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

Ketan:

My understanding was that

  1.  TC-id = 0 was only defined for transport class ID,
  2.  Configuration of the transfer between color and transport class ID was an implementation specific “knob”.

I could be wrong.  Kaliraj responds really quickly if he can.  I suspect he’ll respond to us by Monday or Tuesday.

Cheers, Sue

PS – Warning – in 8 hours I start my trip back home.  I’ll try to respond from airport, but you know how travel is.

From: Ketan Talaulikar <ketant.ietf@gmail.com>
Sent: Friday, March 22, 2024 4:49 AM
To: Susan Hares <shares@ndzh.com>
Cc: Kaliraj Vairavakkalai <kaliraj@juniper.net>; natv@juniper.net; idr@ietf. org <idr@ietf.org>
Subject: Re: [Idr] Color & TC semantics (was Re: I-D Action: draft-ietf-idr-bgp-ct-30.txt )

Hi Sue, I don't mind if the registry is retained. Not using the registry was a solution - not the issue. My concern was: https://www.ietf.org/archive/id/draft-ietf-idr-bgp-ct-30.html#section-13.4 As n
External (ketant.ietf@gmail.com<mailto:ketant.ietf@gmail.com>)
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Hi Sue,

I don't mind if the registry is retained. Not using the registry was a solution - not the issue.

My concern was:
https://www.ietf.org/archive/id/draft-ietf-idr-bgp-ct-30.html#section-13.4<https://shared.outlook.inky.com/link?domain=www.ietf.org&t=h.eJxFzk0OgyAYRdGtGDot_1LUkVtBQCEqGvxakzbde0snnb6bnLwXuucFdRUKAPvRUXqeJ4keRrLliZpsQ3x4Gh112YyAS8HRZTxMO7aAJSMB1uVyeAtxS5hLUqNrheZCJg9fhDPV3Fou6BFM9kef3DMQu630pljN28YNrWbaCSYEG5SR2oxqtEJbyjXnrNVS1UTIovqizh5Mgt_HflpNXApWqiv1v7w_9bVDAA.MEUCIQCFLdwLI5bq3SANh79XwcRU030Qy7GjGvSl8_0jo9xCLgIgNChbGJpIWs6KWZqt2vqJj4Mh666ziKbJwInMtkQ0oEQ>

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?

I hope this document is not trying to change the semantics of the color value "0" in the Color extended community.

Thanks,
Ketan

On Fri, Mar 22, 2024 at 2:11 PM Susan Hares <shares@ndzh.com<mailto:shares@ndzh.com>> wrote:
Ketan and Kaliraj:

Ketan thanks for mentioning this point.

On the following comment from Ketan:

“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].”

IANA has checked Kaliraj’s usage of the registry.  As it stands, Ketan’s was the only comment on this matter of registry during the WG LC.  I had a long chat with Kaliraj at IETF-119 about the pros/cons of the registry.  He’s aware of all the choices of assignment.

[Shepherd’s hat on]
My current plan is to note this issue in my shepherd’s report.  I will ask if the IESG has a strong preference.  If the IESG has a strong opinion, I’m sure John Scudder will help me adjust it.

At this point, I do not see any profit in holding up sending the document to the IESG.
[Shepherd]s hat off]

Let me know what you think about this approach.

Sue

From: Ketan Talaulikar <ketant.ietf@gmail.com<mailto:ketant.ietf@gmail.com>>
Sent: Thursday, March 21, 2024 11:05 PM
To: Kaliraj Vairavakkalai <kaliraj@juniper.net<mailto:kaliraj@juniper.net>>; natv@juniper.net<mailto:natv@juniper.net>
Cc: idr@ietf. org <idr@ietf.org<mailto:idr@ietf.org>>; Susan Hares <shares@ndzh.com<mailto:shares@ndzh.com>>
Subject: Re: [Idr] Color & TC semantics (was Re: I-D Action: draft-ietf-idr-bgp-ct-30.txt )

A gentle reminder on this one please ...

On Mon, Mar 18, 2024 at 6:00 PM Ketan Talaulikar <ketant.ietf@gmail.com<mailto:ketant.ietf@gmail.com>> 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<https://shared.outlook.inky.com/link?domain=www.ietf.org&t=h.eJxFzk0OgyAYRdGtGDot_1LUkVtBQCEqGvxakzbde0snnb6bnLwXuucFdRUKAPvRUXqeJ4keRrLliZpsQ3x4Gh112YyAS8HRZTxMO7aAJSMB1uVyeAtxS5hLUqNrheZCJg9fhDPV3Fou6BFM9kef3DMQu630pljN28YNrWbaCSYEG5SR2oxqtEJbyjXnrNVS1UTIovqizh5Mgt_HflpNXApWqiv1v7w_9bVDAA.MEUCIQCFLdwLI5bq3SANh79XwcRU030Qy7GjGvSl8_0jo9xCLgIgNChbGJpIWs6KWZqt2vqJj4Mh666ziKbJwInMtkQ0oEQ>

