
<field-id>fid-ipv6-nextheader</field-id>
<field-length>8</field-length>
<field-position>1</field-position>
<direction-indicator>di-bidirectional</direction-indicator>
<matching-operator>mo-equal</matching-operator>
<comp-decomp-action>cda-not-sent</comp-decomp-action>
<target-value>
<index>0</index>
<value>ADo=</value>
</target-value>
</entry>
<entry>
<field-id>fid-ipv6-hoplimit</field-id>
<field-length>8</field-length>
<field-position>1</field-position>
<direction-indicator>di-bidirectional</direction-indicator>
<matching-operator>mo-ignore</matching-operator>
<comp-decomp-action>cda-not-sent</comp-decomp-action>
<target-value>
<index>0</index>
<value>AP8=</value>
</target-value>
</entry>
<entry>
<field-id>fid-ipv6-devprefix</field-id>
<field-length>64</field-length>
<field-position>1</field-position>
<direction-indicator>di-bidirectional</direction-indicator>
<matching-operator>mo-equal</matching-operator>
<comp-decomp-action>cda-not-sent</comp-decomp-action>
<target-value>
<index>0</index>
<value>IAEEcB8hAdI=</value>
</target-value>
</entry>
<entry>
<field-id>fid-ipv6-deviid</field-id>
<field-length>64</field-length>
<field-position>1</field-position>
<direction-indicator>di-bidirectional</direction-indicator>
<matching-operator>mo-equal</matching-operator>
<comp-decomp-action>cda-not-sent</comp-decomp-action>
<target-value>
<index>0</index>
<value>AAAAAAAAAAM=</value>
</target-value>
</entry>
<entry>
<field-id>fid-ipv6-appprefix</field-id>
<field-length>64</field-length>
<field-position>1</field-position>
<direction-indicator>di-bidirectional</direction-indicator>
<matching-operator>mo-ignore</matching-operator>
<comp-decomp-action>cda-value-sent</comp-decomp-action>
</entry>
<entry>
<field-id>fid-ipv6-appiid</field-id>
<field-length>64</field-length>
<field-position>1</field-position>
<direction-indicator>di-bidirectional</direction-indicator>
<matching-operator>mo-ignore</matching-operator>
<comp-decomp-action>cda-value-sent</comp-decomp-action>
</entry>
</rule>
<rule>
<rule-id-value>12</rule-id-value>
<rule-id-length>11</rule-id-length>
<rule-nature>nature-fragmentation</rule-nature>
<direction>di-up</direction>
<rcs-algorithm>rcs-crc32</rcs-algorithm>
<dtag-size>2</dtag-size>
<fcn-size>3</fcn-size>
<fragmentation-mode>fragmentation-mode-no-ack</fragmentation-mode>
</rule>
<rule>
<rule-id-value>100</rule-id-value>
<rule-id-length>8</rule-id-length>
<rule-nature>nature-no-compression</rule-nature>
</rule>
</schc>
Figure 8: XML representation of the rules. /schc: All the data nodes may be modified. The Rule contains
sensitive information, such as the application IPv6 address where
the device's data will be sent after decompression. An attacker
may try to modify other devices' Rules by changing the application
address and may block communication or allows traffic
eavesdropping. Therefore, a device must be allowed to modify only
its own rules on the remote SCHC instance. The identity of the
requester must be validated. This can be done through
certificates or access lists. Modification may be allowed
regarding the Field Descriptor (i.e., IPv6 addresses field
descriptors should not be modified, but UDP dev port could be
changed).
11. Acknowledgements Some of the readable data nodes in this YANG module may be considered
sensitive or vulnerable in some network environments. It is thus
important to control read access (e.g., via get, get-config, or
notification) to these data nodes. These are the subtrees and data
nodes and their sensitivity/vulnerability:
The authors would like to thank Dominique Barthel, Carsten Bormann, /schc: By reading a module, an attacker may learn the traffic
Ivan Martinez, Alexander Pelov for their careful reading and valuable generated by a device and can also learn about application
inputs. A special thanks for Joe Clarke, Carl Moberg, Tom Petch, addresses or REST API.
