<?xmlversion="1.0" encoding="US-ASCII"?> <!-- [rfced] updated by Chris /07/23/19 --> <?rfc toc="yes"?> <?rfc tocompact="yes"?> <?rfc tocdepth="3"?> <?rfc tocindent="yes"?> <?rfc symrefs="yes"?> <?rfc sortrefs="yes"?> <?rfc comments="yes"?> <?rfc inline="yes"?> <?rfc compact="yes"?> <?rfc subcompact="no"?> <!DOCTYPE rfc SYSTEM "rfc2629.dtd">version='1.0' encoding='utf-8'?> <rfcsubmissionType="IETF"xmlns:xi="http://www.w3.org/2001/XInclude" version="3" category="std"consensus="yes" number="XXXX" ipr="trust200902">consensus="true" docName="draft-ietf-mpls-sr-over-ip-07" indexInclude="true" ipr="trust200902" number="8663" prepTime="2019-12-04T21:02:22" scripts="Common,Latin" sortRefs="true" submissionType="IETF" symRefs="true" tocDepth="3" tocInclude="true" xml:lang="en"> <link href="https://datatracker.ietf.org/doc/draft-ietf-mpls-sr-over-ip-07" rel="prev"/> <link href="https://dx.doi.org/10.17487/rfc8663" rel="alternate"/> <link href="urn:issn:2070-1721" rel="alternate"/> <front> <titleabbrev="SR-MPLS over IP">SR-MPLSabbrev="SR-MPLS-over-IP">MPLS Segment Routing over IP</title> <seriesInfo name="RFC" value="8663" stream="IETF"/> <author fullname="Xiaohu Xu" initials="X." surname="Xu"><organization>Alibaba,<organization showOnFrontPage="true">Alibaba, Inc</organization> <address> <email>xiaohu.xxh@alibaba-inc.com</email> </address> </author> <author fullname="Stewart Bryant" initials="S."surname="Bryant "> <organization>Huawei</organization>surname="Bryant"> <organization showOnFrontPage="true">Futurewei Technologies</organization> <address> <email>stewart.bryant@gmail.com</email> </address> </author> <author fullname="Adrian Farrel" initials="A."surname="Farrel "> <organization>Oldsurname="Farrel"> <organization showOnFrontPage="true">Old Dog Consulting</organization> <address> <email>adrian@olddog.co.uk</email> </address> </author> <author fullname="Syed Hassan" initials="S." surname="Hassan"><organization>Cisco</organization><organization showOnFrontPage="true">Cisco</organization> <address> <email>shassan@cisco.com</email> </address> </author> <author fullname="Wim Henderickx" initials="W" surname="Henderickx"><organization>Nokia</organization><organization showOnFrontPage="true">Nokia</organization> <address> <email>wim.henderickx@nokia.com</email> </address> </author> <author fullname="Zhenbin Li" initials="Z." surname="Li"><organization>Huawei</organization><organization showOnFrontPage="true">Huawei</organization> <address> <email>lizhenbin@huawei.com</email> </address> </author> <dateyear="2019" month="July"/> <!-- [rfced] Please insert any keywords (beyond those that appear in the title) for use on https://www.rfc-editor.org/search. --> <keyword>example</keyword> <abstract> <t>MPLSmonth="12" year="2019"/> <keyword>MPLS-SR-over-IP, SR-MPLS-over-IP, MPLS-SR-over-UDP, SR-MPLS-over-UDP</keyword> <abstract pn="section-abstract"> <t pn="section-abstract-1">MPLS Segment Routing (SR-MPLS) isan MPLS data plane-baseda method of source routingparadigm in which the sender ofa packetis allowed to partially or completely specify the route the packet takesthroughthe networkan MPLS data plane by imposingstackeda stack of MPLS labels on thepacket.packet to specify the path together with any packet-specific instructions to be executed on it. SR-MPLS can be leveraged to realize asource routingsource-routing mechanism across MPLS, IPv4, and IPv6 data planes by using an MPLS label stack as asource routingsource-routing instruction set while making no changes to SR-MPLS specifications and interworking with SR-MPLS implementations.</t><t>This<t pn="section-abstract-2">This document describes howSR-MPLS capableSR-MPLS-capable routers and IP-only routers can seamlesslyco-existcoexist and interoperate through the use of SR-MPLS label stacks and IP encapsulation/tunneling such asMPLS-in-UDPMPLS-over-UDP as defined in RFC 7510.</t> </abstract> <boilerplate> <section anchor="status-of-memo" numbered="false" removeInRFC="false" toc="exclude" pn="section-boilerplate.1"> <name slugifiedName="name-status-of-this-memo">Status of This Memo</name> <t pn="section-boilerplate.1-1"> This is an Internet Standards Track document. </t> <t pn="section-boilerplate.1-2"> This document is a product of the Internet Engineering Task Force (IETF). It represents the consensus of the IETF community. It has received public review and has been approved for publication by the Internet Engineering Steering Group (IESG). Further information on Internet Standards is available in Section 2 of RFC 7841. </t> <t pn="section-boilerplate.1-3"> Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at <eref target="https://www.rfc-editor.org/info/rfc8663" brackets="none"/>. </t> </section> <section anchor="copyright" numbered="false" removeInRFC="false" toc="exclude" pn="section-boilerplate.2"> <name slugifiedName="name-copyright-notice">Copyright Notice</name> <t pn="section-boilerplate.2-1"> Copyright (c) 2019 IETF Trust and the persons identified as the document authors. All rights reserved. </t> <t pn="section-boilerplate.2-2"> This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (<eref target="https://trustee.ietf.org/license-info" brackets="none"/>) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. </t> </section> </boilerplate> <toc> <section anchor="toc" numbered="false" removeInRFC="false" toc="exclude" pn="section-toc.1"> <name slugifiedName="name-table-of-contents">Table of Contents</name> <ul bare="true" empty="true" indent="2" spacing="compact" pn="section-toc.1-1"> <li pn="section-toc.1-1.1"> <t keepWithNext="true" pn="section-toc.1-1.1.1"><xref derivedContent="1" format="counter" sectionFormat="of" target="section-1"/>. <xref derivedContent="" format="title" sectionFormat="of" target="name-introduction">Introduction</xref></t> <ul bare="true" empty="true" indent="2" spacing="compact" pn="section-toc.1-1.1.2"> <li pn="section-toc.1-1.1.2.1"> <t keepWithNext="true" pn="section-toc.1-1.1.2.1.1"><xref derivedContent="1.1" format="counter" sectionFormat="of" target="section-1.1"/>. <xref derivedContent="" format="title" sectionFormat="of" target="name-terminology">Terminology</xref></t> </li> </ul> </li> <li pn="section-toc.1-1.2"> <t keepWithNext="true" pn="section-toc.1-1.2.1"><xref derivedContent="2" format="counter" sectionFormat="of" target="section-2"/>. <xref derivedContent="" format="title" sectionFormat="of" target="name-use-cases">Use Cases</xref></t> </li> <li pn="section-toc.1-1.3"> <t keepWithNext="true" pn="section-toc.1-1.3.1"><xref derivedContent="3" format="counter" sectionFormat="of" target="section-3"/>. <xref derivedContent="" format="title" sectionFormat="of" target="name-procedures-of-sr-mpls-over-">Procedures of SR-MPLS-over-IP</xref></t> <ul bare="true" empty="true" indent="2" spacing="compact" pn="section-toc.1-1.3.2"> <li pn="section-toc.1-1.3.2.1"> <t keepWithNext="true" pn="section-toc.1-1.3.2.1.1"><xref derivedContent="3.1" format="counter" sectionFormat="of" target="section-3.1"/>. <xref derivedContent="" format="title" sectionFormat="of" target="name-forwarding-entry-constructi">Forwarding Entry Construction</xref></t> <ul bare="true" empty="true" indent="2" spacing="compact" pn="section-toc.1-1.3.2.1.2"> <li pn="section-toc.1-1.3.2.1.2.1"> <t keepWithNext="true" pn="section-toc.1-1.3.2.1.2.1.1"><xref derivedContent="3.1.1" format="counter" sectionFormat="of" target="section-3.1.1"/>. <xref derivedContent="" format="title" sectionFormat="of" target="name-fib-construction-example">FIB Construction Example</xref></t> </li> </ul> </li> <li pn="section-toc.1-1.3.2.2"> <t keepWithNext="true" pn="section-toc.1-1.3.2.2.1"><xref derivedContent="3.2" format="counter" sectionFormat="of" target="section-3.2"/>. <xref derivedContent="" format="title" sectionFormat="of" target="name-packet-forwarding-procedure">Packet-Forwarding Procedures</xref></t> <ul bare="true" empty="true" indent="2" spacing="compact" pn="section-toc.1-1.3.2.2.2"> <li pn="section-toc.1-1.3.2.2.2.1"> <t keepWithNext="true" pn="section-toc.1-1.3.2.2.2.1.1"><xref derivedContent="3.2.1" format="counter" sectionFormat="of" target="section-3.2.1"/>. <xref derivedContent="" format="title" sectionFormat="of" target="name-packet-forwarding-with-penu">Packet Forwarding with Penultimate Hop Popping</xref></t> </li> <li pn="section-toc.1-1.3.2.2.2.2"> <t keepWithNext="true" pn="section-toc.1-1.3.2.2.2.2.1"><xref derivedContent="3.2.2" format="counter" sectionFormat="of" target="section-3.2.2"/>. <xref derivedContent="" format="title" sectionFormat="of" target="name-packet-forwarding-without-p">Packet Forwarding without Penultimate Hop Popping</xref></t> </li> <li pn="section-toc.1-1.3.2.2.2.3"> <t keepWithNext="true" pn="section-toc.1-1.3.2.2.2.3.1"><xref derivedContent="3.2.3" format="counter" sectionFormat="of" target="section-3.2.3"/>. <xref derivedContent="" format="title" sectionFormat="of" target="name-additional-forwarding-proce">Additional Forwarding Procedures</xref></t> </li> </ul> </li> </ul> </li> <li pn="section-toc.1-1.4"> <t keepWithNext="true" pn="section-toc.1-1.4.1"><xref derivedContent="4" format="counter" sectionFormat="of" target="section-4"/>. <xref derivedContent="" format="title" sectionFormat="of" target="name-iana-considerations">IANA Considerations</xref></t> </li> <li pn="section-toc.1-1.5"> <t keepWithNext="true" pn="section-toc.1-1.5.1"><xref derivedContent="5" format="counter" sectionFormat="of" target="section-5"/>. <xref derivedContent="" format="title" sectionFormat="of" target="name-security-considerations">Security Considerations</xref></t> </li> <li pn="section-toc.1-1.6"> <t keepWithNext="true" pn="section-toc.1-1.6.1"><xref derivedContent="6" format="counter" sectionFormat="of" target="section-6"/>. <xref derivedContent="" format="title" sectionFormat="of" target="name-references">References</xref></t> <ul bare="true" empty="true" indent="2" spacing="compact" pn="section-toc.1-1.6.2"> <li pn="section-toc.1-1.6.2.1"> <t keepWithNext="true" pn="section-toc.1-1.6.2.1.1"><xref derivedContent="6.1" format="counter" sectionFormat="of" target="section-6.1"/>. <xref derivedContent="" format="title" sectionFormat="of" target="name-normative-references">Normative References</xref></t> </li> <li pn="section-toc.1-1.6.2.2"> <t keepWithNext="true" pn="section-toc.1-1.6.2.2.1"><xref derivedContent="6.2" format="counter" sectionFormat="of" target="section-6.2"/>. <xref derivedContent="" format="title" sectionFormat="of" target="name-informative-references">Informative References</xref></t> </li> </ul> </li> <li pn="section-toc.1-1.7"> <t keepWithNext="true" pn="section-toc.1-1.7.1"><xref derivedContent="" format="none" sectionFormat="of" target="section-appendix.a"/><xref derivedContent="" format="title" sectionFormat="of" target="name-acknowledgements">Acknowledgements</xref></t> </li> <li pn="section-toc.1-1.8"> <t keepWithNext="true" pn="section-toc.1-1.8.1"><xref derivedContent="" format="none" sectionFormat="of" target="section-appendix.b"/><xref derivedContent="" format="title" sectionFormat="of" target="name-contributors">Contributors</xref></t> </li> <li pn="section-toc.1-1.9"> <t keepWithNext="true" pn="section-toc.1-1.9.1"><xref derivedContent="" format="none" sectionFormat="of" target="section-appendix.c"/><xref derivedContent="" format="title" sectionFormat="of" target="name-authors-addresses">Authors' Addresses</xref></t> </li> </ul> </section> </toc> </front> <middle> <sectiontitle="Introduction"> <t>MPLSnumbered="true" toc="include" removeInRFC="false" pn="section-1"> <name slugifiedName="name-introduction">Introduction</name> <t pn="section-1-1">MPLS Segment Routing (SR-MPLS) <xreftarget="RFCYYYY"/>target="RFC8660" format="default" sectionFormat="of" derivedContent="RFC8660"/> is a method of source routing a packet through an MPLS dataplane-based source routing paradigm in whichplane. This is achieved by the senderofimposing apacket is allowed tostack of MPLS labels that partially or completely specify theroutepath that the packettakes through the network by imposing stacked MPLS labelsis to take and any instructions to be executed on thepacket.packet as it passes through the network. SR-MPLS uses an MPLS label stack to encode asource routing instruction set.sequence of source-routing instructions. This can be used to realize asource routingsource-routing mechanism that can operate across MPLS, IPv4, and IPv6 data planes. This approach makes no changes to SR-MPLS specifications and allows interworking with SR-MPLS implementations. More specifically, thesource routing instruction set information containedsource-routing instructions in asource routedsource-routed packet could be uniformly encoded as an MPLS label stackno matterregardless of whether the underlay is IPv4, IPv6 (including Segment Routing for IPv6 (SRv6)[RFC8354]),<xref target="RFC8354" format="default" sectionFormat="of" derivedContent="RFC8354"/>), or MPLS.