Link State Routing (lsr) Internet Drafts

      
 A YANG Data Model for OSPF Segment Routing for the MPLS Data Plane
 
 draft-ietf-ospf-sr-yang-32.txt
 Date: 04/12/2024
 Authors: Yingzhen Qu, Acee Lindem, Zhaohui Zhang, Helen Chen
 Working Group: Link State Routing (lsr)
 This document defines a YANG data module that can be used to configure and manage OSPF Extensions for Segment Routing for the MPLS data plane.
 A YANG Data Model for IS-IS Segment Routing for the MPLS Data Plane
 
 draft-ietf-isis-sr-yang-23.txt
 Date: 30/11/2024
 Authors: Stephane Litkowski, Yingzhen Qu, Pushpasis Sarkar, Helen Chen, Jeff Tantsura
 Working Group: Link State Routing (lsr)
 This document defines a YANG data module that can be used to configure and manage IS-IS Segment Routing for MPLS data plane.
 OSPF YANG Model Augmentations for Additional Features - Version 1
 
 draft-ietf-lsr-ospf-yang-augmentation-v1-13.txt
 Date: 01/07/2024
 Authors: Acee Lindem, Yingzhen Qu
 Working Group: Link State Routing (lsr)
 This document defines YANG data modules augmenting the IETF OSPF YANG model to provide support for Traffic Engineering Extensions to OSPF Version 3 as defined in RFC 5329, OSPF Two-Part Metric as defined in RFC 8042, OSPF Graceful Link Shutdown as defined in RFC 8379, OSPF Link-Local Signaling (LLS) Extensions for Local Interface ID Advertisement as defined in RFC 8510, OSPF MSD as defined in RFC 8476, OSPF Application-Specific Link Attributes as defined in RFC 9492, and OSPF Flexible Algorithm.
 Extensions to OSPF for Advertising Prefix Administrative Tags
 
 draft-ietf-lsr-ospf-admin-tags-23.txt
 Date: 17/12/2024
 Authors: Acee Lindem, Peter Psenak, Yingzhen Qu
 Working Group: Link State Routing (lsr)
 It is useful for routers in OSPFv2 and OSPFv3 routing domains to be able to associate tags with prefixes. Previously, OSPFv2 and OSPFv3 were relegated to a single tag and only for AS External and Not-So- Stubby-Area (NSSA) prefixes. With the flexible encodings provided by OSPFv2 Prefix/Link Attribute Advertisement and OSPFv3 Extended LSAs, multiple administrative tags may be advertised for all types of prefixes. These administrative tags can be used for many applications including route redistribution policy, selective prefix prioritization, selective IP Fast-ReRoute (IPFRR) prefix protection, and many others.
 IS-IS YANG Model Augmentations for Additional Features - Version 1
 
 draft-ietf-lsr-isis-yang-augmentation-v1-08.txt
 Date: 02/09/2024
 Authors: Acee Lindem, Yingzhen Qu, Stephane Litkowski
 Working Group: Link State Routing (lsr)
 This document defines YANG data modules augmenting the IETF IS-IS YANG model to provide support for IS-IS Minimum Remaining Lifetime as defined in RFC 7987, IS-IS Application-Specific Link Attributes as defined in RFC 9479, IS-IS Flexible Algorithm as defined in RFC 9350, and Signaling Maximum SID Depth Using IS-IS as defined in RFC 8491.
 Applicability of IS-IS Multi-Topology (MT) for Segment Routing based Network Resource Partition (NRP)
 
 draft-ietf-lsr-isis-sr-vtn-mt-08.txt
 Date: 18/08/2024
 Authors: Chongfeng Xie, Chenhao Ma, Jie Dong, Zhenbin Li
 Working Group: Link State Routing (lsr)
 Enhanced VPNs aim to deliver VPN services with enhanced characteristics, such as guaranteed resources, latency, jitter, etc., so as to support customers requirements for connectivity services with these enhanced characteristics. Enhanced VPN requires integration between the overlay VPN connectivity and the characteristics provided by the underlay network. A Network Resource Partition (NRP) is a subset of the network resources and associated policies on each of a connected set of links in the underlay network. An NRP could be used as the underlay to support one or a group of enhanced VPN services. In some network scenarios, each NRP can be associated with a unique logical network topology. This document describes a mechanism to build the SR-based NRPs using IS-IS Multi-Topology together with other well-defined IS-IS extensions.
 OSPF-GT (Generalized Transport)
 