Martin Thomson, and Eric Vyncke for their explanations and wise
advices when building the model.
12. References 9. References
12.1. Normative References 9.1. Normative References
[RFC0768] Postel, J., "User Datagram Protocol", STD 6, RFC 768, [RFC0768] Postel, J., "User Datagram Protocol", STD 6, RFC 768,
DOI 10.17487/RFC0768, August 1980, DOI 10.17487/RFC0768, August 1980,
<https://www.rfc-editor.org/info/rfc768>. <https://www.rfc-editor.org/info/rfc768>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>. <https://www.rfc-editor.org/info/rfc2119>.
skipping to change at page 53, line 26 skipping to change at line 2259
Compression and Fragmentation", RFC 8724, Compression and Fragmentation", RFC 8724,
DOI 10.17487/RFC8724, April 2020, DOI 10.17487/RFC8724, April 2020,
<https://www.rfc-editor.org/info/rfc8724>. <https://www.rfc-editor.org/info/rfc8724>.
[RFC8824] Minaburo, A., Toutain, L., and R. Andreasen, "Static [RFC8824] Minaburo, A., Toutain, L., and R. Andreasen, "Static
Context Header Compression (SCHC) for the Constrained Context Header Compression (SCHC) for the Constrained
Application Protocol (CoAP)", RFC 8824, Application Protocol (CoAP)", RFC 8824,
DOI 10.17487/RFC8824, June 2021, DOI 10.17487/RFC8824, June 2021,
<https://www.rfc-editor.org/info/rfc8824>. <https://www.rfc-editor.org/info/rfc8824>.
12.2. Informative References 9.2. Informative References
[I-D.ietf-lpwan-architecture] [LPWAN-ARCH]
Pelov, A., Thubert, P., and A. Minaburo, "LPWAN Static Pelov, A., Thubert, P., and A. Minaburo, "LPWAN Static
Context Header Compression (SCHC) Architecture", Work in Context Header Compression (SCHC) Architecture", Work in
Progress, Internet-Draft, draft-ietf-lpwan-architecture- Progress, Internet-Draft, draft-ietf-lpwan-architecture-
02, 30 June 2022, <https://www.ietf.org/archive/id/draft- 02, 30 June 2022, <https://datatracker.ietf.org/doc/html/
ietf-lpwan-architecture-02.txt>. draft-ietf-lpwan-architecture-02>.
[RFC7942] Sheffer, Y. and A. Farrel, "Improving Awareness of Running
Code: The Implementation Status Section", BCP 205,
RFC 7942, DOI 10.17487/RFC7942, July 2016,
<https://www.rfc-editor.org/info/rfc7942>.
[RFC7950] Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language", [RFC7950] Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language",
RFC 7950, DOI 10.17487/RFC7950, August 2016, RFC 7950, DOI 10.17487/RFC7950, August 2016,
<https://www.rfc-editor.org/info/rfc7950>. <https://www.rfc-editor.org/info/rfc7950>.
[RFC7967] Bhattacharyya, A., Bandyopadhyay, S., Pal, A., and T. [RFC7967] Bhattacharyya, A., Bandyopadhyay, S., Pal, A., and T.
Bose, "Constrained Application Protocol (CoAP) Option for Bose, "Constrained Application Protocol (CoAP) Option for
No Server Response", RFC 7967, DOI 10.17487/RFC7967, No Server Response", RFC 7967, DOI 10.17487/RFC7967,
August 2016, <https://www.rfc-editor.org/info/rfc7967>. August 2016, <https://www.rfc-editor.org/info/rfc7967>.
[RFC8376] Farrell, S., Ed., "Low-Power Wide Area Network (LPWAN) [RFC8376] Farrell, S., Ed., "Low-Power Wide Area Network (LPWAN)
Overview", RFC 8376, DOI 10.17487/RFC8376, May 2018, Overview", RFC 8376, DOI 10.17487/RFC8376, May 2018,
<https://www.rfc-editor.org/info/rfc8376>. <https://www.rfc-editor.org/info/rfc8376>.
