Re: [Idr] Color & TC semantics (was Re: I-D Action: draft-ietf-idr-bgp-ct-30.txt )

[Ketan Talaulikar <[e-mail]>]

A gentle reminder on this one please ...


On Mon, Mar 18, 2024 at 6:00 PM Ketan Talaulikar <[e-mail]>
wrote:

> Hi Kaliraj/Nats,
>
> I have one concern about this change introduced in the latest version of
> the document.
>
> https://www.ietf.org/archive/id/draft-ietf-idr-bgp-ct-30.html#section-13.4
>
> As noted in Sec 4 and Sec 7.10, 'Transport Class ID' is interchangeable
> with 'Color'. *For purposes of backward compatibility with usage of
> 'Color' field in Color extended community, the range 1-4294967295 uses
> 'Private Use'* as Registration Procedure.
>
> Per RFC9012, there is no special semantics associated with the color value
> 0. The CT draft has introduced special semantics for TC ID 0 (this is not
> an issue) but seems to be associating those semantics to Color as well. Can
> you please clarify the intent here?
>
> If you remember, I had this concern with the introduction of a new term TC
> for something that seems the same as Color.
>
> I had also suggested to simply do away with the IANA registration for TC -
> ID and just specify in the spec the special semantics of zero TC-ID. Doing
> IANA registration for TC-ID this way is quite pointless. We have several
> instances in routing protocols where we define protocol constant/special
> values [1].
>
> Thanks,
> Ketan
>
> [1] An example from top of my mind is in ISIS
> https://datatracker.ietf.org/doc/html/rfc5305#section-3 where
> MAX_PATH_METRIC is defined or OSPF RFC2328 where LSInfinity is defined
> without the need for an IANA registration.
>
>
> On Mon, Mar 18, 2024 at 9:42 AM <[e-mail]> wrote:
>
>> Internet-Draft draft-ietf-idr-bgp-ct-30.txt is now available. It is a work
>> item of the Inter-Domain Routing (IDR) WG of the IETF.
>>
>>    Title:   BGP Classful Transport Planes
>>    Authors: Kaliraj Vairavakkalai
>>             Natrajan Venkataraman
>>    Name:    draft-ietf-idr-bgp-ct-30.txt
>>    Pages:   75
>>    Dates:   2024-03-17
>>
>> Abstract:
>>
>>    This document specifies a mechanism referred to as "Intent Driven
>>    Service Mapping".  The mechanism uses BGP to express intent based
>>    association of overlay routes with underlay routes having specific
>>    Traffic Engineering (TE) characteristics satisfying a certain Service
>>    Level Agreement (SLA).  This is achieved by defining new constructs
>>    to group underlay routes with sufficiently similar TE characteristics
>>    into identifiable classes (called "Transport Classes"), that overlay
>>    routes use as an ordered set to resolve reachability (Resolution
>>    Schemes) towards service endpoints.  These constructs can be used,
>>    for example, to realize the "IETF Network Slice" defined in TEAS
>>    Network Slices framework.
>>
>>    Additionally, this document specifies protocol procedures for BGP
>>    that enable dissemination of service mapping information in a network
>>    that may span multiple cooperating administrative domains.  These
>>    domains may be administered either by the same provider or by closely
>>    coordinating providers.  A new BGP address family that leverages RFC
>>    4364 procedures and follows RFC 8277 NLRI encoding is defined to
>>    advertise underlay routes with its identified class.  This new
>>    address family is called "BGP Classful Transport", a.k.a., BGP CT.
>>
>> The IETF datatracker status page for this Internet-Draft is:
>> https://datatracker.ietf.org/doc/draft-ietf-idr-bgp-ct/
>>
>> There is also an HTMLized version available at:
>> https://datatracker.ietf.org/doc/html/draft-ietf-idr-bgp-ct-30
>>
>> A diff from the previous version is available at:
>> https://author-tools.ietf.org/iddiff?url2=draft-ietf-idr-bgp-ct-30
>>
>> Internet-Drafts are also available by rsync at:
>> rsync.ietf.org::internet-drafts
>>
>>
>> _______________________________________________
>> Idr mailing list
>> [e-mail]
>> https://www.ietf.org/mailman/listinfo/idr
>>
> _______________________________________________
> Idr mailing list
> [e-mail]
> https://www.ietf.org/mailman/listinfo/idr
>