 draft-ietf-lsr-ospf-transport-instance-08.txt
 Date: 08/12/2024
 Authors: Acee Lindem, Yingzhen Qu, Abhay Roy, Sina Mirtorabi
 Working Group: Link State Routing (lsr)
 OSPFv2 and OSPFv3 include a reliable flooding mechanism to disseminate routing topology and Traffic Engineering (TE) information within a routing domain. Given the effectiveness of these mechanisms, it is advantageous to use the same mechanism for dissemination of other types of information within the domain. However, burdening OSPF with this additional information will impact intra-domain routing convergence and possibly jeopardize the stability of the OSPF routing domain. This document presents mechanisms to advertise this non-routing information in separate OSPF Generalized Transport (OSPF-GT) instances. OSPF-GT is not constrained to the semantics as traditional OSPF. OSPF-GT neighbors are not required to be directly attached since they are never used to compute hop-by-hop routing. Consequently, independent sparse topologies can be defined to dissemenate non- routing information only to those OSPF-GT routers requiring it.
 Flexible Algorithms: Bandwidth,Delay,Metrics and Constraints
 
 draft-ietf-lsr-flex-algo-bw-con-17.txt
 Date: 04/12/2024
 Authors: Shraddha Hegde, William Britto, Rajesh Shetty, Bruno Decraene, Peter Psenak, Tony Li
 Working Group: Link State Routing (lsr)
 Many networks configure the link metric relative to the link capacity. High bandwidth traffic gets routed as per the link capacity. Flexible algorithms provide mechanisms to create constraint based paths in an IGP. This draft documents a generic metric type and set of bandwidth related constraints to be used in Flexible Algorithms.
 YANG Data Model for OSPF SRv6
 
 draft-ietf-lsr-ospf-srv6-yang-06.txt
 Date: 02/09/2024
 Authors: Zhibo Hu, Xuesong Geng, Syed Raza, Yingzhen Qu, Acee Lindem
 Working Group: Link State Routing (lsr)
 This document defines a YANG data model that can be used to configure and manage OSPFv3 Segment Routing over the IPv6 Data Plane.
 YANG Data Model for IS-IS SRv6
 
 draft-ietf-lsr-isis-srv6-yang-06.txt
 Date: 01/09/2024
 Authors: Zhibo Hu, Dan Ye, Yingzhen Qu, Xuesong Geng, Qiufang Ma
 Working Group: Link State Routing (lsr)
 This document defines a YANG data model that can be used to configure and manage IS-IS Segment Routing over the IPv6 Data Plane.
 IS-IS Distributed Flooding Reduction
 
 draft-ietf-lsr-distoptflood-07.txt
 Date: 19/10/2024
 Authors: Russ White, Shraddha Hegde, Tony Przygienda, Luay Jalil, Dan Voyer
 Working Group: Link State Routing (lsr)
 In dense topologies (such as data center fabrics based on the Clos and butterfly though not limited to those; in fact any large topology or one with relatively high degree of connectivity qualifies here) IGP flooding mechanisms designed originally for rather sparse topologies can "overflood", or in other words generate too many identical copies of same information arriving at a given node from other devices. This normally results in longer convergence times and higher resource utilization to process and discard the superfluous copies. Flooding algorithm extensions that restrict the amount of flooding performed can be constructed and can reduce resource utilization significantly, while improving convergence performance. One such flooding modification (based on previous art) optimized for operational considerations, described further in Section 2, is described in this document.
 IGP Flexible Algorithms Reverse Affinity Constraint
 
 draft-ietf-lsr-igp-flex-algo-reverse-affinity-03.txt
 Date: 09/09/2024
 Authors: Peter Psenak, Jakub Horn, Dhamija
 Working Group: Link State Routing (lsr)
 An IGP Flexible Algorithm (Flex-Algorithm) allows IGPs to compute constraint-based paths. This document extends IGP Flex-Algorithm with additional constraints.
 IGP Unreachable Prefix Announcement
 
 draft-ietf-lsr-igp-ureach-prefix-announce-03.txt
 Date: 14/10/2024
 Authors: Peter Psenak, Clarence Filsfils, Stephane Litkowski, Dan Voyer, Dhamija, Shraddha Hegde, Gunter Van de Velde, Gyan Mishra
 Working Group: Link State Routing (lsr)
 In the presence of summarization, there is a need to signal loss of reachability to an individual prefix covered by the summary in order to enable fast convergence away from paths to the node which owns the prefix which is no longer reachable. This document describes how to use the existing protocol mechanisms in IS-IS and OSPF, together with the two new flags, to advertise such prefix reachability loss.
 Multi-part TLVs in IS-IS
 
