Subject: [sfc] Benoit Claise's No Objection on draft-ietf-sfc-nsh-25: (with COMMENT)

From: Benoit Claise <[email-masked]>
Date: Thu, 28 Sep 2017 06:55:45 -0700

Benoit Claise has entered the following ballot position for
draft-ietf-sfc-nsh-25: No Objection

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----------------------------------------------------------------------
COMMENT:
----------------------------------------------------------------------

- Section 2.5.1., you might want to mention that no metadata are specified at
this point in time. Indeed, "New IETF Assigned Optional Variable Length
Metadata Type Registry is specified in this doc., but empty

- Section 2.3
OPS question: SPI must be unique per admin domain? Otherwise, you're looking
for trouble, right? This would be typically addressed in an "Operational
Considerations" section. Where is my "Operational Considerations" section...?

- Section 2.4
Fixed length metadata.

   This specification does not make any assumptions about the content of
   the 16 byte Context Header that must be present when the MD Type
   field is set to 1, and does not describe the structure or meaning of
   the included metadata.

   An SFC-aware SF MUST receive the data semantics first in order to
   process the data placed in the mandatory context field.  The data
   semantics include both the allocation schema and the meaning of the
   included data.

I understand that the order of the metadata in the Fixed Length Context Header
is important, right? Should it be mentioned? I understand that the fixed length
metadata are specific per service, and that's the reason why there is no IANA
for fixed length. Should this be mentioned?

- if you publish a new version, change the order of these two paragraphs:

   Unassigned bits: All other flag fields, marked U, are unassigned and
   available for future use, see Section 11.2.1.  Unassigned bits MUST
   be set to zero upon origination, and MUST be ignored and preserved
   unmodified by other NSH supporting elements.  At reception, all
   elements MUST NOT modify their actions based on these unknown bits.

   Length: The total length, in 4-byte words, of the NSH including the
   Base Header, the Service Path Header, the Fixed Length Context Header
   or Variable Length Context Header(s).  The length MUST be 0x6 for MD
   Type equal to 0x1, and MUST be 0x2 or greater for MD Type equal to
   0x2.  The length of the NSH header MUST be an integer multiple of 4
   bytes, thus variable length metadata is always padded out to a
   multiple of 4 bytes.

Lacking some time before the telechat, but not worth deferring (there are
enough DISCUSS'). FYI, I arrived at section 5.

---

From: <[email-masked]>
Date: Thu, 28 Sep 2017 14:24:18 +0000

Hi Benoit, 

Please see inline.

Cheers,
Med

> -----Message d'origine-----
> De : sfc [mailto:[email-masked]] De la part de Benoit Claise
> Envoyé : jeudi 28 septembre 2017 15:56
> À : The IESG
> Cc : [email-masked]; [email-masked];
> [email-masked]; [email-masked]; [email-masked]
> Objet : [sfc] Benoit Claise's No Objection on draft-ietf-sfc-nsh-25: (with
> COMMENT)
> 
> this point in time.

[Med] Aren't these mentions sufficient? 

   This specification does not make any assumption about Context Headers
   that are mandatory-to-implement or those that are mandatory-to-
   process.

And 

   No initial values are assigned at the creation of the registry.

 Indeed, "New IETF Assigned Optional Variable Length
> Considerations" section. Where is my "Operational Considerations"

[Med] Already covered in the SFC architecture (RFC 7665):

   SFFs maintain the requisite SFP forwarding information.  SFP
   forwarding information is associated with a service path identifier
   that is used to uniquely identify an SFP.

> is important, right?

[Med] The notion of order in the opaque 16-byte block does not make in this spec. How that block is structured is really out of scope. 

 Should it be mentioned?

[Med] I don't think so.

 I understand that the fixed
> length

[Med] The agreement in the WG is to publish documents specifying MD#1 as informational documents. IANA is not involved in this process, because there is no expected action with regards to MD#1 context headers. 

> _______________________________________________
> sfc mailing list
> [email-masked]
> https://www.ietf.org/mailman/listinfo/sfc

---

From: "Carlos Pignataro (cpignata)" <[email-masked]>
Date: Thu, 28 Sep 2017 14:39:50 +0000

Hi Benoit,

There is one final comment below that remained without a response:

On Sep 28, 2017, at 10:24 AM, [email-masked]<mailto:[email-masked]> wrote:

Hi Benoit,

Please see inline.

Cheers,
Med

-----Message d'origine-----
De : sfc [mailto:[email-masked]] De la part de Benoit Claise
Envoyé : jeudi 28 septembre 2017 15:56
À : The IESG
Cc : [email-masked]<mailto:[email-masked]>; [email-masked]<mailto:[email-masked]>;
[email-masked]<mailto:[email-masked]>; [email-masked]<mailto:[email-masked]>; [email-masked]<mailto:[email-masked]>
Objet : [sfc] Benoit Claise's No Objection on draft-ietf-sfc-nsh-25: (with
COMMENT)

- Section 2.5.1., you might want to mention that no metadata are specified
at
this point in time.

And

- Section 2.3
OPS question: SPI must be unique per admin domain? Otherwise, you're
looking
for trouble, right? This would be typically addressed in an "Operational
Considerations" section. Where is my "Operational Considerations"
section...?

- Section 2.4
Fixed length metadata.

I understand that the order of the metadata in the Fixed Length Context
Header
is important, right?

Should it be mentioned?

[Med] I don't think so.

I understand that the fixed
length
metadata are specific per service, and that's the reason why there is no
IANA
for fixed length. Should this be mentioned?

Done (in the working copy).

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Thanks!

Carlos.