</t><t>This<t pn="section-1-2">This document describes howSR-MPLS capableSR-MPLS-capable routers and IP-only routers can seamlesslyco-existcoexist and interoperate through the use of SR-MPLS label stacks and IP encapsulation/tunneling such asMPLS-in-UDPMPLS-over-UDP <xreftarget="RFC7510"/>.</t> <t><xref target="usecases"/>target="RFC7510" format="default" sectionFormat="of" derivedContent="RFC7510"/>.</t> <t pn="section-1-3"><xref target="usecases" format="default" sectionFormat="of" derivedContent="Section 2"/> describes various use cases forthetunneling SR-MPLS over IP. <xreftarget="procs"/>target="procs" format="default" sectionFormat="of" derivedContent="Section 3"/> describes a typical application scenario and how the packet forwarding happens.</t> <section anchor="Abbreviations_Terminology"title="Terminology"> <t>Thisnumbered="true" toc="include" removeInRFC="false" pn="section-1.1"> <name slugifiedName="name-terminology">Terminology</name> <t pn="section-1.1-1">This memo makes use of the terms defined in <xreftarget="RFC3031"/>target="RFC3031" format="default" sectionFormat="of" derivedContent="RFC3031"/> and <xreftarget="RFCYYYY"/>.</t> <t>Thetarget="RFC8660" format="default" sectionFormat="of" derivedContent="RFC8660"/>.</t> <t pn="section-1.1-2"> The key words"MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY","<bcp14>MUST</bcp14>", "<bcp14>MUST NOT</bcp14>", "<bcp14>REQUIRED</bcp14>", "<bcp14>SHALL</bcp14>", "<bcp14>SHALL NOT</bcp14>", "<bcp14>SHOULD</bcp14>", "<bcp14>SHOULD NOT</bcp14>", "<bcp14>RECOMMENDED</bcp14>", "<bcp14>NOT RECOMMENDED</bcp14>", "<bcp14>MAY</bcp14>", and"OPTIONAL""<bcp14>OPTIONAL</bcp14>" in this document are to be interpreted as described inBCP 14BCP 14 <xreftarget="RFC2119"/> <xref target="RFC8174"/>target="RFC2119" format="default" sectionFormat="of" derivedContent="RFC2119"/> <xref target="RFC8174" format="default" sectionFormat="of" derivedContent="RFC8174"/> when, and only when, they appear in all capitals, as shownhere.</t>here. </t> </section> </section> <section anchor="usecases"title="Use Cases"> <t>Tunnelingnumbered="true" toc="include" removeInRFC="false" pn="section-2"> <name slugifiedName="name-use-cases">Use Cases</name> <t pn="section-2-1">Tunneling SR-MPLS using IPv4 and/or IPv6 (including SRv6) tunnels is useful at least in the use cases listed below. In all cases, this can be enabled using an IP tunneling mechanism such asMPLS-in-UDPMPLS-over-UDP as described in <xreftarget="RFC7510"/>.target="RFC7510" format="default" sectionFormat="of" derivedContent="RFC7510"/>. The tunnel selectedMUST<bcp14>MUST</bcp14> have its remoteend pointendpoint (destination) address equal to the address of the nextSR-MPLS capablenode capable of SR-MPLS identified as being on the SR path (i.e., the egress of the active segment). The localend pointendpoint (source) address is set to an address of the encapsulating node. <xreftarget="RFC7510"/>target="RFC7510" format="default" sectionFormat="of" derivedContent="RFC7510"/> gives further advice on how to set the source address if the UDP zero-checksum mode is used withMPLS-in-UDP.MPLS-over-UDP. Using UDP as the encapsulation may be particularly beneficial because it is agnostic of the underlying transport.</t><t><list style="symbols"> <t>Incremental<ul spacing="normal" bare="false" empty="false" pn="section-2-2"> <li pn="section-2-2.1"> <t pn="section-2-2.1.1">Incremental deployment of the SR-MPLS technology may be facilitated by tunneling SR-MPLS packets across parts of a network that are not SR-MPLS as shown in <xreftarget="islandsFig"/>.target="islandsFig" format="default" sectionFormat="of" derivedContent="Figure 1"/>. This demonstrates how islands of SR-MPLS may be connected across a legacy network. It may be particularly useful for joining sites (such as data centers). </t> <figure anchor="islandsFig"title="SR-MPLS in UDPalign="left" suppress-title="false" pn="figure-1"> <name slugifiedName="name-sr-mpls-over-udp-to-tunnel-">SR-MPLS-over-UDP to TunnelBetweenbetween SR-MPLSSites"> <artwork><![CDATA[Sites</name> <artwork name="" type="" align="left" alt="" pn="section-2-2.1.2.1"> ________________________ _______ ( ) _______ ( ) ( IP Network ) ( ) ( SR-MPLS ) ( ) ( SR-MPLS ) ( Network ) ( ) ( Network ) ( -------- -------- ) ( | Border | SR-in-UDP Tunnel | Border | ) ( | Router |========================| Router | ) ( | R1 | | R2 | ) ( -------- -------- ) ( ) ( ) ( ) ( ) ( ) ( ) (_______) ( ) (_______) (________________________)]]></artwork> </figure></t> <t>If</artwork> </figure> </li> <li pn="section-2-2.2">If the encoding of entropy(<xref target="RFC6790"/><xref target="RFC6790" format="default" sectionFormat="of" derivedContent="RFC6790"/> is desired,IP tunnelingIP-tunneling mechanisms that allow the encoding of entropy, such asMPLS-in-UDPMPLS-over-UDP encapsulation <xreftarget="RFC7510"/>target="RFC7510" format="default" sectionFormat="of" derivedContent="RFC7510"/> where the source port of the UDP header is used as an entropy field, may be used to maximize the utilization ofECMPEqual-Cost Multipath (ECMP) and/orLAG,Link Aggregation Groups (LAGs), especially when it is difficult to make use of theentropy labelentropy-label mechanism. This is to be contrasted with <xref target="RFC4023"/>format="default" sectionFormat="of" derivedContent="RFC4023"/> whereMPLS-in-IPMPLS-over-IP does not provide for an entropy mechanism. Refer to <xreftarget="ENTROPY-LABEL"/>)target="RFC8662" format="default" sectionFormat="of" derivedContent="RFC8662"/>) for more discussion about using entropy labels inSR-MPLS.</t> <t>TunnelingSR-MPLS.</li> <li pn="section-2-2.3"> <t pn="section-2-2.3.1">Tunneling MPLS over IP provides a technology that enablesSRSegment Routing (SR) in an IPv4 and/or IPv6 network where the routers do not support SRv6 capabilities <xreftarget="IPV6-SEGMENT"/>target="I-D.ietf-6man-segment-routing-header" format="default" sectionFormat="of" derivedContent="IPv6-SRH"/> and where MPLS forwarding is not an option. This is shown in <xreftarget="transitionFig"/>.target="transitionFig" format="default" sectionFormat="of" derivedContent="Figure 2"/>. </t> <figure anchor="transitionFig"title="SR-MPLSalign="left" suppress-title="false" pn="figure-2"> <name slugifiedName="name-sr-mpls-enabled-within-an-i">SR-MPLS EnabledWithinwithin an IPNetwork"> <artwork><![CDATA[Network</name> <artwork name="" type="" align="left" alt="" pn="section-2-2.3.2.1"> __________________________________ __( IP Network )__ __( )__ ( -- -- -- ) -------- -- -- |SR| -- |SR| -- |SR| -- -------- | Ingress| |IR| |IR| | | |IR| | | |IR| | | |IR| |Egress | --->|Egress| -->| Router |===========| |======| |======| |======|Router |--->Router|--> | SR | | | | | | | | | | | | | | | | | | SR | -------- -- -- | | -- | | -- | | -- -------- (__ -- -- -- __) (__ __) (__________________________________) Key: IR : IP-only Router SR : SR-MPLS-capable Router == :SR-MPLS in UDPSR-MPLS-over-UDP Tunnel]]></artwork> </figure></t> </list></t></artwork> </figure> </li> </ul> </section> <section anchor="procs"title="Proceduresnumbered="true" toc="include" removeInRFC="false" pn="section-3"> <name slugifiedName="name-procedures-of-sr-mpls-over-">Procedures ofSR-MPLS over IP"> <t>ThisSR-MPLS-over-IP</name> <t pn="section-3-1">This section describes the construction of forwarding information base (FIB) entries and the forwarding behavior that allow the deployment of SR-MPLS when some routers in the network are IP only (i.e., do not support SR-MPLS). Note that the examples in Sections <xreftarget="fibeg"/>target="fibeg" format="counter" sectionFormat="of" derivedContent="3.1.1"/> and <xreftarget="fwd"/>target="fwd" format="counter" sectionFormat="of" derivedContent="3.2"/> assume that OSPF orISISIS-IS isenabled:enabled; in fact, other mechanisms of discovery and advertisement could be used including other routing protocols (such as BGP) or a central controller.</t> <section anchor="fib"title="Forwardingnumbered="true" toc="include" removeInRFC="false" pn="section-3.1"> <name slugifiedName="name-forwarding-entry-constructi">Forwarding EntryConstruction"> <t>This sub-sectionConstruction</name> <t pn="section-3.1-1">This subsection describesthehow to construct the forwarding information base (FIB) entry on an SR-MPLS-capable router when some or all of thenext-hopsnext hops along the shortest path towards a prefix Segment Identifier(prefix-SID)(Prefix-SID) are IP-only routers. <xref target="fibeg"/>format="default" sectionFormat="of" derivedContent="Section 3.1.1"/> provides a concrete example of how the process applies when using OSPF orISIS.</t> <t>ConsiderIS-IS.</t> <t pn="section-3.1-2">Consider router A that receives a labeled packet with top label L(E) that corresponds to theprefix-SIDPrefix-SID SID(E) of prefix P(E) advertised by router E. Suppose the i-th next-hop router (termed NHi) along the shortest path from router A toward SID(E) is not SR-MPLS capable while both routers A and E are SR-MPLS capable. The following processing steps apply:</t><t> <list style="symbols"> <t>Router<ul spacing="normal" bare="false" empty="false" pn="section-3.1-3"> <li pn="section-3.1-3.1">Router E is SR-MPLS capable, so it advertises a Segment Routing Global Block (SRGB). The SRGB is defined in <xreftarget="RFC8402"/>.target="RFC8402" format="default" sectionFormat="of" derivedContent="RFC8402"/>. There are a number of ways that the advertisement can be achieved including IGPs, BGP, and configuration/management protocols. For example, see <xreftarget="DATACENTER-GATEWAY" />.</t> <t>Whentarget="I-D.ietf-bess-datacenter-gateway" format="default" sectionFormat="of" derivedContent="DC-GATEWAY"/>.</li> <li pn="section-3.1-3.2">When Router E advertises theprefix-SIDPrefix-SID SID(E) of prefixP(E)P(E), itMUST<bcp14>MUST</bcp14> also advertise theencapsulationegress endpoint address and thetunnelencapsulation type of any tunnel used to reach E. This information is flooded domainwide.</t> <t>Ifwide. </li> <li pn="section-3.1-3.3">If A and E are in different routingdomainsdomains, then the informationMUST<bcp14>MUST</bcp14> be flooded into both domains. How this is achieved depends on the advertisement mechanism being used. The objective is that router A knows the characteristics of router E that originated the advertisement ofSID(E).</t> <t>RouterSID(E).</li> <li pn="section-3.1-3.4"> <t pn="section-3.1-3.4.1">Router A programs the FIB entry for prefix P(E) corresponding to the SID(E) according to whether a pop or swap action is advertised for the prefix. The resulting action may be:<list style="symbols"> <t>pop</t> <ul spacing="normal" bare="false" empty="false" pn="section-3.1-3.4.2"> <li pn="section-3.1-3.4.2.1">pop the toplabel</t> <t>swaplabel</li> <li pn="section-3.1-3.4.2.2">swap the top label to a value equal to SID(E) plus the lower bound of the SRGB ofE</t> </list></t> </list></t> <t>OnceE</li> </ul> </li> </ul> <t pn="section-3.1-4">Once constructed, the FIB can be used by a router to tell it how to process packets. It encapsulates the packets according to the appropriate encapsulation advertised for the segment and thenitsends the packets towards the next hop NHi.</t> <section anchor="fibeg"title="FIBnumbered="true" toc="include" removeInRFC="false" pn="section-3.1.1"> <name slugifiedName="name-fib-construction-example">FIB ConstructionExample"> <t>ThisExample</name> <t pn="section-3.1.1-1">This section is non-normative and provides a worked example of how a FIB might be constructed using OSPF andISISIS-IS extensions. It is based on the process described in <xref target="fib"/>.</t> <t> <list style="symbols"> <t>Routerformat="default" sectionFormat="of" derivedContent="Section 3.1"/>.</t> <ul spacing="normal" bare="false" empty="false" pn="section-3.1.1-2"> <li pn="section-3.1.1-2.1">Router E is SR-MPLS capable, so it advertises a Segment Routing Global Block (SRGB) using <xreftarget="OSPF-EXTENSIONS"/>target="RFC8665" format="default" sectionFormat="of" derivedContent="RFC8665"/> or <xreftarget="ISIS-EXTENSIONS"/>.</t> <t>Whentarget="RFC8667" format="default" sectionFormat="of" derivedContent="RFC8667"/>.</li> <li pn="section-3.1.1-2.2">When Router E advertises theprefix-SIDPrefix-SID SID(E) of prefixP(E)P(E), it also advertises the encapsulation endpoint address and the tunnel type of any tunnel used to reach E using <xreftarget="ISIS-ENCAP"/>target="I-D.ietf-isis-encapsulation-cap" format="default" sectionFormat="of" derivedContent="ISIS-ENCAP"/> or <xreftarget="OSPF-ROUTER"/>.