Status update for WG lsr at IETF-103

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.

Current areas of interest in the LSR WG include:

 * Segment Routing Extensions: The IS-IS, OSPFv2, and OSPFv3 extensions for the MPLS data plane are all nearly completion. The are all dependent on a normative reference to the "Segment Routing in the MPLS Data Plane" draft. Extensions for Segment Routing on the IPv6 data plane are under way. The salient LSR Segment Routing drafts are:

   - OSPF Segment Routing Extensions - https://datatracker.ietf.org/doc/draft-ietf-ospf-segment-routing-extensions/
   - IS-IS Segment Routing Extensions - https://datatracker.ietf.org/doc/draft-ietf-isis-segment-routing-extensions/
   - OSPFv3 Segment Routing Extensions - https://datatracker.ietf.org/doc/draft-ietf-ospf-ospfv3-segment-routing-extensions/
   - Segment Routing in the MPLS Data Plane - https://datatracker.ietf.org/doc/draft-ietf-spring-segment-routing-mpls/
   - IS-IS Extensions to Support Routing over IPv6 Data Plane - https://datatracker.ietf.org/doc/draft-bashandy-isis-srv6-extensions/

* YANG Modeling: The base OSPF YANG Model has completed WG last call and is ready for publication request. The base IS-IS model will follow shortly. We have various model drafts for extensions that can be progressed now that the base models are nearly publication. The relevant YANG model drafts include:
    
    - YANG Data Model for OSPF Protocol - https://datatracker.ietf.org/doc/draft-ietf-ospf-yang/
    - YANG Data Model for IS-IS Protocol - https://datatracker.ietf.org/doc/draft-ietf-isis-yang-isis-cfg/
    - YANG Data Model for OSPF Segment Routing - https://datatracker.ietf.org/doc/draft-ietf-ospf-sr-yang/
    - YANG Data Model for IS-IS Segment Routing - https://datatracker.ietf.org/doc/draft-ietf-isis-sr-yang/
    - YANG Model for OSPFv3 Extended LSAs - https://datatracker.ietf.org/doc/draft-acee-lsr-ospfv3-extended-lsa-yang/

* Computation Optimizations: There are both WG documents and individual proposals to improve the LSR route computation. These include: 

    - IGP Flexible Algorithm - https://datatracker.ietf.org/doc/draft-ietf-lsr-flex-algo/
    - OSPF Routing with Cross-Address Family Traffic Engineering Tunnels - https://datatracker.ietf.org/doc/draft-ietf-ospf-xaf-te/
    - Preferred Path Routing (PPR) in IS-IS - https://datatracker.ietf.org/doc/draft-chunduri-lsr-isis-preferred-path-routing/
    - Preferred Path Routing (PPR) in OSPF - https://datatracker.ietf.org/doc/draft-chunduri-lsr-ospf-preferred-path-routing/
    - Preferred Path Route Graph Structure - https://datatracker.ietf.org/doc/draft-ce-lsr-ppr-graph/
  
 * Link Attribute Advertisement: OSPF and ISIS will allow application specific link attributes. 

    - IS-IS TE App - https://datatracker.ietf.org/doc/draft-ietf-isis-te-app/
    - OSPF Link Traffic Engineering (TE) Attribute Reuse - https://datatracker.ietf.org/doc/draft-ietf-ospf-te-link-attr-reuse/

 * Data Center (DC) Routing Optimizations: We have multiple proposals to reduce the flooding overhead in densely meshed data center topologies. Many of these will be presented at IETF 103 in Bangkok. A list of drafts in this area is included below:

    - IS-IS Spine Leaf - https://datatracker.ietf.org/doc/draft-shen-isis-spine-leaf-ext
    - Dynamic flooding - https://datatracker.ietf.org/doc/draft-li-lsr-dynamic-flooding
    - IS-IS Sparse Link-State Flooding - https://datatracker.ietf.org/doc/draft-hsmit-lsr-isis-dnfm
    - OSPF Flooding Reduction - https://datatracker.ietf.org/doc/draft-cc-ospf-flooding-reduction
    - Distributed Algorithm for Constrained IGP Flooding - https://datatracker.ietf.org/doc/draft-allan-lsr-flooding-algorithm-00
    - IS-IS Support for Openfabric - https://datatracker.ietf.org/doc/draft-white-openfabric/

  While there is much differentiation in these proposals there is also a significant amount of overlap. This is an area of WG debate and there may be in interim on the topic. 

At IETF 103, there will also be some key presentations relating to IS-IS protocol enhancements. These have been talked about in the past but no formal proposals have gone forward. These could be the start of some exciting new protocol enhancements: 

     - IS-IS over TCP - https://datatracker.ietf.org/doc/draft-hsmit-lsr-isis-flooding-over-tcp/
     - Level 1 IS-IS Area Abstraction - https://www.ietf.org/id/draft-li-area-abstraction-00.txt/
     - Hierarchial IS-IS - https://datatracker.ietf.org/doc/draft-li-hierarchical-isis/

Document Status:

  Since the last IETF in Montreal, there have not been in RFC published. However, the following drafts have have completed IESG review since Montreal and will be published "soon":

      - Signaling MSD (Maximum SID Depth) using IS-IS - https://datatracker.ietf.org/doc/draft-acee-lsr-ospfv3-extended-lsa-yang/
      - Signaling MSD (Maximum SID Depth) using IS-IS - https://datatracker.ietf.org/doc/draft-ietf-isis-segment-routing-msd/
      - OSPF LLS Extensions for Local Interface ID Advertisement - https://datatracker.ietf.org/doc/draft-ietf-ospf-lls-interface-id/
  
The following draft is currently in the IESG Evaluation process:

       - IS-IS Routing with Reverse Metric  - https://datatracker.ietf.org/doc/draft-ietf-isis-reverse-metric/

 The following draft is in IETF last call: 

         - OSPFv3 Segment Routing Extensions - https://datatracker.ietf.org/doc/draft-ietf-ospf-ospfv3-segment-routing-extensions/

   Publication has been requested for the following drat: 

         - H-bit Support for OSPFv2 - https://datatracker.ietf.org/doc/draft-ietf-ospf-ospfv2-hbit/


Date: November 1st, 2018
         

       

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