Re: [Idr] Opsdir early review of draft-ietf-idr-bgp-ct-19

[Kaliraj Vairavakkalai <[e-mail]>]

Hi Bo Wu,

Thanks for further comments. Please see inline. KV>

I have made some updates accordingly in draft version -20.

https://datatracker.ietf.org/doc/html/draft-ietf-idr-bgp-ct-20

Please take a look and let me know if you have any further comments.

Thanks,
Kaliraj



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From: Bo Wu via Datatracker <[e-mail]>
Date: Friday, January 5, 2024 at 1:20 AM
To: [e-mail] <[e-mail]>
Cc: [e-mail] <[e-mail]>, [e-mail] <[e-mail]>
Subject: Opsdir early review of draft-ietf-idr-bgp-ct-19
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Reviewer: Bo Wu
Review result: Has Nits

Hi,

I am the assigned Ops reviewer to conduct the "early" review of this draft.
This is my second review.

Thanks for addressing my previous comments. I have few minor comments on rev-19:

1)Abstract and Section 3. Architecture Overview
Abstract says “overlay routes”, but section 3 uses “service routes”. Can the
service route be used consistently? If not, can you add the difference?

KV> overlay routes can be either service-routes (e.g., SAFI 1 or SAFI 128) or transport-routes (SAFI 4 or SAFI 76).
KV> underlay routes can be either the intra-domain tunnels (e.g., RSVP-TE, SRTE) or BGP transport-routes (SAFI 4 or SAFI 76).
KV> So where ever we want to specifcally mention service routes, there we don’t use ‘overlay’. But if we want to generally talk about the ‘resolving route’, then we use the term ‘ovelay’.

2) 3. Architecture Overview
Please add the description or examples of SN for Figure 1.

KV> PE21, SN11 and PE11 are the SNs. Added a line clarifying this.

3) 4. Transport Class
The document says "The terms'Transport Class ID' and'Color' are used
interchangeably in this document"

These two seem two different definitions, as section 7.10. has the following
text: "Transport Class ID SubTLV, in MultiNexthop Attribute. Color SubTLV, in
Tunnel Encapsulation Attribute. Transport Target Extended community, on BGP CT
route. Color Extended community, on BGP service route."

KV> all of these carry a 32-bit value which is called the ‘Color’ or ‘Transport Class ID’
KV> So, the Color/TC-ID extracted from these attributes is comparable, is the same thing.

4) 10. Operations and Manageability Considerations
Only RDs and labels are discussed. Should transport class RT managment also be
described in this section?

KV> Transport Class RT management is discussed else where, e.g., in Sec 4.3, 11.1, 11.2

5) 12. Applicability to Network Slicing
Network slice is just an example of BGP CT. Should this section be an appendix?
KV> It is one of the important use-cases. So prefer to keep this small section in main text.

About Mapping Community, Network Slice service traffic mapping occurs on the
PE's CE-facing interfaces, while Mapping community is on the PE's
network-facing interfaces, correct?

KV> Mapping-community can be attached at the egress-PE or CE attached to it.
KV> It is used by the Ingress-PE to resolve service-route over the right Transport-class tunnel, on core-facing interfaces.
KV> This is explained in Sec 7.8. Thanks.