</t> <t>Iftarget="I-D.ietf-ospf-encapsulation-cap" format="default" sectionFormat="of" derivedContent="OSPF-ENCAP"/>.</li> <li pn="section-3.1.1-2.3"> <t pn="section-3.1.1-2.3.1">If A and E are in differentdomainsdomains, then the information is flooded into both domains and any intervening domains.<list style="symbols"> <t>The</t> <ul spacing="normal" bare="false" empty="false" pn="section-3.1.1-2.3.2"> <li pn="section-3.1.1-2.3.2.1">The OSPF TunnelEncapsulationEncapsulations TLV <xreftarget="OSPF-ROUTER"/>target="I-D.ietf-ospf-encapsulation-cap" format="default" sectionFormat="of" derivedContent="OSPF-ENCAP"/> or theISISIS-IS Tunnel Encapsulation Type sub-TLV <xreftarget="ISIS-ENCAP"/>target="I-D.ietf-isis-encapsulation-cap" format="default" sectionFormat="of" derivedContent="ISIS-ENCAP"/> is floodeddomain-wide.</t> <t>Thedomain wide.</li> <li pn="section-3.1.1-2.3.2.2">The OSPFSID/label rangeSID/Label Range TLV <xreftarget="OSPF-EXTENSIONS"/>target="RFC8665" format="default" sectionFormat="of" derivedContent="RFC8665"/> or theISISIS-IS SR-CapabilitiesSub-TLVsub-TLV <xreftarget="ISIS-EXTENSIONS"/>target="RFC8667" format="default" sectionFormat="of" derivedContent="RFC8667"/> is advertiseddomain-widedomain wide so that router A knows the characteristics of routerE.</t> <t>WhenE.</li> <li pn="section-3.1.1-2.3.2.3"> <t pn="section-3.1.1-2.3.2.3.1">When router E advertises the prefix P(E):<list style="symbols"> <t>If</t> <ul spacing="normal" bare="false" empty="false" pn="section-3.1.1-2.3.2.3.2"> <li pn="section-3.1.1-2.3.2.3.2.1">If router E is runningISISIS-IS, it uses the extended reachability TLV (TLVs 135, 235, 236, 237) and associates the IPv4/IPv6 or IPv4/IPv6source routerSource Router ID sub-TLV(s) <xreftarget="RFC7794"/>.</t> <t>Iftarget="RFC7794" format="default" sectionFormat="of" derivedContent="RFC7794"/>.</li> <li pn="section-3.1.1-2.3.2.3.2.2">If router E is runningOSPFOSPF, it uses the OSPFv2 Extended Prefix OpaqueLSALink-State Advertisement (LSA) <xreftarget="RFC7684"/>target="RFC7684" format="default" sectionFormat="of" derivedContent="RFC7684"/> and sets the flooding scope toAS-wide.</t> </list></t> <t>IfAutonomous System (AS) wide.</li> </ul> </li> <li pn="section-3.1.1-2.3.2.4">If router E is runningISISIS-IS and advertises theISIS capabilityIS-IS Router CAPABILITY TLV (TLV 242) <xreftarget="RFC7981"/>,target="RFC7981" format="default" sectionFormat="of" derivedContent="RFC7981"/>, it sets the"router-ID""Router ID" field to a valid value or includes anIPV6IPv6 TErouter-IDRouter ID sub-TLV (TLV 12), or it does both. The "S" bit (flooding scope) of theISIS capabilityIS-IS Router CAPABILITY TLV (TLV 242) is set to"1" .</t> </list></t> <t>Router"1".</li> </ul> </li> <li pn="section-3.1.1-2.4"> <t pn="section-3.1.1-2.4.1">Router A programs the FIB entry for prefix P(E) corresponding to the SID(E) according to whether a pop or swap action is advertised for the prefix as follows:<list style="symbols"> <t>If</t> <ul spacing="normal" bare="false" empty="false" pn="section-3.1.1-2.4.2"> <li pn="section-3.1.1-2.4.2.1"> <t pn="section-3.1.1-2.4.2.1.1">If theNP flagNo-PHP (NP) Flag in OSPF or theP flagPersistent (P) Flag inISISIS-IS is clear:<list style="empty"> <t>pop</t> <ul empty="true" spacing="normal" bare="false" pn="section-3.1.1-2.4.2.1.2"> <li pn="section-3.1.1-2.4.2.1.2.1">pop the toplabel</t> </list></t> <t>Iflabel</li> </ul> </li> <li pn="section-3.1.1-2.4.2.2"> <t pn="section-3.1.1-2.4.2.2.1">If theNP flagNo-PHP (NP) Flag in OSPF or theP flagPersistent (P) Flag inISISIS-IS is set:<list style="empty"> <t>swap</t> <ul empty="true" spacing="normal" bare="false" pn="section-3.1.1-2.4.2.2.2"> <li pn="section-3.1.1-2.4.2.2.2.1">swap the top label to a value equal to SID(E) plus the lower bound of the SRGB ofE</t> </list></t> </list></t> </list></t> <t>WhenE</li> </ul> </li> </ul> </li> </ul> <t pn="section-3.1.1-3">When forwarding the packet according to the constructed FIBentryentry, the router encapsulates the packet according to the encapsulation as advertised using the mechanisms described in <xreftarget="ISIS-ENCAP"/>target="I-D.ietf-isis-encapsulation-cap" format="default" sectionFormat="of" derivedContent="ISIS-ENCAP"/> or <xreftarget="OSPF-ROUTER"/>).target="I-D.ietf-ospf-encapsulation-cap" format="default" sectionFormat="of" derivedContent="OSPF-ENCAP"/>. It then sends the packets towards the next hop NHi.</t><t>Note<t pn="section-3.1.1-4">Note that <xreftarget="RFC7510"/>target="RFC7510" format="default" sectionFormat="of" derivedContent="RFC7510"/> specifies the use of port number 6635 to indicate that the payload of a UDP packet is MPLS, and port number 6636 forMPLS-in-UDPMPLS-over-UDP utilizing DTLS. However, <xreftarget="ISIS-ENCAP"/>target="I-D.ietf-isis-encapsulation-cap" format="default" sectionFormat="of" derivedContent="ISIS-ENCAP"/> and <xreftarget="OSPF-ROUTER"/>target="I-D.ietf-ospf-encapsulation-cap" format="default" sectionFormat="of" derivedContent="OSPF-ENCAP"/> provide dynamic protocol mechanisms to configure the use of any Dynamic Port for a tunnel that uses UDP encapsulation. Nothing in this document prevents the use of an IGP or any other mechanism to negotiate the use of a Dynamic Port when UDP encapsulation is used for SR-MPLS, but if no such mechanism isusedused, then the port numbers specified in <xreftarget="RFC7510"/>target="RFC7510" format="default" sectionFormat="of" derivedContent="RFC7510"/> are used.</t> </section> </section> <section anchor="fwd"title="Packet Forwarding Procedures"> <t><xref target="RFC7510"/>numbered="true" toc="include" removeInRFC="false" pn="section-3.2"> <name slugifiedName="name-packet-forwarding-procedure">Packet-Forwarding Procedures</name> <t pn="section-3.2-1"><xref target="RFC7510" format="default" sectionFormat="of" derivedContent="RFC7510"/> specifies an IP-based encapsulation for MPLS, i.e.,MPLS-in-UDP.MPLS-over-UDP. This approach is applicable where IP-based encapsulation for MPLS is required and further fine-grained load balancing of MPLS packets over IP networks overEqual-Cost Multipath (ECMP)ECMP and/orLink Aggregation Groups (LAGs)LAGs is also required. This section provides details about the forwarding procedure when UDP encapsulation is adopted forSR-MPLS over IP.SR-MPLS-over-IP. Other encapsulation andtunnellingtunneling mechanisms can be applied using similar techniques, but forclarityclarity, this section uses UDP encapsulation as the exemplar.</t><t>Nodes<t pn="section-3.2-2">Nodes that are SR-MPLS capable can process SR-MPLS packets. Not all of the nodes in an SR-MPLS domain are SR-MPLS capable. Some nodes may be "legacy routers" that cannot handle SR-MPLS packets but can forward IP packets.An SR-MPLS-capableA nodeMAYcapable of SR-MPLS <bcp14>MAY</bcp14> advertise its capabilities using the IGP as described in <xreftarget="procs"/>.target="procs" format="default" sectionFormat="of" derivedContent="Section 3"/>. There are six types ofnodenodes in an SR-MPLS domain:<list style="symbols"> <t>Domain</t> <ul spacing="normal" bare="false" empty="false" pn="section-3.2-3"> <li pn="section-3.2-3.1">Domain ingress nodes that receive packets and encapsulate them for transmission across the domain. Those packets may be any payload protocol including native IP packets or packets that are already MPLSencapsulated.</t> <t>Legacyencapsulated.</li> <li pn="section-3.2-3.2">Legacy transit nodes that are IP routers but that are not SR-MPLS capable (i.e., are not able to performsegment routing).</t> <t>TransitSegment Routing).</li> <li pn="section-3.2-3.3">Transit nodes that are SR-MPLS capable but that are not identified by a SID in the SIDstack.</t> <t>Transitstack.</li> <li pn="section-3.2-3.4">Transit nodes that are SR-MPLS capable and need to perform SR-MPLS routing because they are identified by a SID in the SIDstack.</t> <t>Thestack.</li> <li pn="section-3.2-3.5">The penultimateSR-MPLS capablenode capable of SR-MPLS on the path that processes the last SID on the stack on behalf of the domain egressnode.</t> <t>Thenode.</li> <li pn="section-3.2-3.6">The domain egress node that forwards the payload packet for ultimatedelivery.</t> </list></t>delivery.</li> </ul> <section anchor="phpfwd"title="Packetnumbered="true" toc="include" removeInRFC="false" pn="section-3.2.1"> <name slugifiedName="name-packet-forwarding-with-penu">Packet Forwarding with Penultimate HopPopping"> <t>ThePopping</name> <t pn="section-3.2.1-1">The description in this section assumes that the label associated with eachprefix-SIDPrefix-SID is advertised by the owner of theprefix-SIDPrefix-SID as a PenultimateHop PoppingHop-Popping (PHP) label. That is, if one of the IGP flooding mechanisms is used, theNP flagNP-Flag in OSPF or theP flagP-Flag inISISIS-IS associated with theprefix-SIDPrefix-SID is not set.</t> <figure anchor="phpfwdeg"title="Packet Forwardingalign="left" suppress-title="false" pn="figure-3"> <name slugifiedName="name-packet-forwarding-example-w">Packet-Forwarding Example withPHP">PHP</name> <artworkalign="center"><![CDATA[align="center" name="" type="" alt="" pn="section-3.2.1-2.1"> +-----+ +-----+ +-----+ +-----+ +-----+ | A +-------+ B +-------+ C +-------+ D +-------+ H | +-----+ +--+--+ +--+--+ +--+--+ +-----+ | | | | | | +--+--+ +--+--+ +--+--+ | E +-------+ F +-------+ G | +-----+ +-----+ +-----+ +--------+|IP(A->E)||IP(A->E)| +--------+ +--------+ +--------+ | UDP ||IP(E->G)| |IP(G->H)||IP(E->G)| |IP(G->H)| +--------+ +--------+ +--------+ | L(G) | | UDP | | UDP | +--------+ +--------+ +--------+ | L(H) | | L(H) | |Exp Null| +--------+ +--------+ +--------+ | Packet |--->---> | Packet |--->---> | Packet | +--------+ +--------+ +--------+]]></artwork></artwork> </figure><t>In<t pn="section-3.2.1-3">In the example shown in <xreftarget="phpfwdeg"/>,target="phpfwdeg" format="default" sectionFormat="of" derivedContent="Figure 3"/>, assume that routers A, E,GG, and H areSR-MPLS-capablecapable of SR-MPLS while the remaining routers (B, C,DD, and F) are only capable of forwarding IP packets. Routers A, E, G, and H advertise their Segment Routing related information, such as via IS-IS or OSPF.</t><t>Now<t pn="section-3.2.1-4">Now assume that router A (the Domain ingress) wants to send a packet to router H (the Domain egress) via the explicit path {E->G->H}. Router A will impose an MPLS label stack on the packet that corresponds to that explicit path. Since the next hop toward router E is onlyIP-capableIP capable (B is a legacy transit node), router A replaces the top label (that indicated router E) with a UDP-based tunnel for MPLS (i.e., MPLS-over-UDP <xreftarget="RFC7510"/>)target="RFC7510" format="default" sectionFormat="of" derivedContent="RFC7510"/>) to router E and then sends the packet. In other words, router A pops the top label and then encapsulates the MPLS packet in a UDP tunnel to router E.</t><t>When<t pn="section-3.2.1-5">When the IP-encapsulated MPLS packet arrives at router E (which isan SR-MPLS-capablea transitnode),node capable of SR-MPLS), router E strips the IP-based tunnel header and then processes the decapsulated MPLS packet. The top label indicates that the packet must be forwarded toward router G. Since the next hop toward router G is onlyIP-capable,IP capable, router E replaces the current top label with an MPLS-over-UDP tunnel toward router G and sends it out. That is, router E pops the top label and then encapsulates the MPLS packet in a UDP tunnel to router G.</t><t>When<t pn="section-3.2.1-6">When the packet arrives at router G, router G will strip the IP-based tunnel header and then process the decapsulated MPLS packet. The top label indicates that the packet must be forwarded toward router H. Since the next hop toward router H is onlyIP-capableIP capable (D is a legacy transit router), router G would replace the current top label with an MPLS-over-UDP tunnel toward router H and send it out. However, since router G reaches the bottom of the label stack (G is the penultimateSR-MPLS capablenode capable of SR-MPLS on thepath)path), this would leave the original packet that router A wanted to send to router H encapsulated in UDP as if it was MPLS (i.e., with a UDP header and destination port indicating MPLS) even though the original packet could have been any protocol. That is, the final SR-MPLS has been popped exposing the payload packet.