Subject: [MBONED] AMT draft / refreshing state on relay + editorial comments

From: Thomas Morin <[email-masked]>
Date: Thu, 11 Mar 2010 15:54:34 +0100

Hello,

Since the discussion is still ongoing on some aspects, I'm taking the
opportunity to sent a comment on when/how is state refreshed on the relay.

Section 5.1.3 says:

   o  The Relay responds to the AMT Request message by returning the
      nonce from the Request in a AMT Query message.  The Query message
      contains an IGMP/MLD QUERY indicating how often the Gateway should
      repeat AMT Request messages so the (S,G) state can stay refreshed
      in the Relay.  The Query message also includes an opaque security
      code which is generated locally (with no external coordination).

I have the following comments:
- this text is not very precise on the IGMP/MLD Queries that are
included in AMT Query messages... If I understand correctly, these are
General Queries (and not Specific Queries). If so, this precision should
be added.
- the text implicitely says that if no refresh is made some text will
expire, it would be nice to have some text saying explicitly that the
relay will (and has to) cleanup S,G state associated with a gateway, and
give the required precision  on the period after which this will happen
- based on the above, the text could be made clearer on the following:
   - what is the info duration in the IGMP/MLD packet that determines
when "something" must be repeated: Query Interval ? Max Response Time ?
   - what is to be repeated in due time : I would think that a
Membership Update should be sent in due time before some S,G state
expires, but the text above could mean imply that a Request would
refresh (S,G) state...?
   - how is RTT taken into account in this step  ?

I also have a bunch of very minor editorial comments on the rest of the
document:
- 6.3 on AMT Request: -> diagram legend should read "AMT Request" (and
not "AMT Advertisement" as it currently does)
- 6.4.4: about the nonce in an AMT Query: nonce is said to be "used to
distinguish this request echoed back to the originator"; it should I
think instead say something like "it is echoed back to the request
originator to identify the corresponding request"
- 6.5.4: similar as above, about the nonce in the membership update:
nonce is said to be "used to distinguish this request" while it is used
in fact "to identify the corresponding request"
- 6.4.5: "outer header" -> "outer IP header" (same for "inner header") ?
- 9.2 IANA considerations: says "It should also be noted that this
prefix length"
  -> what do "this prefix length" and "also" refer to ?
  -> it seems that something is possibly missing, perhaps a introductory
sentence like the one starting section 9.1 ?

Of course, since I'm well past the WGLC, so you are free to send these
comments to the bit bucket...

Cheers,

-Thomas