 draft-ietf-lsr-multi-tlv-06.txt
 Date: 25/09/2024
 Authors: Parag Kaneriya, Tony Li, Tony Przygienda, Shraddha Hegde, Les Ginsberg
 Working Group: Link State Routing (lsr)
 New technologies are adding new information into IS-IS while deployment scales are simultaneously increasing, causing the contents of many critical TLVs to exceed the currently supported limit of 255 octets. Extensions exist that require significant IS-IS changes that could help address the problem, but a less drastic solution would be beneficial. This document codifies the common mechanism of extending the TLV content space through multiple TLVs.
 Prefix Flag Extension for OSPFv2 and OSPFv3
 
 draft-ietf-lsr-ospf-prefix-extended-flags-03.txt
 Date: 09/10/2024
 Authors: Ran Chen, Detao Zhao, Peter Psenak, Ketan Talaulikar, Liyan Gong
 Working Group: Link State Routing (lsr)
 Within OSPF, each prefix is advertised along with an 8-bit field of capabilities, by using the Prefix Options (OSPFv3) and the flag flield in the OSPFv2 Extended Prefix TLV (OSPFv2). However, for OSPFv3, all the bits of the Prefix Options have already been assigned, and for OSPFv2, there are not many undefined bits left in the OSPFv2 Extended Prefix TLV. This document solves the problem of insufficient existing flags, and defines the variable length Prefix Attribute Flags Sub-TLVs for OSPFv2 and OSPFv3 respectively for the extended flag fields.
 Advertising Unreachable Links in OSPF
 
 draft-ietf-lsr-ospf-ls-link-infinity-02.txt
 Date: 09/12/2024
 Authors: Liyan Gong, Weiqiang Cheng, Changwang Lin, Acee Lindem, Ran Chen
 Working Group: Link State Routing (lsr)
 In certain scenarios, it is necessary to advertise unreachable links in OSPF, which should be explicitly excluded from the related SPF calculation. This document specifies using LSLinkInfinity(0xffff) to advertise an OSPF link as unreachable. Stub Router Advertisement (RFC 6987) defines MaxLinkMetric (0xffff) to indicate a router-LSA link should not be used for transit traffic. This document updates RFC 6987 and RFC 8770. When an OSPFv2 router supports the Unreachable Link support capability defined in this document, the OSPFv2 stub router MaxLinkMetric(0xffff) MUST be updated to MaxReachableLinkMetric(0xfffe).
 Updates to Anycast Property advertisement for OSPFv2
 
 draft-ietf-lsr-anycast-flag-01.txt
 Date: 20/10/2024
 Authors: Ran Chen, Detao Zhao, Peter Psenak, Ketan Talaulikar, Changwang Lin
 Working Group: Link State Routing (lsr)
 Both SR-MPLS prefix-SID and IPv4 prefix may be configured as anycast and as such the same value can be advertised by multiple routers. It is useful for other routers to know that the advertisement is for an anycast identifier. Each prefix is advertised along with an 8-bit field of capabilities,by using the flag flield in the OSPFv2 Extended Prefix TLV, but the definition of anycast flag to identify the prefix as anycast has not yet been defined. This document defines a new flag in the OSPFv2 Extended Prefix TLV Flags to advertise the anycast property.
 YANG Model for IS-IS Protocol Implementation Conformance Statement (PICS)
 
 draft-ietf-lsr-isis-pics-yang-00.txt
 Date: 03/11/2024
 Authors: Yingzhen Qu, Les Ginsberg, Tony Przygienda, Bruno Decraene, Yongqing Zhu
 Working Group: Link State Routing (lsr)
 The YANG model in this document is to be used to query an IS-IS Protocol Implementation Conformance Statement (PICS).
 YANG Data Model for IS-IS L2 Bundle Member Link Attributes PICS
 
 draft-ietf-lsr-isis-pics-l2member-attr-yang-00.txt
 Date: 03/11/2024
 Authors: Yingzhen Qu, Les Ginsberg, Tony Przygienda, Bruno Decraene, Yongqing Zhu
 Working Group: Link State Routing (lsr)
 The YANG model in this document is to query an IS-IS Protocol Implementation Conformance Statement (PICS) of advertising Layer 2 Bundle Member Link Attributes.
 YANG Data Model for IS-IS Segment Routing MPLS PICS
 
 draft-ietf-lsr-isis-pics-srmpls-yang-00.txt
 Date: 03/11/2024
 Authors: Yingzhen Qu, Les Ginsberg, Tony Przygienda, Bruno Decraene, Yongqing Zhu
 Working Group: Link State Routing (lsr)
 The YANG model in this document is to query an IS-IS Protocol Implementation Conformance Statement (PICS) of Segment Routing on MPLS data plane.