</t><t>To<t pn="section-3.2.1-7">To handle this, when a router (here it is router G) pops the final SR-MPLS label, it inserts an explicitnullNULL label <xreftarget="RFC3032"/>target="RFC3032" format="default" sectionFormat="of" derivedContent="RFC3032"/> before encapsulating the packet in an MPLS-over-UDP tunnel toward router H and sending it out. That is, router G pops the top label, discovers it has reached the bottom of stack, pushes an explicitnullNULL label, and then encapsulates the MPLS packet in a UDP tunnel to router H.</t> </section> <section anchor="nophpfwd"title="Packetnumbered="true" toc="include" removeInRFC="false" pn="section-3.2.2"> <name slugifiedName="name-packet-forwarding-without-p">Packet Forwarding without Penultimate HopPopping"> <t><xref target="nophpfwdeg"/>Popping</name> <t pn="section-3.2.2-1"><xref target="nophpfwdeg" format="default" sectionFormat="of" derivedContent="Figure 4"/> demonstrates the packet walk in the case where the label associated with eachprefix-SIDPrefix-SID advertised by the owner of theprefix-SIDPrefix-SID is not a PenultimateHop PoppingHop-Popping (PHP) label (e.g., thethe NP flagNP-Flag in OSPF or theP flagP-Flag inISISIS-IS associated with theprefix-SIDPrefix-SID is set). Apart from the PHPfunctionfunction, the roles of the routersisare unchanged from <xreftarget="phpfwd"/>.</t>target="phpfwd" format="default" sectionFormat="of" derivedContent="Section 3.2.1"/>.</t> <figure anchor="nophpfwdeg"title="Packet Forwardingalign="left" suppress-title="false" pn="figure-4"> <name slugifiedName="name-packet-forwarding-example-wi">Packet-Forwarding Example withoutPHP">PHP</name> <artworkalign="center"><![CDATA[align="center" name="" type="" alt="" pn="section-3.2.2-2.1"> +-----+ +-----+ +-----+ +-----+ +-----+ | A +-------+ B +-------+ C +--------+ D +--------+ H | +-----+ +--+--+ +--+--+ +--+--+ +-----+ | | | | | | +--+--+ +--+--+ +--+--+ | E +-------+ F +--------+ G | +-----+ +-----+ +-----+ +--------+|IP(A->E)||IP(A->E)| +--------+ +--------+ | UDP ||IP(E->G)||IP(E->G)| +--------+ +--------+ +--------+ | L(E) | | UDP ||IP(G->H)||IP(G->H)| +--------+ +--------+ +--------+ | L(G) | | L(G) | | UDP | +--------+ +--------+ +--------+ | L(H) | | L(H) | | L(H) | +--------+ +--------+ +--------+ | Packet |--->---> | Packet |--->---> | Packet | +--------+ +--------+ +--------+]]></artwork></artwork> </figure><t>As<t pn="section-3.2.2-3">As can be seen from the figure, the SR-MPLS label for each segment is left in place until the end of the segment where it is popped and the next instruction is processed.</t> </section> <section anchor="addnlfwd"title="Additionalnumbered="true" toc="include" removeInRFC="false" pn="section-3.2.3"> <name slugifiedName="name-additional-forwarding-proce">Additional ForwardingProcedures"> <t><list style="hanging"> <t hangText="Non-MPLS Interfaces:">AlthoughProcedures</name> <dl newline="false" spacing="normal" pn="section-3.2.3-1"> <dt pn="section-3.2.3-1.1">Non-MPLS Interfaces:</dt> <dd pn="section-3.2.3-1.2">Although the description in the previous two sections is based on the use ofprefix-SIDs,Prefix-SIDs, tunneling SR-MPLS packets is useful when the top label of a received SR-MPLS packet indicates anadjacency-SIDAdjacency SID and the corresponding adjacent node to thatadjacency-SIDAdjacency SID is not capable of MPLS forwarding but can still process SR-MPLS packets. In thisscenarioscenario, the top label would be replaced by an IP tunnel toward that adjacent node and then forwarded over the corresponding link indicated by theadjacency-SID.</t> <t hangText="When to use IP-based Tunnels:">TheAdjacency SID.</dd> <dt pn="section-3.2.3-1.3">When to Use IP-Based Tunnels:</dt> <dd pn="section-3.2.3-1.4">The description in the previous two sections is based on the assumption that an MPLS-over-UDP tunnel is used when thenexthopnext hop towards the next segment is notMPLS-enabled.MPLS enabled. However, even in the case where thenexthopnext hop towards the next segment isMPLS-capable,MPLS capable, an MPLS-over-UDP tunnel towards the next segment could still be used instead due to local policies. For instance, in the example as described in <xreftarget="nophpfwdeg"/>,target="nophpfwdeg" format="default" sectionFormat="of" derivedContent="Figure 4"/>, assume F is nowan SR-MPLS-capablea transit node capable of SR-MPLS while all the other assumptions remainunchanged:unchanged; since F is not identified by a SID in the stack and an MPLS-over-UDP tunnel is preferred to an MPLS LSP according to local policies, router E replaces the current top label with an MPLS-over-UDP tunnel toward router G andsendsends it out. (Note that if an MPLS LSP was preferred, the packet would be forwarded as nativeSR-MPLS.)</t> <t hangText="IPSR-MPLS.)</dd> <dt pn="section-3.2.3-1.5">IP HeaderFields:">WhenFields:</dt> <dd pn="section-3.2.3-1.6">When encapsulating an MPLS packet in UDP, the resulting packet is further encapsulated in IP for transmission. IPv4 or IPv6 may be used according to the capabilities of the network. The address fields are set as described in <xreftarget="usecases"/>.target="usecases" format="default" sectionFormat="of" derivedContent="Section 2"/>. The other IP header fields (such as the ECN field <xreftarget="RFC6040"/>, the DSCP code point <xref target="RFC2983"/>,target="RFC6040" format="default" sectionFormat="of" derivedContent="RFC6040"/>, the Differentiated Services Code Point (DSCP) <xref target="RFC2983" format="default" sectionFormat="of" derivedContent="RFC2983"/>, or IPv6 Flow Label) on each UDP-encapsulated segmentSHOULD<bcp14>SHOULD</bcp14> be configurable according to theoperator's policy:operator's policy; they may be copied from the header of the incoming packet; they may be promoted from the header of the payload packet; they may be set according to instructions programmed to be associated with the SID; or they may be configured dependent on the outgoing interface and payload. The TTL field setting in the encapsulating packet header is handled as described in[RFC7510]<xref target="RFC7510" format="default" sectionFormat="of" derivedContent="RFC7510"/>, which refers to[RFC4023].</t> <t hangText="Entropy and ECMP:">When<xref target="RFC4023" format="default" sectionFormat="of" derivedContent="RFC4023"/>.</dd> <dt pn="section-3.2.3-1.7">Entropy and ECMP:</dt> <dd pn="section-3.2.3-1.8">When encapsulating an MPLS packet with an IP tunnel header that is capable of encoding entropy (such as <xreftarget="RFC7510"/>),target="RFC7510" format="default" sectionFormat="of" derivedContent="RFC7510"/>), the corresponding entropy field (the source port in the case of a UDP tunnel)MAY<bcp14>MAY</bcp14> be filled with an entropy value that is generated by the encapsulator to uniquely identify a flow. However, what constitutes a flow is locally determined by the encapsulator. For instance, if the MPLS label stack contains at least one entropy label and the encapsulator is capable of reading that entropy label, the entropy label value could be directly copied to the source port of the UDP header. Otherwise, the encapsulator may have to perform a hash on the whole label stack or the five-tuple of the SR-MPLS payload if the payload is determined as an IP packet. To avoidre-performingrecalculating the hash or hunting for the entropy label each time the packet is encapsulated in a UDPtunneltunnel, itMAY<bcp14>MAY</bcp14> be desirable that the entropy value contained in the incoming packet (i.e., the UDP source port value) is retained when stripping the UDP header and isre-usedreused as the entropy value of the outgoingpacket.</t> <t hangText="Congestion Considerations:">Section 5 ofpacket.</dd> <dt pn="section-3.2.3-1.9">Congestion Considerations:</dt> <dd pn="section-3.2.3-1.10"> <xref target="RFC7510"/>sectionFormat="of" section="5" format="default" derivedLink="https://rfc-editor.org/rfc/rfc7510#section-5" derivedContent="RFC7510"/> provides a detailed analysis of the implications of congestion in MPLS-over-UDP systems and builds onsection 3.1.3 of<xref target="RFC8085"/> thatsectionFormat="of" section="3.1.3" format="default" derivedLink="https://rfc-editor.org/rfc/rfc8085#section-3.1.3" derivedContent="RFC8085"/>, which describes the congestion implications of UDP tunnels. All of those considerations apply to SR-MPLS-over-UDP tunnels as described in this document. In particular, it should be noted that the traffic carried in SR-MPLS flows is likely to be IPtraffic.</t> </list></t>traffic.</dd> </dl> </section> </section> </section> <section anchor="IANA"title="IANA Considerations"> <t>Thisnumbered="true" toc="include" removeInRFC="false" pn="section-4"> <name slugifiedName="name-iana-considerations">IANA Considerations</name> <t pn="section-4-1">This documentmakeshas norequests forIANAaction.</t>actions.</t> </section> <section anchor="Security"title="Security Considerations"> <t>Thenumbered="true" toc="include" removeInRFC="false" pn="section-5"> <name slugifiedName="name-security-considerations">Security Considerations</name> <t pn="section-5-1">The security consideration of <xreftarget="RFC8354"/>target="RFC8354" format="default" sectionFormat="of" derivedContent="RFC8354"/> (which redirects the reader to <xref target="RFC5095"/>)format="default" sectionFormat="of" derivedContent="RFC5095"/>) and <xreftarget="RFC7510"/>target="RFC7510" format="default" sectionFormat="of" derivedContent="RFC7510"/> apply. DTLS <xreftarget="RFC6347"/> SHOULDtarget="RFC6347" format="default" sectionFormat="of" derivedContent="RFC6347"/> <bcp14>SHOULD</bcp14> be used where security is needed on anMPLS-SR-over-UDPSR-MPLS-over-UDP segment including when the IP segment crosses the public Internet or some other untrusted environment. <xref target="RFC8402"/>format="default" sectionFormat="of" derivedContent="RFC8402"/> provides security considerations for Segment Routing, andSection 8.1 of that document<xref target="RFC8402" sectionFormat="of" section="8.1" format="default" derivedLink="https://rfc-editor.org/rfc/rfc8402#section-8.1" derivedContent="RFC8402"/> is particularly applicable to SR-MPLS.</t><t>It<t pn="section-5-2">It is difficult for an attacker to pass a rawMPLS encodedMPLS-encoded packet into anetworknetwork, and operators have considerable experienceatin excluding such packets at the network boundaries, forexampleexample, by excluding all packets that are revealed to be carrying an MPLS packet as the payload of IP tunnels. Further discussion of MPLS security is found in <xref target="RFC5920"/>.</t> <t>Itformat="default" sectionFormat="of" derivedContent="RFC5920"/>.</t> <t pn="section-5-3">It is easy for a network ingress node to detect any attempt to smuggle an IP packet into the network since it would see that the UDP destination port was set to MPLS, and such filteringSHOULD<bcp14>SHOULD</bcp14> be applied. If, however, the mechanisms described in <xreftarget="OSPF-EXTENSIONS"/>target="RFC8665" format="default" sectionFormat="of" derivedContent="RFC8665"/> or <xreftarget="ISIS-EXTENSIONS"/>target="RFC8667" format="default" sectionFormat="of" derivedContent="RFC8667"/> are applied, a wider variety of UDP port numbers might be in use making port filtering harder.</t><t>SR<t pn="section-5-4">SR packets not having a destination address terminating in the network would be transparently carried and would pose no different security risk to the network under consideration than any other traffic.</t><t>Where control plane<t pn="section-5-5">Where control-plane techniques are used (as described in <xreftarget="procs"/>),target="procs" format="default" sectionFormat="of" derivedContent="Section 3"/>), it is important that these protocols are adequately secured for the environment in which they are run as discussed in <xref target="RFC6862"/>format="default" sectionFormat="of" derivedContent="RFC6862"/> and <xref target="RFC5920"/>.</t> </section> <section title="Contributors"> <figure> <artwork><![CDATA[Ahmed Bashandy Individual Email: abashandy.ietf@gmail.com Clarence Filsfils Cisco Email: cfilsfil@cisco.com John Drake Juniper Email: jdrake@juniper.net Shaowen Ma Mellanox Technologies Email: mashaowen@gmail.com Mach Chen Huawei Email: mach.chen@huawei.com Hamid Assarpour Broadcom Email:hamid.assarpour@broadcom.com Robert Raszuk Bloomberg LP Email: robert@raszuk.net Uma Chunduri Huawei Email: uma.chunduri@gmail.com Luis M. Contreras Telefonica I+D Email: luismiguel.contrerasmurillo@telefonica.com Luay Jalil Verizon Email: luay.jalil@verizon.com Gunter Van De Velde Nokia Email: gunter.van_de_velde@nokia.com Tal Mizrahi Marvell Email: talmi@marvell.com Jeff Tantsura Individual Email: jefftant@gmail.com ]]></artwork> </figure> </section> <section anchor="Acknowledgements" title="Acknowledgements"> <t>Thanks to Joel Halpern, Bruno Decraene, Loa Andersson, Ron Bonica, Eric Rosen, Jim Guichard, Gunter Van De Velde, Andy Malis, Robert Sparks, and Al Morton for their insightful comments on this draft.