Session Date/Time: 23 Oct 2023 14:00

IDR

Summary

The IDR Working Group interim meeting focused on status updates for the BGP Color-Aware Routing (CAR) and BGP Color-Aware Transit (CT) drafts, which are both progressing towards experimental RFC publication. A significant discussion took place regarding the future direction for intent-aware routing, where the chair indicated a strong sense from the working group to eventually base proposed standard work on the CAR draft after both CAR and CT are published as experimental. The meeting also included brief presentations on two informational drafts, "BGP Colored Prefix Routing for SRv6 Based Services" (draft-wang-idr-cpr) and "IPv4 Islands over IPv6 Core (4PE)" (draft-mishra-idr-v4-island-64-core), both of which are currently in or nearing adoption calls. Several other adoption calls were announced for review.

Key Discussion Points

BGP Color-Aware Routing (CAR) Draft Status:
- The authors are in the process of updating the draft to address issues identified during the last working group last call (WGLC), including clarifying Type 1 vs. Type 2 routes and reorganizing the draft for better flow.
- Comments from Jeff were addressed privately and will be posted to the IDR mailing list.
- The draft is being prepared for publication as an experimental RFC.
BGP Color-Aware Transit (CT) Draft Status:
- Draft -17 has been published with fixes and is ready for a second WGLC.
- Key changes in -17 include:
  - Clarification on receive-side handling of reserved bits (ignored on reception, must be left unaltered).
  - Removal of normative references to individual drafts by moving procedures into their respective documents or new drafts, now using informational references only.
  - Added clarifying text and fixed errors in tables related to route scale and label changes, addressing swadesh's previous comments.
- All 25 GitHub issues for CT are now closed.
- Routing, OBS, and Security directorate reviews are pending.
Future Direction for Intent-Aware Routing (CAR vs. CT):
- The chair stated the intent to publish both CAR and CT as experimental RFCs.
- Following their experimental publication, the working group's sense indicates that the CAR draft will be used as the basis for future proposed standard work on intent-aware routing.
- K Raj expressed concern about selecting a proposed standard candidate at this stage, advocating for feedback from experimental implementations first, and highlighting CT's completeness and deployment status.
- The chair clarified that this is an indication of direction based on current working group consensus to allow planning, not a final decision on a proposed standard. The process for moving from experimental to proposed standard will involve a new adoption call for the selected draft.
Ongoing Adoption Calls:
- Three drafts are currently open for adoption calls and review: draft-zang-idr-policy-segment-list, draft-liu-idr-policy-seg-list, and draft-sangle-idr-bgp-generic-metric-aigp. These are expected to close by the next IDR meeting.
BGP Colored Prefix Routing for SRv6 (draft-wang-idr-cpr) Presentation:
- G presented an informational draft proposing a mechanism for inter-domain intent-aware paths for SRv6 services.
- It reuses existing BGP technologies, IPv6 unicast address family, and the color extended community.
- Key updates include a terminology change from "colorful" to "colored" prefix routing, further clarification on existing technologies, and simplified examples.
- An adoption call for this draft has recently started.
- K Raj raised a concern about using IPv6 unicast as a transport family, suggesting it's not a good idea for carrying service routes without proper isolation. G noted this is a recognized trade-off for operators, with options for addressing it.
IPv4 Islands over IPv6 Core (4PE) (draft-mishra-idr-v4-island-64-core) Presentation:
- G presented an informational document describing how to connect IPv4 islands over an IPv6 core using BGP.
- The draft has been changed from Standards Track to Informational.
- It outlines flexibility beyond its predecessor (6PE), allowing for unlabeled IPv4 prefixes and various use cases, supporting different label allocation modes (per prefix, per VRF, per CE).
- K Raj questioned the use of Safi 4 for carrying service routes and how labels are signaled if Safi 4 is not used consistently, emphasizing the need for a uniform approach. G and K Raj were encouraged to continue this technical discussion on the mailing list.

Decisions and Action Items

Decision: The IDR WG intends to publish both the CAR and CT drafts as experimental RFCs.
Decision: After experimental publication, the CAR draft is currently the indicated basis for future proposed standard work on intent-aware routing, pending a new adoption call at that stage.
Action Item: DJ (CAR author) to post the responses to Jeff's comments regarding CAR to the IDR mailing list.
Action Item: Swadesh to review CT draft -17 and send suggestions for improvements to the list, focusing on his remaining open issue.
Action Item: Chair to send out a reference to the previous mailing list discussion and/or a new note clarifying the procedural aspects of the IDR WG's stated direction for intent-aware routing (experimental for CAR/CT, CAR as basis for future proposed standard work).
Action Item: Med and Boventu are requested to complete their Routing Directorate and OBS Directorate reviews for the CT draft.
Action Item: K Raj and G (on draft-wang-idr-cpr) to continue their discussion on using IPv6 unicast as a transport family for service routes on the IDR mailing list.
Action Item: K Raj and G (on draft-mishra-idr-v4-island-64-core) to continue their discussion on the consistent handling of Safi 4 and label signaling for service routes on the IDR mailing list.

Next Steps

CAR & CT Drafts: Continue preparing both drafts for publication as experimental RFCs. The CT draft will proceed to a second working group last call after swadesh's review is addressed.
Adoption Calls: Working group participants are encouraged to review and comment on the three active adoption calls (draft-zang-idr-policy-segment-list, draft-liu-idr-policy-seg-list, and draft-sangle-idr-bgp-generic-metric-aigp) as they are expected to close soon.
Informational Drafts: The adoption call for draft-wang-idr-cpr is active, and an adoption call for draft-mishra-idr-v4-island-64-core is expected to start soon. Reviews and comments on the mailing list are encouraged.
Future IDR Sessions: Participants interested in presenting at future IDR sessions should submit requests to the secretary.