[RFC9011] Gimenez, O., Ed. and I. Petrov, Ed., "Static Context [RFC9011] Gimenez, O., Ed. and I. Petrov, Ed., "Static Context
Header Compression and Fragmentation (SCHC) over LoRaWAN", Header Compression and Fragmentation (SCHC) over LoRaWAN",
RFC 9011, DOI 10.17487/RFC9011, April 2021, RFC 9011, DOI 10.17487/RFC9011, April 2021,
<https://www.rfc-editor.org/info/rfc9011>. <https://www.rfc-editor.org/info/rfc9011>.
Appendix A. Example
The informal Rules given Figure 7 are represented in XML, as shown in
Figure 8.
/-------------------------\
|Rule 6/3 110 |
|---------------+---+--+--+----------------+-------+----------------\
|IPV6.VER | 4| 1|BI| 6|EQUAL |NOT-SENT |
|IPV6.TC | 8| 1|BI| 0|EQUAL |NOT-SENT |
|IPV6.FL | 20| 1|BI| 0|IGNORE |NOT-SENT |
|IPV6.LEN | 16| 1|BI| |IGNORE |COMPUTE-LENGTH |
|IPV6.NXT | 8| 1|BI| 58|EQUAL |NOT-SENT |
|IPV6.HOP_LMT | 8| 1|BI| 255|IGNORE |NOT-SENT |
|IPV6.DEV_PREFIX| 64| 1|BI|200104701f2101d2|EQUAL |NOT-SENT |
|IPV6.DEV_IID | 64| 1|BI|0000000000000003|EQUAL |NOT-SENT |
|IPV6.APP_PREFIX| 64| 1|BI| |IGNORE |VALUE-SENT |
|IPV6.APP_IID | 64| 1|BI| |IGNORE |VALUE-SENT |
\---------------+---+--+--+----------------+-------+----------------/
/-------------------------\
|Rule 12/11 00001100 |
!=========================+=========================================\
!^ Fragmentation mode : NoAck header dtag 2 Window 0 FCN 3 UP ^!
!^ No Tile size specified ^!
!^ RCS Algorithm: RCS_CRC32 ^!
\===================================================================/
/-------------------------\
|Rule 100/8 01100100 |
| NO-COMPRESSION RULE |
\-------------------------/
Figure 7: Rules Example
<?xml version='1.0' encoding='UTF-8'?>
<schc xmlns="urn:ietf:params:xml:ns:yang:ietf-schc">
<rule>
<rule-id-value>6</rule-id-value>
<rule-id-length>3</rule-id-length>
<rule-nature>nature-compression</rule-nature>
<entry>
<field-id>fid-ipv6-version</field-id>
<field-length>4</field-length>
<field-position>1</field-position>
<direction-indicator>di-bidirectional</direction-indicator>
<matching-operator>mo-equal</matching-operator>
<comp-decomp-action>cda-not-sent</comp-decomp-action>
<target-value>
<index>0</index>
<value>AAY=</value>
</target-value>
</entry>
<entry>
<field-id>fid-ipv6-trafficclass</field-id>
<field-length>8</field-length>
<field-position>1</field-position>
<direction-indicator>di-bidirectional</direction-indicator>
<matching-operator>mo-equal</matching-operator>
<comp-decomp-action>cda-not-sent</comp-decomp-action>
<target-value>
<index>0</index>
<value>AA==</value>
</target-value>
</entry>
<entry>
<field-id>fid-ipv6-flowlabel</field-id>
<field-length>20</field-length>
<field-position>1</field-position>
<direction-indicator>di-bidirectional</direction-indicator>
<matching-operator>mo-ignore</matching-operator>
<comp-decomp-action>cda-not-sent</comp-decomp-action>
<target-value>
<index>0</index>
<value>AA==</value>
</target-value>
</entry>
<entry>
<field-id>fid-ipv6-payload-length</field-id>
<field-length>16</field-length>
<field-position>1</field-position>
<direction-indicator>di-bidirectional</direction-indicator>
<matching-operator>mo-ignore</matching-operator>
<comp-decomp-action>cda-compute</comp-decomp-action>
</entry>
<entry>
<field-id>fid-ipv6-nextheader</field-id>
<field-length>8</field-length>
<field-position>1</field-position>