</t> <t>Additional thanks to Mirja Kuehlewind, Alvaro Retana, Spencer Dawkins, Benjamin Kaduk, Martin Vigoureux, Suresh Krishnan, and Éric Vyncke for careful reviews and resulting comments.</t>format="default" sectionFormat="of" derivedContent="RFC5920"/>.</t> </section> </middle> <back> <displayreference target="I-D.ietf-bess-datacenter-gateway" to="DC-GATEWAY"/> <displayreference target="I-D.ietf-ospf-encapsulation-cap" to="OSPF-ENCAP"/> <displayreference target="I-D.ietf-isis-encapsulation-cap" to="ISIS-ENCAP"/> <displayreference target="I-D.ietf-6man-segment-routing-header" to="IPv6-SRH"/> <referencestitle="Normative References"> <?rfc include="reference.RFC.2119"?> <?rfc include="reference.RFC.3031"?> <?rfc include="reference.RFC.3032"?> <?rfc include="reference.RFC.4023"?> <?rfc include="reference.RFC.5095"?> <?rfc include="reference.RFC.6040"?> <?rfc include="reference.RFC.6347"?> <?rfc include="reference.RFC.7510"?> <?rfc include="reference.RFC.7684"?> <?rfc include="reference.RFC.7794"?> <?rfc include="reference.RFC.7981"?> <?rfc include="reference.RFC.8174"?> <?rfc include="reference.RFC.8402"?> <!-- <?rfc include="reference.I-D.ietf-spring-segment-routing-mpls"?>; companion document RFC YYYY-->pn="section-6"> <name slugifiedName="name-references">References</name> <references pn="section-6.1"> <name slugifiedName="name-normative-references">Normative References</name> <referenceanchor='RFCYYYY'>anchor="RFC2119" target="https://www.rfc-editor.org/info/rfc2119" quoteTitle="true" derivedAnchor="RFC2119"> <front><title>Segment Routing with MPLS data plane</title> <author initials='A' surname='Bashandy' fullname='Ahmed Bashandy'> <organization /> </author> <author initials='C' surname='Filsfils' fullname='Clarence Filsfils'> <organization /> </author> <author initials='S' surname='Previdi' fullname='Stefano Previdi'> <organization /> </author> <author initials='B' surname='Decraene' fullname='Bruno Decraene'> <organization /> </author> <author initials='S' surname='Litkowski' fullname='Stephane Litkowski'> <organization /> </author><title>Key words for use in RFCs to Indicate Requirement Levels</title> <authorinitials='R' surname='Shakir' fullname='Rob Shakir'>initials="S." surname="Bradner" fullname="S. Bradner"> <organization/>showOnFrontPage="true"/> </author> <datemonth='May' day='1' year='2019' /> <abstract><t>Segment Routing (SR) leveragesyear="1997" month="March"/> <abstract> <t>In many standards track documents several words are used to signify thesource routing paradigm. A node steers a packet through a controlled set of instructions, called segments, by prependingrequirements in thepacket with an SR header. In the MPLS dataplane, the SR header is instantiated through a label stack.specification. These words are often capitalized. This document defines these words as they should be interpreted in IETF documents. This document specifies an Internet Best Current Practices for theforwarding behavior to allow instantiating SR over the MPLS dataplane.</t></abstract>Internet Community, and requests discussion and suggestions for improvements.</t> </abstract> </front> <seriesInfo name="BCP" value="14"/> <seriesInfo name="RFC"value="YYYY"/>value="2119"/> <seriesInfo name="DOI"value="10.17487/RFCYYYY"/>value="10.17487/RFC2119"/> </reference></references> <references title="Informative References"> <?rfc include="reference.RFC.2983"?> <?rfc include="reference.RFC.5920"?> <?rfc include="reference.RFC.6790"?> <?rfc include="reference.RFC.6862"?> <?rfc include="reference.RFC.8085"?> <?rfc include="reference.RFC.8354"?> <!-- <?rfc include="reference.I-D.ietf-bess-datacenter-gateway"?>; I-D Exists --><referenceanchor='DATACENTER-GATEWAY'>anchor="RFC3031" target="https://www.rfc-editor.org/info/rfc3031" quoteTitle="true" derivedAnchor="RFC3031"> <front><title>Gateway Auto-Discovery and Route Advertisement<title>Multiprotocol Label Switching Architecture</title> <author initials="E." surname="Rosen" fullname="E. Rosen"> <organization showOnFrontPage="true"/> </author> <author initials="A." surname="Viswanathan" fullname="A. Viswanathan"> <organization showOnFrontPage="true"/> </author> <author initials="R." surname="Callon" fullname="R. Callon"> <organization showOnFrontPage="true"/> </author> <date year="2001" month="January"/> <abstract> <t>This document specifies the architecture forSegment Routing Enabled Domain Interconnection</title>Multiprotocol Label Switching (MPLS). [STANDARDS-TRACK]</t> </abstract> </front> <seriesInfo name="RFC" value="3031"/> <seriesInfo name="DOI" value="10.17487/RFC3031"/> </reference> <reference anchor="RFC3032" target="https://www.rfc-editor.org/info/rfc3032" quoteTitle="true" derivedAnchor="RFC3032"> <front> <title>MPLS Label Stack Encoding</title> <author initials="E." surname="Rosen" fullname="E. Rosen"> <organization showOnFrontPage="true"/> </author> <authorinitials='A' surname='Farrel' fullname='Adrian Farrel'>initials="D." surname="Tappan" fullname="D. Tappan"> <organization/>showOnFrontPage="true"/> </author> <authorinitials='J' surname='Drake' fullname='John Drake'>initials="G." surname="Fedorkow" fullname="G. Fedorkow"> <organization/>showOnFrontPage="true"/> </author> <authorinitials='E' surname='Rosen' fullname='Eric Rosen'>initials="Y." surname="Rekhter" fullname="Y. Rekhter"> <organization/>showOnFrontPage="true"/> </author> <authorinitials='K' surname='Patel' fullname='Keyur Patel'>initials="D." surname="Farinacci" fullname="D. Farinacci"> <organization/>showOnFrontPage="true"/> </author> <authorinitials='L' surname='Jalil' fullname='Luay Jalil'>initials="T." surname="Li" fullname="T. Li"> <organization showOnFrontPage="true"/> </author> <author initials="A." surname="Conta" fullname="A. Conta"> <organization/>showOnFrontPage="true"/> </author> <datemonth='February' day='26' year='2019' /> <abstract><t>Data centers are critical components ofyear="2001" month="January"/> <abstract> <t>This document specifies theinfrastructureencoding to be used bynetwork operators to provide services to their customers. Data centers are attachedan LSR in order tothe Internet or a backbone network by gateway routers. Onetransmit labeled packets on Point-to-Point Protocol (PPP) datacenter typically has more than one gateway for commercial, load balancing,links, on LAN data links, andresiliency reasons. Segment Routing is a popular protocol mechanism for use within apossibly on other datacenter, butlinks as well. This document also specifies rules and procedures forsteering traffic that flows between two data center sites. In order that one data center site may load balanceprocessing thetraffic it sends to another data center site,various fields of the label stack encoding. [STANDARDS-TRACK]</t> </abstract> </front> <seriesInfo name="RFC" value="3032"/> <seriesInfo name="DOI" value="10.17487/RFC3032"/> </reference> <reference anchor="RFC4023" target="https://www.rfc-editor.org/info/rfc4023" quoteTitle="true" derivedAnchor="RFC4023"> <front> <title>Encapsulating MPLS in IP or Generic Routing Encapsulation (GRE)</title> <author initials="T." surname="Worster" fullname="T. Worster"> <organization showOnFrontPage="true"/> </author> <author initials="Y." surname="Rekhter" fullname="Y. Rekhter"> <organization showOnFrontPage="true"/> </author> <author initials="E." surname="Rosen" fullname="E. Rosen" role="editor"> <organization showOnFrontPage="true"/> </author> <date year="2005" month="March"/> <abstract> <t>Various applications of MPLS make use of label stacks with multiple entries. In some cases, itneedsis possible toknowreplace thecomplete settop label ofgateway routers attheremote data center, the points of connection from those gateways to the backbone network, and the connectivity acrossstack with an IP-based encapsulation, thereby enabling thebackbone network. Segment Routing may also be operated in other domains, such as access networks. Those domains also needapplication tobe connected across backbonerun over networksthrough gateways.that do not have MPLS enabled in their core routers. This documentdefines a mechanism using the BGP Tunnel Encapsulation attribute to allow each gateway router to advertise the routes to the prefixes in the Segment Routing domains to which it provides access,specifies two IP-based encapsulations: MPLS-in-IP andalso to advertise on behalf of each other gateway to the same SegmentMPLS-in-GRE (Generic Routingdomain.</t></abstract>Encapsulation). Each of these is applicable in some circumstances. [STANDARDS-TRACK]</t> </abstract> </front> <seriesInfoname='Work in Progress,' value='draft-ietf-bess-datacenter-gateway-02' />name="RFC" value="4023"/> <seriesInfo name="DOI" value="10.17487/RFC4023"/> </reference><!-- <?rfc include="reference.I-D.ietf-ospf-segment-routing-extensions"?>; RFC Ed Queue --><referenceanchor='OSPF-EXTENSIONS'>anchor="RFC5095" target="https://www.rfc-editor.org/info/rfc5095" quoteTitle="true" derivedAnchor="RFC5095"> <front><title>OSPF Extensions for Segment Routing</title> <author initials='P' surname='Psenak' fullname='Peter Psenak' role="editor"> <organization /> </author> <author initials='S' surname='Previdi' fullname='Stefano Previdi' role="editor"> <organization /> </author> <author initials='C' surname='Filsfils' fullname='Clarence Filsfils'> <organization /> </author> <author initials='H' surname='Gredler' fullname='Hannes Gredler'> <organization /> </author><title>Deprecation of Type 0 Routing Headers in IPv6</title> <authorinitials='R' surname='Shakir' fullname='Rob Shakir'>initials="J." surname="Abley" fullname="J. Abley"> <organization/>showOnFrontPage="true"/> </author> <authorinitials='W' surname='Henderickx' fullname='Wim Henderickx'>initials="P." surname="Savola" fullname="P. Savola"> <organization/>showOnFrontPage="true"/> </author> <authorinitials='J' surname='Tantsura' fullname='Jeff Tantsura'>initials="G." surname="Neville-Neil" fullname="G. Neville-Neil"> <organization/>showOnFrontPage="true"/> </author> <datemonth='December' day='5' year='2018' /> <abstract><t>Segmentyear="2007" month="December"/> <abstract> <t>The functionality provided by IPv6's Type 0 Routing(SR) allowsHeader can be exploited in order to achieve traffic amplification over aflexible definition of end-to-end paths within IGP topologies by encoding paths as sequences of topological sub-paths, called "segments". These segments are advertised byremote path for thelink-state routing protocols (IS-IS and OSPF).purposes of generating denial-of-service traffic. Thisdraft describesdocument updates theOSPFv2 extensions required for Segment Routing.</t></abstract>IPv6 specification to deprecate the use of IPv6 Type 0 Routing Headers, in light of this security concern. [STANDARDS-TRACK]</t> </abstract> </front> <seriesInfoname='Work in Progress,' value='draft-ietf-ospf-segment-routing-extensions-27' />name="RFC" value="5095"/> <seriesInfo name="DOI" value="10.17487/RFC5095"/> </reference><!-- <?rfc include="reference.I-D.ietf-isis-segment-routing-extensions"?>; RFC Ed Queue --><referenceanchor='ISIS-EXTENSIONS'>anchor="RFC6040" target="https://www.rfc-editor.org/info/rfc6040" quoteTitle="true" derivedAnchor="RFC6040"> <front><title>IS-IS Extensions for Segment Routing</title> <author initials='S' surname='Previdi' fullname='Stefano Previdi' role="editor"> <organization /> </author> <author initials='L' surname='Ginsberg' fullname='Les Ginsberg' role="editor"> <organization /> </author> <author initials='C' surname='Filsfils' fullname='Clarence Filsfils'> <organization /> </author> <author initials='A' surname='Bashandy' fullname='Ahmed Bashandy'> <organization /> </author> <author initials='H' surname='Gredler' fullname='Hannes Gredler'> <organization /> </author> <author initials='B' surname='Decraene' fullname='Bruno Decraene'><title>Tunnelling of Explicit Congestion Notification</title> <author initials="B." surname="Briscoe" fullname="B. Briscoe"> <organization/>showOnFrontPage="true"/> </author> <datemonth='May' day='19' year='2019' /> <abstract><t>Segment Routing (SR) allows for a flexible definition of end-to-end paths within IGP topologies by encoding paths as sequences of topological sub-paths, called "segments". These segments are advertised byyear="2010" month="November"/> <abstract> <t>This document redefines how thelink-state routing protocols (IS-IS and OSPF). This draft describesexplicit congestion notification (ECN) field of thenecessary IS-IS extensions that needIP header should be constructed on entry to and exit from any IP-in-IP tunnel. On encapsulation, it updates RFC 3168 to bring all IP-in-IP tunnels (v4 or v6) into line with RFC 4301 IPsec ECN processing. On decapsulation, it updates both RFC 3168 and RFC 4301 to add new behaviours for previously unused combinations of inner and outer headers. The new rules ensure the ECN field is correctly propagated across a tunnel whether it is used to signal one or two severity levels of congestion; whereas before, only one severity level was supported. Tunnel endpoints can beintroducedupdated in any order without affecting pre-existing uses of the ECN field, thus ensuring backward compatibility. Nonetheless, operators wanting to support two severity levels (e.g., forSegment Routing operatingpre-congestion notification -- PCN) can require compliance with this new specification. A thorough analysis of the reasoning for these changes and the implications is included. In the unlikely event that the new rules do not meet a specific need, RFC 4774 gives guidance onan MPLS data-plane.