Re: requirements draft revision

[Brian E Carpenter <brian@hursley.ibm.com>]

My comments on the -01 draft (presumably you will post it officially?)

You define the SHOULD/MUST/etc terminology but don't use it. I think this
is important - some of the requirements should be SHOULDs and some of
them must be MUSTs, but I don't think that is correct yet in the text.
For example, imho 3.1.1 should be MUST, but it starts with a "should".
I suggest a pass through the draft to clarify this everywhere.

3.1.1:

>    The multihoming architecture must accommodate (in the general case,
>    issues of shared-fate notwithstanding) the following failure modes:

I don't find the parenthesis very clear. Suggestion:
  (in general, disregarding the survival of individual sessions 
  as covered by section 3.1.6)

3.1.6:

>    Multihoming solutions must provide re-homing transparency for
>    transport-layer protocols; 

I think we have to be more precise. Firstly it isn't the protocol that
survives, it's the session. Secondly, does this include UDP? Suggestion:

   Multihoming solutions must provide re-homing transparency for
   transport-layer sessions, including protocols such as
   TCP and SCTP, and purely stateless protocols built on UDP.   

[actually what about applications built on raw IP??]

    Brian




Joe Abley wrote:
> 
> Hi,
> 
> I've been sitting on this for a few days now, so I think it's time to
> throw it out for discussion. Note that I haven't given Ben time to check
> this over, so if there are gross errors they are mine and Vijay's, and
> you shouldn't blame him.
> 
> I'm not happy with the requirements on transport-layer stability and
> survivability, but I wasn't able to find clear consensus in the mail
> archives on the issue. Perhaps we can put that issue to bed in -02.
> 
> I have split out the description of v4 multi-homing to a separate
> document, as I think that makes things clearer. The v4 document is
> somewhat green, and could do with some attention (it might be useful to
> re-order the points as a compliance document against the reqs draft,
> for example, so it is more clear where it is deficient and where it
> exceeds the requirements).
> 
> Anyway, flame on.
> 
>   http://www.automagic.org/~jabley/draft-ietf-multi6-multihoming-requirements-01.txt
>   http://www.automagic.org/~jabley/draft-ietf-multi6-v4-multihoming-00.txt
> 
> Joe

-- 
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Brian E Carpenter 
Distinguished Engineer, Internet Standards & Technology, IBM 
On assignment for IBM at http://www.iCAIR.org 
Board Chairman, Internet Society http://www.isoc.org

"We shall need a number of efficient librarian types 
 to keep us in order." - Alan Turing, 1947.