[Idr] IETF 117 - IDR Chair slides: CAR, Question-2

[Kaliraj Vairavakkalai <[e-mail]>]

Hi Sue, IDR-Chairs,

Quick response to Question 2 on IDR Chair slides, Page 4:

https://datatracker.ietf.org/meeting/117/materials/slides-117-idr-sessa-01-chairs-introduction-slides-to-carct


·         CAR

o   Question-2: Do new sections need more review?


Yes. The new sections need more review. They don’t have an implementation either.

Actually following items have “no implementation” as-per the implementation report<https://wiki.ietf.org/group/idr/implementations/draft-ietf-idr-bgp-car>:

  *   LCM EC
  *   Type 2 NLRI
  *   VPN CAR (Type 1 or Type 2)

This list includes items which are new in car-02 and also some existing items in car-01.

Implementation experience may show us that some changes may be required in procedures.

Most procedures present in the draft are for CAR SAFI Type 1 NLRI (E,C), where Color is in NLRI.

(e.g. 2.1<https://datatracker.ietf.org/doc/html/draft-ietf-idr-bgp-car-02#section-2.1>.  Data Model, section 3<https://datatracker.ietf.org/doc/html/draft-ietf-idr-bgp-car-02#section-3> Service route Automated Steering on Color-Aware path)



Procedures are missing for the other NLRI types (VPN-CAR and Type 2 NLRI).

Procedures are missing on how the different route types and SAFIs interoperate with each other:

  *   Type 1 CAR
  *   Type 1 VPN-CAR
  *   Type 2 CAR
  *   Type 2 VPN-CAR
As all of these route-types intend to provide solution to the same problem of “end-to-end intent-aware paths”,
some customers may choose one NLRI variant and some others may chose a different one. How do they work together?

For VPN-CAR (Sec 8 and Sec 10.2), Procedures are missing on

  *   How RD and RT usage happens in transport layer.
  *   How collision with RT used at Service layer (e.g. SAFI 128) is handled.
  *   How BNs work for VPN-CAR. See Topology in Sec 8<https://datatracker.ietf.org/doc/html/draft-ietf-idr-bgp-car-02#section-8>, it has no BNs. Only ingress and egress PEs.
  *   Interaction between service-families and vpn-car routes.

We will try to send more comments on review of the draft text. But time is of essence.

As noted by Susan, it can be seen the solution is still evolving as new types are being added for scenarios that
have been in discussion since 2021, and they lack implementation.

I hope other WG memebers (specifically who are ‘supporters of CAR’) are reviewing the draft to
ensure it is correct, complete and solves their problems.

Thanks,
Kaliraj


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