</t></abstract>designing alternate ECN semantics, and this document extends that to include tunnelling issues. [STANDARDS-TRACK]</t> </abstract> </front> <seriesInfoname='Work in Progress,' value='draft-ietf-isis-segment-routing-extensions-25' />name="RFC" value="6040"/> <seriesInfo name="DOI" value="10.17487/RFC6040"/> </reference><!-- <?rfc include="reference.I-D.ietf-ospf-encapsulation-cap"?>; RFC Ed Queue --><referenceanchor='OSPF-ROUTER'>anchor="RFC6347" target="https://www.rfc-editor.org/info/rfc6347" quoteTitle="true" derivedAnchor="RFC6347"> <front><title>The Tunnel Encapsulations OSPF Router Information</title> <author initials='X' surname='Xu' fullname='Xiaohu Xu' role="editor"> <organization /> </author> <author initials='B' surname='Decraene' fullname='Bruno Decraene' role="editor"> <organization /> </author> <author initials='R' surname='Raszuk' fullname='Robert Raszuk'> <organization /> </author> <author initials='L' surname='Contreras' fullname='Luis Contreras'><title>Datagram Transport Layer Security Version 1.2</title> <author initials="E." surname="Rescorla" fullname="E. Rescorla"> <organization showOnFrontPage="true"/> </author> <author initials="N." surname="Modadugu" fullname="N. Modadugu"> <organization/> </author> <author initials='L' surname='Jalil' fullname='Luay Jalil'> <organization />showOnFrontPage="true"/> </author> <datemonth='October' day='10' year='2017' /> <abstract><t>Networks use tunnels for a variety of reasons. A large varietyyear="2012" month="January"/> <abstract> <t>This document specifies version 1.2 oftunnel types are defined andthetunnel encapsulator router needsDatagram Transport Layer Security (DTLS) protocol. The DTLS protocol provides communications privacy for datagram protocols. The protocol allows client/server applications toselectcommunicate in atype of tunnel whichway that issupported by the tunnel decapsulator router. This document defines howdesigned toadvertise, in OSPF Router Information Link State Advertisement (LSAs),prevent eavesdropping, tampering, or message forgery. The DTLS protocol is based on thelistTransport Layer Security (TLS) protocol and provides equivalent security guarantees. Datagram semantics oftunnel encapsulations supportedthe underlying transport are preserved by thetunnel decapsulator.</t></abstract>DTLS protocol. This document updates DTLS 1.0 to work with TLS version 1.2. [STANDARDS-TRACK]</t> </abstract> </front> <seriesInfoname='Work in Progress,' value='draft-ietf-ospf-encapsulation-cap-09' />name="RFC" value="6347"/> <seriesInfo name="DOI" value="10.17487/RFC6347"/> </reference><!-- <?rfc include="reference.I-D.ietf-isis-encapsulation-cap"?>; Expired --><referenceanchor='ISIS-ENCAP'>anchor="RFC7510" target="https://www.rfc-editor.org/info/rfc7510" quoteTitle="true" derivedAnchor="RFC7510"> <front><title>Advertising Tunnelling Capability<title>Encapsulating MPLS inIS-IS</title> <author initials='X' surname='Xu' fullname='Xiaohu Xu' role="editor"> <organization /> </author>UDP</title> <authorinitials='B' surname='Decraene' fullname='Bruno Decraene'>initials="X." surname="Xu" fullname="X. Xu"> <organization/>showOnFrontPage="true"/> </author> <authorinitials='R' surname='Raszuk' fullname='Robert Raszuk'>initials="N." surname="Sheth" fullname="N. Sheth"> <organization/>showOnFrontPage="true"/> </author> <authorinitials='U' surname='Chunduri' fullname='Uma Chunduri'>initials="L." surname="Yong" fullname="L. Yong"> <organization/>showOnFrontPage="true"/> </author> <authorinitials='L' surname='Contreras' fullname='Luis Contreras'>initials="R." surname="Callon" fullname="R. Callon"> <organization/>showOnFrontPage="true"/> </author> <authorinitials='L' surname='Jalil' fullname='Luay Jalil'>initials="D." surname="Black" fullname="D. Black"> <organization/>showOnFrontPage="true"/> </author> <datemonth='April' day='24' year='2017' /> <abstract><t>Some networks use tunnelsyear="2015" month="April"/> <abstract> <t>This document specifies an IP-based encapsulation fora variety of reasons. A large variety of tunnel types are defined and the ingress needsMPLS, called MPLS-in-UDP for situations where UDP (User Datagram Protocol) encapsulation is preferred toselectdirect use of MPLS, e.g., to enable UDP-based ECMP (Equal-Cost Multipath) or link aggregation. The MPLS- in-UDP encapsulation technology must only be deployed within atypesingle network (with a single network operator) or networks oftunnel whichan adjacent set of cooperating network operators where traffic issupported bymanaged to avoid congestion, rather than over theegress. This document defines howInternet where congestion control is required. Usage restrictions apply toadvertise egress tunnel capabilities in IS-IS Router Capability TLV.</t></abstract>MPLS-in-UDP usage for traffic that is not congestion controlled and to UDP zero checksum usage with IPv6.</t> </abstract> </front> <seriesInfoname='Work in Progress,' value='draft-ietf-isis-encapsulation-cap-01' />name="RFC" value="7510"/> <seriesInfo name="DOI" value="10.17487/RFC7510"/> </reference><!-- <?rfc include="reference.I-D.ietf-mpls-spring-entropy-label"?>; RFC Ed Queue --><referenceanchor='ENTROPY-LABEL'>anchor="RFC7684" target="https://www.rfc-editor.org/info/rfc7684" quoteTitle="true" derivedAnchor="RFC7684"> <front><title>Entropy label for SPRING tunnels</title><title>OSPFv2 Prefix/Link Attribute Advertisement</title> <authorinitials='S' surname='Kini' fullname='Sriganesh Kini'>initials="P." surname="Psenak" fullname="P. Psenak"> <organization/>showOnFrontPage="true"/> </author> <authorinitials='K' surname='Kompella' fullname='Kireeti Kompella'>initials="H." surname="Gredler" fullname="H. Gredler"> <organization/>showOnFrontPage="true"/> </author> <authorinitials='S' surname='Sivabalan' fullname='Siva Sivabalan'>initials="R." surname="Shakir" fullname="R. Shakir"> <organization/>showOnFrontPage="true"/> </author> <authorinitials='S' surname='Litkowski' fullname='Stephane Litkowski'>initials="W." surname="Henderickx" fullname="W. Henderickx"> <organization/>showOnFrontPage="true"/> </author> <authorinitials='R' surname='Shakir' fullname='Rob Shakir'>initials="J." surname="Tantsura" fullname="J. Tantsura"> <organization/>showOnFrontPage="true"/> </author> <authorinitials='J' surname='Tantsura' fullname='Jeff Tantsura'>initials="A." surname="Lindem" fullname="A. Lindem"> <organization/>showOnFrontPage="true"/> </author> <datemonth='July' day='16' year='2018' /> <abstract><t>Segment Routing (SR) leverages the source routing paradigm. A node steers a packet through an ordered list of instructions, called segments. Segment Routingyear="2015" month="November"/> <abstract> <t>OSPFv2 requires functional extension beyond what can readily beapplied todone with theMulti Protocol Label Switching (MPLS) data plane. Entropy label (EL) is a technique usedfixed-format Link State Advertisements (LSAs) as described inMPLS to improve load-balancing.RFC 2328. This documentexamines and describes how ELs are todefines OSPFv2 Opaque LSAs based on Type-Length-Value (TLV) tuples that can beappliedused toSegment Routing MPLS.</t></abstract>associate additional attributes with prefixes or links. Depending on the application, these prefixes and links may or may not be advertised in the fixed-format LSAs. The OSPFv2 Opaque LSAs are optional and fully backward compatible.</t> </abstract> </front> <seriesInfoname='Work in Progress,' value='draft-ietf-mpls-spring-entropy-label-12' />name="RFC" value="7684"/> <seriesInfo name="DOI" value="10.17487/RFC7684"/> </reference><!-- <?rfc include="reference.I-D.ietf-6man-segment-routing-header"?>; AD Evaluation::Revised I-D Needed for 2 days --><referenceanchor='IPV6-SEGMENT'>anchor="RFC7794" target="https://www.rfc-editor.org/info/rfc7794" quoteTitle="true" derivedAnchor="RFC7794"> <front><title>IPv6 Segment Routing Header (SRH)</title> <author initials='C' surname='Filsfils' fullname='Clarence Filsfils' role="editor"> <organization /> </author><title>IS-IS Prefix Attributes for Extended IPv4 and IPv6 Reachability</title> <authorinitials='D' surname='Dukes' fullname='Darren Dukes'initials="L." surname="Ginsberg" fullname="L. Ginsberg" role="editor"> <organization/>showOnFrontPage="true"/> </author> <authorinitials='S' surname='Previdi' fullname='Stefano Previdi'>initials="B." surname="Decraene" fullname="B. Decraene"> <organization/>showOnFrontPage="true"/> </author> <authorinitials='J' surname='Leddy' fullname='John Leddy'>initials="S." surname="Previdi" fullname="S. Previdi"> <organization/>showOnFrontPage="true"/> </author> <authorinitials='S' surname='Matsushima' fullname='Satoru Matsushima'>initials="X." surname="Xu" fullname="X. Xu"> <organization/>showOnFrontPage="true"/> </author> <authorinitials='d' surname='daniel.voyer@bell.ca' fullname='daniel.voyer@bell.ca'>initials="U." surname="Chunduri" fullname="U. Chunduri"> <organization/>showOnFrontPage="true"/> </author> <datemonth='June' day='13' year='2019' /> <abstract><t>Segment Routing can be appliedyear="2016" month="March"/> <abstract> <t>This document introduces new sub-TLVs tothesupport advertisement of IPv4 and IPv6data plane using a new typeprefix attribute flags and the source router ID ofRouting Extension Header. This document describestheSegment Routing Extension Header and how it is used by Segment Routing capable nodes.</t></abstract>router that originated a prefix advertisement.</t> </abstract> </front> <seriesInfoname='Work in Progress,' value='draft-ietf-6man-segment-routing-header-21' /> </reference> </references>name="RFC" value="7794"/> <seriesInfo name="DOI" value="10.17487/RFC7794"/> </reference> <reference anchor="RFC7981" target="https://www.rfc-editor.org/info/rfc7981" quoteTitle="true" derivedAnchor="RFC7981"> <front> <title>IS-IS Extensions for Advertising Router Information</title> <author initials="L." surname="Ginsberg" fullname="L. Ginsberg"> <organization showOnFrontPage="true"/> </author> <author initials="S." surname="Previdi" fullname="S. Previdi"> <organization showOnFrontPage="true"/> </author> <author initials="M." surname="Chen" fullname="M. Chen"> <organization showOnFrontPage="true"/> </author> <date year="2016" month="October"/> <abstract> <t>This document defines a new optional Intermediate System to Intermediate System (IS-IS) TLV named CAPABILITY, formed of multiple sub-TLVs, which allows a router to announce its capabilities within an IS-IS level or the entire routing domain. This document obsoletes RFC 4971.</t> </abstract> </front> <seriesInfo name="RFC" value="7981"/> <seriesInfo name="DOI" value="10.17487/RFC7981"/> </reference> <reference anchor="RFC8174" target="https://www.rfc-editor.org/info/rfc8174" quoteTitle="true" derivedAnchor="RFC8174"> <front> <title>Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words</title> <author initials="B." surname="Leiba" fullname="B. Leiba"> <organization showOnFrontPage="true"/> </author> <date year="2017" month="May"/> <abstract> <t>RFC 2119 specifies common key words that may be used in protocol specifications. This document aims to reduce the ambiguity by clarifying that only UPPERCASE usage of the key words have the defined special meanings.