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<https://shared.outlook.inky.com/link?domain=datatracker.ietf.org&t=h.eJxFjkkSwiAURK9i4VYZQwhZ5SqEIaSSgAXfjZZ3V7Jx26_7Vb_Rs-xovKAI8KgjIc6AgWLs5gtePQScy0JctiTCsZMSrBRUXqu3sOZ0F-h2QVvbJw-_JqNy6DXjpEZTfJ2Se0Vs80F6STumBzdrRZXjlHM6SyOUCTJYrixhijGqlZAd5qfVN-vmwSQ4j0zLYda9yRp1jf6TzxeorDyj.MEYCIQDapQUeEaYVAj5h5TS2Ib2CXKPOhqtOZ0_JzLbGCmkQewIhALbSYnZkjmyIG6T6dXN5wGdum-EwuEbUy3QOFm-5Mga2> 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 <internet-drafts@ietf.org<mailto:internet-drafts@ietf.org>> 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/<https://shared.outlook.inky.com/link?domain=datatracker.ietf.org&t=h.eJxFjjsOgzAQRK8SuY6_YIypuMritQHxldk0iXL3xGnSzpt5mhd75JV1NzYRnVcnJQIBZQhLzGKOlMSRR4lHkJghES8RnzHzYTx5IMnuN7aU_R7p29TKto3XRl4T5Hj1Oz4nEY5NNlbV2rc4eKccGmWMGixUDpJNwbggtdNaeVfZWpiqWGOxLpFgp9-RftxgXousUCz0n7w_9yQ9Kg.MEUCIEUDH70OFPti7HFci1fYbKSb1AdFq4FuyLS_3itU8yURAiEA8MRpzqrQuZTJavfzMYIdiGA7dJ9podTih50FXNSxVjc>

There is also an HTMLized version available at:
https://datatracker.ietf.org/doc/html/draft-ietf-idr-bgp-ct-30<https://shared.outlook.inky.com/link?domain=datatracker.ietf.org&t=h.eJxFjjkOgzAUBa8SuY53jDEVV_l4wYhV5qdJlLsnTpN2Rm_0XuRRVtLfSEY8r57zAAhYwC-xsDliYkeZeDg8z7itPBRISCuncyh0nE7qkWpB7jey1Mwe8TuQwnStk4pfGUq8hj08M_PHxlsjGum6MDorbFBCKTEa0BaSSV5Zz6WVUjirTcOUrtVYq0tE2PH3Z5g2mNcaqzZU-yfvD9cWP28.MEUCIHiTSkY1XmerVxvVBlrZCbYTFt9B1LphHw-KM40Z0H-KAiEA_77puACeNLHMdYvZN2c2gXaQK8FMB8m8OsRrbWu7LJA>

A diff from the previous version is available at:
https://author-tools.ietf.org/iddiff?url2=draft-ietf-idr-bgp-ct-30<https://shared.outlook.inky.com/link?domain=author-tools.ietf.org&t=h.eJxFjssOgyAURH-lYV3kJSImTf0V5KHEBwavmzb990o33c6ZOZk3OvOCuhuaAPajI8ScMKWMIaXlqKKHUKU8kuhcDOF5dfnDZRMAF4Sjy3gYd2wBC4ruNzQX1ebh2jAq20YzTo7JZH_0m3tNlU0raSStmW7doBVVjlPO6SCNUCbIYLmyhCnGqFZC1hUXxeqLdfZgNvhd6sfVxKXICnWF_pPPFxXCQPg.MEUCIHZnHY3nB7SHu8ZG1r901OEG-5Ffsb1pTSVr7VZogVseAiEAvq2QpZ9F93gmUeTRL2QEMswkCCLIMgzD8jOWjmIChTU>

Internet-Drafts are also available by rsync at:
rsync.ietf.org<https://shared.outlook.inky.com/link?domain=rsync.ietf.org&t=h.eJxFjcsOgyAUBX_FsG7gAiLiyl9BHmpUNHC7aJv-e0s3XZ6ZZM6L3PNOhoYsiNfAWC6P5OgaMNIzz-TWkK3aFPA7Oai-M1ywstgcypj8c6HuPFinoOWm95PRoL0AIWBSVmobVXRCO8Y152C0VC0VslZDrW4BbcLf2zgfdt1rrFpf7Z-8PzCIMOE.MEUCIGTayiqRlJRq7FWEmcPKpWVovLLRev8IUWk-JO3ARh8LAiEAz2BnWY8rN5bvFF_QXrzCm_f-4RYBKxFfqd0xzizpP1M>::internet-drafts

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