[homenet] Updates to Homenet Architecture Principles doc

[Ray Bellis <[e-mail]>]

[let's try that again, hopefully without b0rked line wrapping]

Dear Working Group,

You may have noticed multiple revisions of draft-ietf-homenet-arch posted recently. After many iterations and a ton of work for our Editor In Chief, Tim Chown, all IESG “DISCUSS” positions have been resolved to either “Yes” or “No Objection”, with the exception of one “Abstain” from one of our Routing Area ADs who had requested that the following text be added to section 3.5:

“Routing within the homenet will determine the least cost path across
 the homenet towards the destination address given the source address.
 The path cost will be computed as a linear sum of the metric assigned
 to each link.  The metric may be configured or automatically derived
 per link based on consideration of factors such as worst-case queue
 depth and router processing capabilities.”

The Chairs felt that the first half of this text was unnecessarily prescriptive for this document and did not reflect something the WG had achieved consensus on at this time.  We proposed a compromise that incorporated the latter non-normative half of this text in an earlier paragraph.  On the basis that we understood that this compromise had been accepted by the respective AD, the -14 revision was posted.

After -14 was posted and the AD’s position changed to "No Objection", we noticed that the above paragraph had inadvertently been included, in full, in addition to the latter half included as part of the proposed compromise! At the Chairs’ request, Tim removed the above paragraph in -15, which caused the AD to object as it appeared to him that his text was being removed after the fact.

Later today, Tim will be posting a -16 revision of the document that reinstates the above paragraph, in full, and removes the “compromise” text. On the basis that the new text is a potentially substantive change, our AD has requested that we put the document through one more Working Group Last Call to determine WG consensus on that issue.

In addition, one small change was introduced in the -15 revision based on WG feedback where a reference to Source Specific Multicast [RFC 4607] was introduced, but had not been called out explicitly in London or before. That change is as follows:

Old:
 It is desirable that, subject to the capacities of devices on certain   media types, multicast routing is supported across the homenet.

New:

  It is desirable that, subject to the capacities of devices on certain
  media types, multicast routing is supported across the homenet,
  including source-specific multicast (SSM) [RFC4607].

The WGLC will commence immediately after the -16 is posted, and will last for two weeks.

We very much want your feedback here, but are not aiming to revisit the document in its entirety. As such, we would like to limit the scope of the WGLC to just the text quoted in this email.

Many thanks,

Ray and Mark