Re: [ippm] New Version Notification for draft-filsfils-spring-path-tracing-00.txt

["Ahmed Abdelsalam (ahabdels)" <[e-mail]>]

Hi Andrew,

Thanks for the review and comments. Please find Inline [AA]

From: ippm <[e-mail]> on behalf of Andrew Alston - IETF <andrew-ietf=[e-mail]>
Date: Monday, 14 March 2022 at 16:08
To: Ahmed Abdelsalam (ahabdels) <ahabdels=[e-mail]>, [e-mail] <[e-mail]>, [e-mail] <[e-mail]>, [e-mail] <[e-mail]>
Subject: Re: [ippm] New Version Notification for draft-filsfils-spring-path-tracing-00.txt
Hi There,

Speaking entirely as a working group participant,

I have two substantial concerns with this document at first skim read.

Firstly – the 12 bits for an interface ID – I have serious concerns that this will be far from sufficient.  Keep in mind you have interface specific VLAN’s (that alone can eat 12 bits), you have PWHE terminated interfaces – and I know of several cases where those are used for termination of logical circuits that would be doing this type of traffic, etc etc, and in effect, you can very easily exceed the 4096 interface ID’s on a single router.

[AA] As mentioned in the draft. The interface ID is assigned by an operator. It does not have to be either globally unique across the entire network, or even unique withing the node as long as the end-to-end path can be deterministically inferred based on the chain of Interface IDs.

Secondly, in the security considerations section of the document, last paragraph of section 11.  It states “The HBH-PT option MUST be processed at line rate.” I think the wording here probably needs work.  Could we not say that “A router that cannot process the HBH-PT option in fast path must ignore said option” Because “line rate” does not actually refer to packets that avoid punt to the CPU – all it means is that the CPU’s are fast enough to not slow other things down while processing it.

[AA] The intent is to avoid any slowdown in forwarding. draft-ietf-6man-hbh-processing uses slow-path and fast-path language and may provide better language to describe the requirement for HBH-PT option.  We’ll update that in the next version.

Thanks!

Thanks
Andrew

From: spring <[e-mail]> On Behalf Of Ahmed Abdelsalam (ahabdels)
Sent: Wednesday, March 9, 2022 5:13 PM
To: [e-mail]; [e-mail]; [e-mail]
Subject: [spring] FW: New Version Notification for draft-filsfils-spring-path-tracing-00.txt

Dear SPRING WG,  IPPM WG,

We have submitted a new I-D for Path Tracing in SRv6 networks (https://datatracker.ietf.org/doc/html/draft-filsfils-spring-path-tracing) to SPRING WG.

We are looking for your feedback and comments.

Path Tracing provides a record of the packet path as a sequence of interface ids. In addition, it provides a record of end-to-end delay, per-hop delay, and load on each egress interface along the packet delivery path to facilitate operation of SR networks.

Path Tracing allows to trace 14 hops with only a 40-octet IPv6 Hop-by-Hop extension header.

We will present Path Tracing to the SPRING WG at next IETF (https://datatracker.ietf.org/meeting/113/materials/agenda-113-spring-00.txt)

Thanks,
Ahmed

From: [e-mail] <[e-mail]>
Date: Friday, 4 March 2022 at 16:48
To: Ahmed Abdelsalam (ahabdels) <[e-mail]>, cf(mailer list) <[e-mail]>, Mark Yufit <[e-mail]>, Pablo Camarillo (pcamaril) <[e-mail]>, Pablo Camarillo (pcamaril) <[e-mail]>, Satoru Matsushima <[e-mail]>, Thomas.Graf <[e-mail]>, Yuanchao Su <[e-mail]>
Subject: New Version Notification for draft-filsfils-spring-path-tracing-00.txt

A new version of I-D, draft-filsfils-spring-path-tracing-00.txt
has been successfully submitted by Pablo Camarillo Garvia and posted to the
IETF repository.

Name:           draft-filsfils-spring-path-tracing
Revision:       00
Title:          Path Tracing in SRv6 networks
Document date:  2022-03-04
Group:          Individual Submission
Pages:          15
URL:            https://www.ietf.org/archive/id/draft-filsfils-spring-path-tracing-00.txt
Status:         https://datatracker.ietf.org/doc/draft-filsfils-spring-path-tracing/
Htmlized:       https://datatracker.ietf.org/doc/html/draft-filsfils-spring-path-tracing


Abstract:
   Path Tracing provides a record of the packet path as a sequence of
   interface ids.  In addition, it provides a record of end-to-end
   delay, per-hop delay, and load on each egress interface along the
   packet delivery path.

   Path Tracing allows to trace 14 hops with only a 40-bytes IPv6 Hop-
   by-Hop extension header.

   Path Tracing supports fine grained timestamp.  It has been designed
   for linerate hardware implementation in the base pipeline.




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