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Link State Routing (lsr)

WG Name Link State Routing
Acronym lsr
Area Routing Area (rtg)
State Active
Charter charter-ietf-lsr-01 Approved
Status update Show Changed 2019-03-24
Document dependencies
Additional resources Current WG Status
ISIS WG's Documents and RFCs
Issue tracker
OSPF WG's Documents and RFCs
Wiki
Zulip Stream
Personnel Chairs Acee Lindem, Christian Hopps, Yingzhen Qu
Area Director Gunter Van de Velde
Mailing list Address lsr@ietf.org
To subscribe https://www.ietf.org/mailman/listinfo/lsr
Archive https://mailarchive.ietf.org/arch/browse/lsr/
Chat Room address https://zulip.ietf.org/#narrow/stream/lsr

Charter for Working Group

The Link-State Routing (LSR) Working Group is chartered to document current protocol implementation practices and improvements, protocol usage scenarios, maintenance and extensions of the link-state interior gateway routing protocols (IGPs) - specifically IS-IS, OSPFv2, and OSPFv3. The LSR Working Group was formed by merging the isis and ospf WGs and assigning all their existing adopted work at the time of chartering to LSR.

IS-IS is an IGP specified and standardized by ISO through ISO 10589:2002 and additional RFC standards with extensions to support IP that has been deployed in the Internet for decades. For the IS-IS protocol, LSR-WG’s work is focused on IP routing, currently based on the agreement in RFC 3563 with ISO/JTC1/SC6. The LSR-WG will interact with other standards bodies that have responsibility for standardizing IS-IS. LSR-WG will continue to support Layer 2 routing (for example TRILL work) as needed.

OSPFv2 [RFC 2328 and extensions], is an IGP that has been deployed in the Internet for decades. OSPFv3 [RFC5340 and extensions] provides OSPF for IPv6 and IPv4 [RFC5838] which can be delivered over IPv6 or IPv4 [RFC 7949].

The LSR Working Group will generally manage its specific work items by milestones agreed with the responsible Area Director.

In addition to ongoing maintenance, the following topics are specific work-items for the WG.

1) Improve OSPF support for IPv6 and create at least parity with IPv4 functionality
by adding OSPFv3 extensions using the OSPFv3 Extended LSAs.

2) Extensions needed for Segment Routing and associated architectural changes

3) YANG models for the management of IS-IS, OSPFv2, and OSPFv3 and extensions

4) Extensions for source-destination routing

5) Improvements to flooding (and other behaviors) to better support dense meshed
network topologies, such as are commonly used in data centers.

The Link-State Routing (LSR) Working Group will coordinate with other working groups, such as RTGWG, SPRING, MPLS, TEAS, PCE, V6OPS, and 6MAN, to understand the need for extensions and to confirm that the planned work meets the needs and is compatible with IS-IS and/or OSPF from functional, architectural and performance point of views. LSR-WG will coordinate with CCAMP, TEAS, and BIER on their extensions to the LSR IGPs as applicable to LSR protocol operation and scale. LSR-WG should coordinate with other WGs as needed.

Milestones

Date Milestone Associated documents
Jan 2025 OSPF Segment Routing YANG Model draft-ietf-ospf-sr-yang
Jan 2025 IS-IS Segment Routing SR YANG Model draft-ietf-isis-sr-yang
Jan 2025 UPNEXT: Multi-part TLVs in IS-IS draft-ietf-lsr-multi-tlv
Jan 2025 UPNEXT: Extensions to OSPF for Advertising Prefix Administrative Tags
Feb 2024 WGLC: Flexible Algorithms: Bandwidth, Delay, Metrics and Constraints draft-ietf-lsr-flex-algo-bw-con
Jan 2024 SUBMITTED: YANG Model for OSPFv3 Extended LSAs rfc9587 (was draft-ietf-lsr-ospfv3-extended-lsa-yang)
Dec 2023 SUBMITTED: Area Proxy for IS-IS rfc9666 (was draft-ietf-lsr-isis-area-proxy)
Dec 2023 SUBMITTED: Dynamic Flooding on Dense Graphs rfc9667 (was draft-ietf-lsr-dynamic-flooding)
Sep 2023 SUBMITTED: IS-IS Fast Flooding rfc9681 (was draft-ietf-lsr-isis-fast-flooding)