</t> </abstract> </front> <seriesInfo name="BCP" value="14"/> <seriesInfo name="RFC" value="8174"/> <seriesInfo name="DOI" value="10.17487/RFC8174"/> </reference> <reference anchor="RFC8402" target="https://www.rfc-editor.org/info/rfc8402" quoteTitle="true" derivedAnchor="RFC8402"> <front> <title>Segment Routing Architecture</title> <author initials="C." surname="Filsfils" fullname="C. Filsfils" role="editor"> <organization showOnFrontPage="true"/> </author> <author initials="S." surname="Previdi" fullname="S. Previdi" role="editor"> <organization showOnFrontPage="true"/> </author> <author initials="L." surname="Ginsberg" fullname="L. Ginsberg"> <organization showOnFrontPage="true"/> </author> <author initials="B." surname="Decraene" fullname="B. Decraene"> <organization showOnFrontPage="true"/> </author> <author initials="S." surname="Litkowski" fullname="S. Litkowski"> <organization showOnFrontPage="true"/> </author> <author initials="R." surname="Shakir" fullname="R. Shakir"> <organization showOnFrontPage="true"/> </author> <date year="2018" month="July"/> <abstract> <t>Segment Routing (SR) leverages the source routing paradigm. A node steers a packet through an ordered list of instructions, called "segments". A segment can represent any instruction, topological or service based. A segment can have a semantic local to an SR node or global within an SR domain. SR provides a mechanism that allows a flow to be restricted to a specific topological path, while maintaining per-flow state only at the ingress node(s) to the SR domain.</t> <t>SR can be directly applied to the MPLS architecture with no change to the forwarding plane. A segment is encoded as an MPLS label. An ordered list of segments is encoded as a stack of labels. The segment to process is on the top of the stack. Upon completion of a segment, the related label is popped from the stack.</t> <t>SR can be applied to the IPv6 architecture, with a new type of routing header. A segment is encoded as an IPv6 address. An ordered list of segments is encoded as an ordered list of IPv6 addresses in the routing header. The active segment is indicated by the Destination Address (DA) of the packet. The next active segment is indicated by a pointer in the new routing header.</t> </abstract> </front> <seriesInfo name="RFC" value="8402"/> <seriesInfo name="DOI" value="10.17487/RFC8402"/> </reference> <reference anchor="RFC8660" target="https://www.rfc-editor.org/info/rfc8660" quoteTitle="true" derivedAnchor="RFC8660"> <front> <title>Segment Routing with the MPLS Data Plane</title> <seriesInfo name="RFC" value="8660"/> <seriesInfo name="DOI" value="10.17487/RFC8660"/> <author initials="A" surname="Bashandy" fullname="Ahmed Bashandy"> <organization showOnFrontPage="true"/> </author> <author initials="C" surname="Filsfils" fullname="Clarence Filsfils"> <organization showOnFrontPage="true"/> </author> <author initials="S" surname="Previdi" fullname="Stefano Previdi"> <organization showOnFrontPage="true"/> </author> <author initials="B" surname="Decraene" fullname="Bruno Decraene"> <organization showOnFrontPage="true"/> </author> <author initials="S" surname="Litkowski" fullname="Stephane Litkowski"> <organization showOnFrontPage="true"/> </author> <author initials="R" surname="Shakir" fullname="Rob Shakir"> <organization showOnFrontPage="true"/> </author> <date month="December" year="2019"/> </front> </reference> </references> <references pn="section-6.2"> <name slugifiedName="name-informative-references">Informative References</name> <reference anchor="I-D.ietf-bess-datacenter-gateway" quoteTitle="true" target="https://tools.ietf.org/html/draft-ietf-bess-datacenter-gateway-04" derivedAnchor="DC-GATEWAY"> <front> <title>Gateway Auto-Discovery and Route Advertisement for Segment Routing Enabled Domain Interconnection</title> <author initials="A" surname="Farrel" fullname="Adrian Farrel"> <organization showOnFrontPage="true"/> </author> <author initials="J" surname="Drake" fullname="John Drake"> <organization showOnFrontPage="true"/> </author> <author initials="E" surname="Rosen" fullname="Eric Rosen"> <organization showOnFrontPage="true"/> </author> <author initials="K" surname="Patel" fullname="Keyur Patel"> <organization showOnFrontPage="true"/> </author> <author initials="L" surname="Jalil" fullname="Luay Jalil"> <organization showOnFrontPage="true"/> </author> <date month="August" day="21" year="2019"/> <abstract> <t>Data centers are critical components of the infrastructure used by network operators to provide services to their customers. Data centers are attached to the Internet or a backbone network by gateway routers. One data center typically has more than one gateway for commercial, load balancing, and resiliency reasons. Segment Routing is a popular protocol mechanism for use within a data center, but also for steering traffic that flows between two data center sites. In order that one data center site may load balance the traffic it sends to another data center site, it needs to know the complete set of gateway routers at the remote data center, the points of connection from those gateways to the backbone network, and the connectivity across the backbone network. Segment Routing may also be operated in other domains, such as access networks. Those domains also need to be connected across backbone networks through gateways. This document defines a mechanism using the BGP Tunnel Encapsulation attribute to allow each gateway router to advertise the routes to the prefixes in the Segment Routing domains to which it provides access, and also to advertise on behalf of each other gateway to the same Segment Routing domain.</t> </abstract> </front> <seriesInfo name="Internet-Draft" value="draft-ietf-bess-datacenter-gateway-04"/> <format type="TXT" target="http://www.ietf.org/internet-drafts/draft-ietf-bess-datacenter-gateway-04.txt"/> <refcontent>Work in Progress</refcontent> </reference> <reference anchor="I-D.ietf-6man-segment-routing-header" quoteTitle="true" target="https://tools.ietf.org/html/draft-ietf-6man-segment-routing-header-26" derivedAnchor="IPv6-SRH"> <front> <title>IPv6 Segment Routing Header (SRH)</title> <author initials="C" surname="Filsfils" fullname="Clarence Filsfils"> <organization showOnFrontPage="true"/> </author> <author initials="D" surname="Dukes" fullname="Darren Dukes"> <organization showOnFrontPage="true"/> </author> <author initials="S" surname="Previdi" fullname="Stefano Previdi"> <organization showOnFrontPage="true"/> </author> <author initials="J" surname="Leddy" fullname="John Leddy"> <organization showOnFrontPage="true"/> </author> <author initials="S" surname="Matsushima" fullname="Satoru Matsushima"> <organization showOnFrontPage="true"/> </author> <author initials="D" surname="Voyer" fullname="Daniel Voyer"> <organization showOnFrontPage="true"/> </author> <date month="October" day="22" year="2019"/> <abstract> <t>Segment Routing can be applied to the IPv6 data plane using a new type of Routing Extension Header called the Segment Routing Header. This document describes the Segment Routing Header and how it is used by Segment Routing capable nodes.</t> </abstract> </front> <seriesInfo name="Internet-Draft" value="draft-ietf-6man-segment-routing-header-26"/> <format type="TXT" target="http://www.ietf.org/internet-drafts/draft-ietf-6man-segment-routing-header-26.txt"/> <refcontent>Work in Progress</refcontent> </reference> <reference anchor="I-D.ietf-isis-encapsulation-cap" quoteTitle="true" target="https://tools.ietf.org/html/draft-ietf-isis-encapsulation-cap-01" derivedAnchor="ISIS-ENCAP"> <front> <title>Advertising Tunnelling Capability in IS-IS</title> <author initials="X" surname="Xu" fullname="Xiaohu Xu"> <organization showOnFrontPage="true"/> </author> <author initials="B" surname="Decraene" fullname="Bruno Decraene"> <organization showOnFrontPage="true"/> </author> <author initials="R" surname="Raszuk" fullname="Robert Raszuk"> <organization showOnFrontPage="true"/> </author> <author initials="U" surname="Chunduri" fullname="Uma Chunduri"> <organization showOnFrontPage="true"/> </author> <author initials="L" surname="Contreras" fullname="Luis Contreras"> <organization showOnFrontPage="true"/> </author> <author initials="L" surname="Jalil" fullname="Luay Jalil"> <organization showOnFrontPage="true"/> </author> <date month="April" day="24" year="2017"/> <abstract> <t>Some networks use tunnels for a variety of reasons. A large variety of tunnel types are defined and the ingress needs to select a type of tunnel which is supported by the egress. This document defines how to advertise egress tunnel capabilities in IS-IS Router Capability TLV.</t> </abstract> </front> <seriesInfo name="Internet-Draft" value="draft-ietf-isis-encapsulation-cap-01"/> <format type="TXT" target="http://www.ietf.org/internet-drafts/draft-ietf-isis-encapsulation-cap-01.txt"/> <refcontent>Work in Progress</refcontent> </reference> <reference anchor="I-D.ietf-ospf-encapsulation-cap" quoteTitle="true" target="https://tools.ietf.org/html/draft-ietf-ospf-encapsulation-cap-09" derivedAnchor="OSPF-ENCAP"> <front> <title>The Tunnel Encapsulations OSPF Router Information</title> <author initials="X" surname="Xu" fullname="Xiaohu Xu"> <organization showOnFrontPage="true"/> </author> <author initials="B" surname="Decraene" fullname="Bruno Decraene"> <organization showOnFrontPage="true"/> </author> <author initials="R" surname="Raszuk" fullname="Robert Raszuk"> <organization showOnFrontPage="true"/> </author> <author initials="L" surname="Contreras" fullname="Luis Contreras"> <organization showOnFrontPage="true"/> </author> <author initials="L" surname="Jalil" fullname="Luay Jalil"> <organization showOnFrontPage="true"/> </author> <date month="October" day="10" year="2017"/> <abstract> <t>Networks use tunnels for a variety of reasons. A large variety of tunnel types are defined and the tunnel encapsulator router needs to select a type of tunnel which is supported by the tunnel decapsulator router. This document defines how to advertise, in OSPF Router Information Link State Advertisement (LSAs), the list of tunnel encapsulations supported by the tunnel decapsulator.</t> </abstract> </front> <seriesInfo name="Internet-Draft" value="draft-ietf-ospf-encapsulation-cap-09"/> <format type="TXT" target="http://www.ietf.org/internet-drafts/draft-ietf-ospf-encapsulation-cap-09.txt"/> <refcontent>Work in Progress</refcontent> </reference> <reference anchor="RFC2983" target="https://www.rfc-editor.org/info/rfc2983" quoteTitle="true" derivedAnchor="RFC2983"> <front> <title>Differentiated Services and Tunnels</title> <author initials="D." surname="Black" fullname="D. Black"> <organization showOnFrontPage="true"/> </author> <date year="2000" month="October"/> <abstract> <t>This document considers the interaction of Differentiated Services (diffserv) with IP tunnels of various forms. This memo provides information for the Internet community.</t> </abstract> </front> <seriesInfo name="RFC" value="2983"/> <seriesInfo name="DOI" value="10.17487/RFC2983"/> </reference> <reference anchor="RFC5920" target="https://www.rfc-editor.org/info/rfc5920" quoteTitle="true" derivedAnchor="RFC5920"> <front> <title>Security Framework for MPLS and GMPLS Networks</title> <author initials="L." surname="Fang" fullname="L. Fang" role="editor"> <organization showOnFrontPage="true"/> </author> <date year="2010" month="July"/> <abstract> <t>This document provides a security framework for Multiprotocol Label Switching (MPLS) and Generalized Multiprotocol Label Switching (GMPLS) Networks. This document addresses the security aspects that are relevant in the context of MPLS and GMPLS. It describes the security threats, the related defensive techniques, and the mechanisms for detection and reporting. This document emphasizes RSVP-TE and LDP security considerations, as well as inter-AS and inter-provider security considerations for building and maintaining MPLS and GMPLS networks across different domains or different Service Providers. This document is not an Internet Standards Track specification; it is published for informational purposes.