<direction-indicator>di-bidirectional</direction-indicator>
<matching-operator>mo-equal</matching-operator>
<comp-decomp-action>cda-not-sent</comp-decomp-action>
<target-value>
<index>0</index>
<value>ADo=</value>
</target-value>
</entry>
<entry>
<field-id>fid-ipv6-hoplimit</field-id>
<field-length>8</field-length>
<field-position>1</field-position>
<direction-indicator>di-bidirectional</direction-indicator>
<matching-operator>mo-ignore</matching-operator>
<comp-decomp-action>cda-not-sent</comp-decomp-action>
<target-value>
<index>0</index>
<value>AP8=</value>
</target-value>
</entry>
<entry>
<field-id>fid-ipv6-devprefix</field-id>
<field-length>64</field-length>
<field-position>1</field-position>
<direction-indicator>di-bidirectional</direction-indicator>
<matching-operator>mo-equal</matching-operator>
<comp-decomp-action>cda-not-sent</comp-decomp-action>
<target-value>
<index>0</index>
<value>IAEEcB8hAdI=</value>
</target-value>
</entry>
<entry>
<field-id>fid-ipv6-deviid</field-id>
<field-length>64</field-length>
<field-position>1</field-position>
<direction-indicator>di-bidirectional</direction-indicator>
<matching-operator>mo-equal</matching-operator>
<comp-decomp-action>cda-not-sent</comp-decomp-action>
<target-value>
<index>0</index>
<value>AAAAAAAAAAM=</value>
</target-value>
</entry>
<entry>
<field-id>fid-ipv6-appprefix</field-id>
<field-length>64</field-length>
<field-position>1</field-position>
<direction-indicator>di-bidirectional</direction-indicator>
<matching-operator>mo-ignore</matching-operator>
<comp-decomp-action>cda-value-sent</comp-decomp-action>
</entry>
<entry>
<field-id>fid-ipv6-appiid</field-id>
<field-length>64</field-length>
<field-position>1</field-position>
<direction-indicator>di-bidirectional</direction-indicator>
<matching-operator>mo-ignore</matching-operator>
<comp-decomp-action>cda-value-sent</comp-decomp-action>
</entry>
</rule>
<rule>
<rule-id-value>12</rule-id-value>
<rule-id-length>11</rule-id-length>
<rule-nature>nature-fragmentation</rule-nature>
<direction>di-up</direction>
<rcs-algorithm>rcs-crc32</rcs-algorithm>
<dtag-size>2</dtag-size>
<fcn-size>3</fcn-size>
<fragmentation-mode>
fragmentation-mode-no-ack
</fragmentation-mode>
</rule>
<rule>
<rule-id-value>100</rule-id-value>
<rule-id-length>8</rule-id-length>
<rule-nature>nature-no-compression</rule-nature>
</rule>
</schc>
Figure 8: XML Representation of the Rules
Acknowledgments
The authors would like to thank Dominique Barthel, Carsten Bormann,
Ivan Martinez, and Alexander Pelov for their careful reading and
valuable inputs. A special thanks for Joe Clarke, Carl Moberg, Tom
Petch, Martin Thomson, and Éric Vyncke for their explanations and
wise advice when building the model.
Authors' Addresses Authors' Addresses
Ana Minaburo Ana Minaburo
Acklio Acklio
1137A avenue des Champs Blancs 1137A avenue des Champs Blancs
35510 Cesson-Sevigne Cedex 35510 Cesson-Sevigne Cedex
France France
Email: ana@ackl.io Email: ana@ackl.io
Laurent Toutain Laurent Toutain
Institut MINES TELECOM; IMT Atlantique Institut MINES TELECOM; IMT Atlantique
2 rue de la Chataigneraie 2 rue de la Chataigneraie CS 17607
CS 17607
35576 Cesson-Sevigne Cedex 35576 Cesson-Sevigne Cedex
France France
Email: Laurent.Toutain@imt-atlantique.fr Email: Laurent.Toutain@imt-atlantique.fr
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