Session Date/Time: 07 Nov 2022 13:00

idr

Summary

The IDR working group meeting covered several topics, including updates on existing drafts, discussions on new proposals, and considerations for future directions. Key areas of focus included BGP-LS extensions, YANG modeling for BGP, deprecation of AS sets, and various BGP extensions for traffic steering and network slicing. There was significant discussion about how to handle next hops and forwarding information within BGP updates.

Key Discussion Points

BGP-LS Extensions for T-Policy Advertisement: Discussions centered on splitting the existing draft into two parts, focusing specifically on the SR policy part due to existing implementations. The need for implementations of RSVP-TE and static cross-connect types was emphasized.
BGP YANG Model: Updates included transport security enhancements and collaboration with the TCP Yang model authors. The remaining major work item is modeling regular expressions against AS paths, which will be addressed in a side meeting. Deep scrutiny is requested for the module, particularly for VPN and extended community modeling.
Deprecation of AS Sets: The primary goal is to improve BGP security by discouraging the use of AS sets, which cause ambiguity in route origin validation. The recommendation is to treat AS set withdrawals as withdrawals and to avoid creating new AS sets. Clarification of the term "obsoleting" was also requested, given the existing backwards compatibility requirements.
BGP Extensions for Service Metadata: A new draft proposes a new attribute to propagate service metadata of attached sites to impact the BGP decision, and a name change to differentiate the next hop was brought up.
BGP-LS Policy Extensions for IGP Metric: The proposal involves adding a metric sub-TLV to BGP-LS policies to allow routers to choose the next hop based on IGP metrics. Discussion focused on the placement of the metric at the candidate path level versus the segment list level.
IPv4 Islands over IPv6 Core (4PE): The draft proposes a solution for connecting IPv4 islands over an IPv6 core, mirroring the existing 6PE architecture. It also discussed extending it to segment routing with mpls and srv6.
Risks of Redirection Mechanisms: The discussion highlighted potential risks associated with traffic redirection mechanisms like BGP flow spec, including traffic detours, black holes, and loops. Participants suggested this could be better addressed in the GROW working group. The concern about misuse of flowspec was also raised.
BGP Flow Spec for ITM Network Slice Traffic Steering: The draft extends BGP flow spec to steer network slice traffic into specific network resource pools (NRPs).
BGP Extension for Micro-banding: The draft proposes distributing bonding information to adjacent nodes to enable fast reroute in case of node failure.
Extending Route Target Extended Community: A proposal to derive an extended community from a route target with a new subtype.
Multinational Next Hop Attribute: A comprehensive proposal for unifying how next hops and forwarding information are carried in BGP. It allows for multiple next hops, various forwarding actions, and scoping controls. This elicited concerns regarding increased complexity.

Decisions and Action Items

BGP-LS Extensions for T-Policy Advertisement: Ketan will prepare a split version of the document for review.
BGP YANG Model: The authors will hold a side meeting to discuss modeling regular expressions against AS paths.
Deprecation of AS Sets: The document will be refined to clarify the language around obsoleting AS sets, incorporate feedback on forwarding loops, and add a button to easily reject AS set routes.
Risks of Redirection Mechanisms: The authors were encouraged to present their work to the GROW working group.
BGP Flow Spec for ITM Network Slice Traffic Steering: Authors will revise the document.

Next Steps

Authors to revise and resubmit drafts based on feedback.
Further discussion on the mailing lists, especially regarding the multinational next hop attribute.
Consideration of adoption for several drafts.