Re: [sfc] Use of Alternate Marking Method in SFC

[Dave Dolson <[e-mail]>]

(Adding sfc list)
Thanks Greg. I see I reviewed an older document by mistake.
I still feel that the brief theory of operation does a disservice to the document by raising questions, whereas the ippm-alt-mark is much more nuanced and complete.
Having said that, you could pre-amble the theory of operation with, “The following is an over-simplified description for the sake of providing context…”

-Dave


From: Greg Mirsky [mailto:[e-mail]]
Sent: Tuesday, July 4, 2017 7:13 PM
To: Dave Dolson
Subject: Re: [sfc] Use of Alternate Marking Method in SFC

Hi Dave,
many thanks for your interest in this draft and the most helpful comments. I agree that given progress of the Alternate Marking draft at IPPM WG there's no apparent reason to replicate much information in this document (engineers are expected to be able to follow references and links). Couple notes in-line and tagged GIM>>.

Regards,
Greg

On Tue, Jul 4, 2017 at 8:53 AM, Dave Dolson <[e-mail]<mailto:[e-mail]>> wrote:
Greg,
Given that this document doesn’t explain everything—certainly not enough to implement it—consider making this document very simple, and refer to the draft-ietf-ippm-alt-mark for details.
E.g., this document should just contain:
- which NSH bits are used for Single and Double
GIM>> With -01 version that is more specific on Mark field allocation and bit position designation and use.
- which SFC functions are permitted to write the marks (I think just the classifier, but I don’t think you even say this)
GIM>> Very helpful, thank you! Indeed, the Classifier is the most logical function to perform marking for SFC. Though I'd consider making it as strong recommendation thus allowing marking by other functions.
- where should measurements be taken.
GIM>> Measurements may be taken anywhere along the SFP and without any restrictions to packet size, as measurement results been stored locally and may be exported by out-band transport, e.g. YANG notifications (Netconf or Rest), IPFIX, gRPC. That, in my opinion, is advantage of the AM method when compared to, for example, iOAM.

In other words, I suggest removing any intent to describe the theory of operation or algorithm, when draft-ietf-ippm-alt-mark explains it all.

-Dave


From: sfc [mailto:[e-mail]<mailto:[e-mail]>] On Behalf Of Greg Mirsky
Sent: Wednesday, June 14, 2017 10:54 AM
To: [e-mail]<mailto:[e-mail]>
Cc: Fioccola Giuseppe ([e-mail]<mailto:[e-mail]>)
Subject: [sfc] Use of Alternate Marking Method in SFC

Dear All,
would like to bring your attention to the draft  Performance Measurement (PM) with Alternate Marking Method in Service <https://tools.ietf.org/html/draft-mirsky-sfc-pmamm-00>
Function Chaining (SFC) Domain<https://tools.ietf.org/html/draft-mirsky-sfc-pmamm-00>
we've submitted earlier. Alternate Marking method allows performance measurement performed close to passive measurement methods.
Greatly appreciate your questions, comments, and suggestions.

Regards,
Greg