</t> </abstract> </front> <seriesInfo name="RFC" value="5920"/> <seriesInfo name="DOI" value="10.17487/RFC5920"/> </reference> <reference anchor="RFC6790" target="https://www.rfc-editor.org/info/rfc6790" quoteTitle="true" derivedAnchor="RFC6790"> <front> <title>The Use of Entropy Labels in MPLS Forwarding</title> <author initials="K." surname="Kompella" fullname="K. Kompella"> <organization showOnFrontPage="true"/> </author> <author initials="J." surname="Drake" fullname="J. Drake"> <organization showOnFrontPage="true"/> </author> <author initials="S." surname="Amante" fullname="S. Amante"> <organization showOnFrontPage="true"/> </author> <author initials="W." surname="Henderickx" fullname="W. Henderickx"> <organization showOnFrontPage="true"/> </author> <author initials="L." surname="Yong" fullname="L. Yong"> <organization showOnFrontPage="true"/> </author> <date year="2012" month="November"/> <abstract> <t>Load balancing is a powerful tool for engineering traffic across a network. This memo suggests ways of improving load balancing across MPLS networks using the concept of "entropy labels". It defines the concept, describes why entropy labels are useful, enumerates properties of entropy labels that allow maximal benefit, and shows how they can be signaled and used for various applications. This document updates RFCs 3031, 3107, 3209, and 5036. [STANDARDS-TRACK]</t> </abstract> </front> <seriesInfo name="RFC" value="6790"/> <seriesInfo name="DOI" value="10.17487/RFC6790"/> </reference> <reference anchor="RFC6862" target="https://www.rfc-editor.org/info/rfc6862" quoteTitle="true" derivedAnchor="RFC6862"> <front> <title>Keying and Authentication for Routing Protocols (KARP) Overview, Threats, and Requirements</title> <author initials="G." surname="Lebovitz" fullname="G. Lebovitz"> <organization showOnFrontPage="true"/> </author> <author initials="M." surname="Bhatia" fullname="M. Bhatia"> <organization showOnFrontPage="true"/> </author> <author initials="B." surname="Weis" fullname="B. Weis"> <organization showOnFrontPage="true"/> </author> <date year="2013" month="March"/> <abstract> <t>Different routing protocols employ different mechanisms for securing protocol packets on the wire. While most already have some method for accomplishing cryptographic message authentication, in many cases the existing methods are dated, vulnerable to attack, and employ cryptographic algorithms that have been deprecated. The "Keying and Authentication for Routing Protocols" (KARP) effort aims to overhaul and improve these mechanisms. This document does not contain protocol specifications. Instead, it defines the areas where protocol specification work is needed. This document is a companion document to RFC 6518, "Keying and Authentication for Routing Protocols (KARP) Design Guidelines"; together they form the guidance and instruction KARP design teams will use to review and overhaul routing protocol transport security.</t> </abstract> </front> <seriesInfo name="RFC" value="6862"/> <seriesInfo name="DOI" value="10.17487/RFC6862"/> </reference> <reference anchor="RFC8085" target="https://www.rfc-editor.org/info/rfc8085" quoteTitle="true" derivedAnchor="RFC8085"> <front> <title>UDP Usage Guidelines</title> <author initials="L." surname="Eggert" fullname="L. Eggert"> <organization showOnFrontPage="true"/> </author> <author initials="G." surname="Fairhurst" fullname="G. Fairhurst"> <organization showOnFrontPage="true"/> </author> <author initials="G." surname="Shepherd" fullname="G. Shepherd"> <organization showOnFrontPage="true"/> </author> <date year="2017" month="March"/> <abstract> <t>The User Datagram Protocol (UDP) provides a minimal message-passing transport that has no inherent congestion control mechanisms. This document provides guidelines on the use of UDP for the designers of applications, tunnels, and other protocols that use UDP. Congestion control guidelines are a primary focus, but the document also provides guidance on other topics, including message sizes, reliability, checksums, middlebox traversal, the use of Explicit Congestion Notification (ECN), Differentiated Services Code Points (DSCPs), and ports.</t> <t>Because congestion control is critical to the stable operation of the Internet, applications and other protocols that choose to use UDP as an Internet transport must employ mechanisms to prevent congestion collapse and to establish some degree of fairness with concurrent traffic. They may also need to implement additional mechanisms, depending on how they use UDP.</t> <t>Some guidance is also applicable to the design of other protocols (e.g., protocols layered directly on IP or via IP-based tunnels), especially when these protocols do not themselves provide congestion control.</t> <t>This document obsoletes RFC 5405 and adds guidelines for multicast UDP usage.</t> </abstract> </front> <seriesInfo name="BCP" value="145"/> <seriesInfo name="RFC" value="8085"/> <seriesInfo name="DOI" value="10.17487/RFC8085"/> </reference> <reference anchor="RFC8354" target="https://www.rfc-editor.org/info/rfc8354" quoteTitle="true" derivedAnchor="RFC8354"> <front> <title>Use Cases for IPv6 Source Packet Routing in Networking (SPRING)</title> <author initials="J." surname="Brzozowski" fullname="J. Brzozowski"> <organization showOnFrontPage="true"/> </author> <author initials="J." surname="Leddy" fullname="J. Leddy"> <organization showOnFrontPage="true"/> </author> <author initials="C." surname="Filsfils" fullname="C. Filsfils"> <organization showOnFrontPage="true"/> </author> <author initials="R." surname="Maglione" fullname="R. Maglione" role="editor"> <organization showOnFrontPage="true"/> </author> <author initials="M." surname="Townsley" fullname="M. Townsley"> <organization showOnFrontPage="true"/> </author> <date year="2018" month="March"/> <abstract> <t>The Source Packet Routing in Networking (SPRING) architecture describes how Segment Routing can be used to steer packets through an IPv6 or MPLS network using the source routing paradigm. This document illustrates some use cases for Segment Routing in an IPv6-only environment.</t> </abstract> </front> <seriesInfo name="RFC" value="8354"/> <seriesInfo name="DOI" value="10.17487/RFC8354"/> </reference> <reference anchor="RFC8662" target="https://www.rfc-editor.org/info/rfc8662" quoteTitle="true" derivedAnchor="RFC8662"> <front> <title>Entropy Label for Source Packet Routing in Networking (SPRING) Tunnels</title> <seriesInfo name="RFC" value="8662"/> <seriesInfo name="DOI" value="10.17487/RFC8662"/> <author initials="S" surname="Kini" fullname="Sriganesh Kini"> <organization showOnFrontPage="true"/> </author> <author initials="K" surname="Kompella" fullname="Kireeti Kompella"> <organization showOnFrontPage="true"/> </author> <author initials="S" surname="Sivabalan" fullname="Siva Sivabalan"> <organization showOnFrontPage="true"/> </author> <author initials="S" surname="Litkowski" fullname="Stephane Litkowski"> <organization showOnFrontPage="true"/> </author> <author initials="R" surname="Shakir" fullname="Rob Shakir"> <organization showOnFrontPage="true"/> </author> <author initials="J" surname="Tantsura" fullname="Jeff Tantsura"> <organization showOnFrontPage="true"/> </author> <date month="December" year="2019"/> </front> </reference> <reference anchor="RFC8665" target="https://www.rfc-editor.org/info/rfc8665" quoteTitle="true" derivedAnchor="RFC8665"> <front> <title>OSPF Extensions for Segment Routing</title> <seriesInfo name="RFC" value="8665"/> <seriesInfo name="DOI" value="10.17487/RFC8665"/> <author initials="P" surname="Psenak" fullname="Peter Psenak" role="editor"> <organization showOnFrontPage="true"/> </author> <author initials="S" surname="Previdi" fullname="Stefano Previdi" role="editor"> <organization showOnFrontPage="true"/> </author> <author initials="C" surname="Filsfils" fullname="Clarence Filsfils"> <organization showOnFrontPage="true"/> </author> <author initials="H" surname="Gredler" fullname="Hannes Gredler"> <organization showOnFrontPage="true"/> </author> <author initials="R" surname="Shakir" fullname="Rob Shakir"> <organization showOnFrontPage="true"/> </author> <author initials="W" surname="Henderickx" fullname="Wim Henderickx"> <organization showOnFrontPage="true"/> </author> <author initials="J" surname="Tantsura" fullname="Jeff Tantsura"> <organization showOnFrontPage="true"/> </author> <date month="December" year="2019"/> </front> </reference> <reference anchor="RFC8667" target="https://www.rfc-editor.org/info/rfc8667" quoteTitle="true" derivedAnchor="RFC8667"> <front> <title>IS-IS Extensions for Segment Routing</title> <seriesInfo name="RFC" value="8667"/> <seriesInfo name="DOI" value="10.17487/RFC8667"/> <author initials="S" surname="Previdi" fullname="Stefano Previdi" role="editor"> <organization showOnFrontPage="true"/> </author> <author initials="L" surname="Ginsberg" fullname="Les Ginsberg" role="editor"> <organization showOnFrontPage="true"/> </author> <author initials="C" surname="Filsfils" fullname="Clarence Filsfils"> <organization showOnFrontPage="true"/> </author> <author initials="A" surname="Bashandy" fullname="Ahmed Bashandy"> <organization showOnFrontPage="true"/> </author> <author initials="H" surname="Gredler" fullname="Hannes Gredler"> <organization showOnFrontPage="true"/> </author> <author initials="B" surname="Decraene" fullname="Bruno Decraene"> <organization showOnFrontPage="true"/> </author> <date month="December" year="2019"/> </front> </reference> </references> </references> <section anchor="Acknowledgements" numbered="false" toc="include" removeInRFC="false" pn="section-appendix.a"> <name slugifiedName="name-acknowledgements">Acknowledgements</name> <t pn="section-appendix.a-1">Thanks to Joel Halpern, Bruno Decraene, Loa Andersson, Ron Bonica, Eric Rosen, Jim Guichard, Gunter Van De Velde, Andy Malis, Robert Sparks, and Al Morton for their insightful comments on this document.</t> <t pn="section-appendix.a-2">Additional thanks to Mirja Kuehlewind, Alvaro Retana, Spencer Dawkins, Benjamin Kaduk, Martin Vigoureux, Suresh Krishnan, and Eric Vyncke for careful reviews and resulting comments.</t> </section> <section numbered="false" toc="include" removeInRFC="false" pn="section-appendix.b"> <name slugifiedName="name-contributors">Contributors</name> <artwork name="" type="" align="left" alt="" pn="section-appendix.b-1"> Ahmed Bashandy Individual Email: abashandy.ietf@gmail.com </artwork> <artwork name="" type="" align="left" alt="" pn="section-appendix.b-2"> Clarence Filsfils Cisco Email: cfilsfil@cisco.com </artwork> <artwork name="" type="" align="left" alt="" pn="section-appendix.b-3"> John Drake Juniper Email: jdrake@juniper.net </artwork> <artwork name="" type="" align="left" alt="" pn="section-appendix.b-4"> Shaowen Ma Mellanox Technologies Email: mashaowen@gmail.com </artwork> <artwork name="" type="" align="left" alt="" pn="section-appendix.b-5"> Mach Chen Huawei Email: mach.chen@huawei.com </artwork> <artwork name="" type="" align="left" alt="" pn="section-appendix.b-6"> Hamid Assarpour Broadcom Email:hamid.assarpour@broadcom.com </artwork> <artwork name="" type="" align="left" alt="" pn="section-appendix.b-7"> Robert Raszuk Bloomberg LP Email: robert@raszuk.net </artwork> <artwork name="" type="" align="left" alt="" pn="section-appendix.b-8"> Uma Chunduri Huawei Email: uma.chunduri@gmail.com </artwork> <artwork name="" type="" align="left" alt="" pn="section-appendix.b-9"> Luis M. Contreras Telefonica I+D Email: luismiguel.contrerasmurillo@telefonica.com </artwork> <artwork name="" type="" align="left" alt="" pn="section-appendix.b-10"> Luay Jalil Verizon Email: luay.jalil@verizon.com </artwork> <artwork name="" type="" align="left" alt="" pn="section-appendix.b-11"> Gunter Van De Velde Nokia Email: gunter.van_de_velde@nokia.com </artwork> <artwork name="" type="" align="left" alt="" pn="section-appendix.b-12"> Tal Mizrahi Marvell Email: talmi@marvell.com </artwork> <artwork name="" type="" align="left" alt="" pn="section-appendix.b-13"> Jeff Tantsura Apstra, Inc. Email: jefftant.ietf@gmail.com </artwork> </section> <section anchor="authors-addresses" numbered="false" removeInRFC="false" toc="include" pn="section-appendix.c"> <name slugifiedName="name-authors-addresses">Authors' Addresses</name> <author fullname="Xiaohu Xu" initials="X." surname="Xu"> <organization showOnFrontPage="true">Alibaba, Inc</organization> <address> <email>xiaohu.xxh@alibaba-inc.com</email> </address> </author> <author fullname="Stewart Bryant" initials="S." surname="Bryant"> <organization showOnFrontPage="true">Futurewei Technologies</organization> <address> <email>stewart.bryant@gmail.com</email> </address> </author> <author fullname="Adrian Farrel" initials="A." surname="Farrel"> <organization showOnFrontPage="true">Old Dog Consulting</organization> <address> <email>adrian@olddog.co.uk</email> </address> </author> <author fullname="Syed Hassan" initials="S." surname="Hassan"> <organization showOnFrontPage="true">Cisco</organization> <address> <email>shassan@cisco.com</email> </address> </author> <author fullname="Wim Henderickx" initials="W" surname="Henderickx"> <organization showOnFrontPage="true">Nokia</organization> <address> <email>wim.henderickx@nokia.com</email> </address> </author> <author fullname="Zhenbin Li" initials="Z." surname="Li"> <organization showOnFrontPage="true">Huawei</organization> <address> <email>lizhenbin@huawei.com</email> </address> </author> </section> </back> </rfc>