Re: [sfc] The SFC WG has placed draft-wang-sfc-multi-layer-oam in state "Candidate for WG Adoption"

Joel and Jim,

Please find some comments and questions on this document, for the authors and WG consideration — this note neither supports nor opposes adoption. Apologies for the late email.

3.  Requirements for Active OAM in SFC Network
…
      REQ#3: SFC OAM MUST support Remote Defect Indication (RDI)
      notification by the egress to the ingress.
…
      REQ#7: SFC OAM MUST have the ability to discover and exercise all
      available RSPs in the transport network.

CMP: This document includes a list of Requirements. It is somewhat elusive why some and not others. It is unclear the reason why it lists requirements for Active OAM only instead of Requirements for operations and manageability of SFCs — the former focuses on a solution in mind, the latter focuses on the larger problem space.

4.  Active OAM Identification in SFC NSH

   The interpretation of O bit flag in the NSH header is defined in
   [RFC8300] as:

      O bit: Setting this bit indicates an OAM packet.

   This document updates the definition of O bit as follows:

      O bit: Setting this bit indicates an OAM command and/or data in
      the NSH Context Header or packet payload

CMP: I oppose this update. If the O bit is Set, that will trigger a processing exception. That should not have user Data at all.

CMP: Additionally, Section 4 says:

   Active SFC OAM defined as a combination of OAM commands and/or data
   included in a message that immediately follows the NSH.  To identify

CMP: Section 1 says:

   This document defines how active Operation, Administration and
   Maintenance (OAM), per [RFC7799] definition of active OAM, identified

CMP: But RFC 7799 says nothing about a command or data.

5.  Echo Request/Echo Reply for SFC in Networks

CMP: What specifically is the need to invent a new protocol as opposed to, for example, use ICMP Echo / Reply? 

Thanks!

—
Carlos Pignataro, carlos@cisco.com <mailto:carlos@cisco.com>

"올려다 봐 이렇게 마주한 같은 하늘”
“Look up, we're all looking at the same sky."
-Kim NamJoon

> On Oct 8, 2018, at 6:20 PM, IETF Secretariat <ietf-secretariat-reply@ietf.org <mailto:ietf-secretariat-reply@ietf.org>> wrote:
> 
> 
> The SFC WG has placed draft-wang-sfc-multi-layer-oam in state
> Candidate for WG Adoption (entered by Joel Halpern)
> 
> The document is available at
> https://datatracker.ietf.org/doc/draft-wang-sfc-multi-layer-oam/ <https://datatracker.ietf.org/doc/draft-wang-sfc-multi-layer-oam/>
> 
> Comment:
> This document has been presented at several SFC working group sessions.  The
> authors have asked for Working Group Adoption.  This starts a two week call
> for that adoption.  Please speak up, preferably with supporting explanations,
> in favor of or opposed to the working group adopting this document. The last
> call will end CoB  somewhere 22-October-2018 (e.g. by the time I do anything
> about it, it will be at least the 23rd everywhere.)
> 
> Thank you,
> Joel and Jim
> 
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