RE: SUA implementor's guide

I'm curious about this section in the Implementor's Guide:


2.10.3.  Solution description

.........

   Improving the clarity of the use of the TID and DRM label parameters:
   Redundancy - The label values are fixed length (16 bits).  So why do
   we need both a "Start" and an "End" position for applying the mask?
   One or the other would seem to be enough.

   Simplicity - Why bother with a partial-sized mask at a specified
   "start" bit.  Why not just specify a "full-sized" 32-bit (TID) or 23-
   bit (DRM) mask?  Then we do not need a "start" and "end" position.

   Contradictions - Section 4.7.2.1 states that "All the ASPs within the
   AS _must_ specify a unique label at a fixed position in the TID or
   DRN parameter."  The "must" here contradicts that fact the the TID
   and DRM parameters are listed as Optional in the ASPAC msg.  Thus if
   a label is present, then all ASP's belonging to that AS, must
   specifiy a label in the ASPAC msg. 



Should the implementor's Guide being asking questions?  I thought this
was an attempt to clarify, not to ask questions.  I would answer the
questions as follows:


So why do we need both a "Start" and an "End" position for applying the
mask?

You don't need to use all 16 bits.  So in that case, the start and end
give some flexibility as to how you want to use the TID.

Why bother with a partial-sized mask at a specified "start" bit.  Why
not just specify a "full-sized" 32-bit (TID) or 23-bit (DRM) mask?

Again...flexibility.


With regards to the contradictions, I imagine this could be clarified
with something like "If the ASPs are using the TID parameter, then....

Regards,
Lincoln



-----Original Message-----
From: Ong, Lyndon [mailto:[email protected]] 
Sent: Saturday, October 07, 2006 5:22 PM
To: [email protected]; Cullen Jennings
Cc: Barry Nagelberg; [email protected]
Subject: RE: [Sigtran] SUA implementor's guide

Hi Folks,

Now that the SUA Implementor's Guide has been reissued, I'd like to see
if people are ready to do a WG Last Call on it.  If so, we can start
this up next week.

Cheers,

L. Ong 

-----Original Message-----
From: Brian F. G. Bidulock [mailto:[email protected]]
Sent: Tuesday, October 03, 2006 9:59 PM
To: Cullen Jennings
Cc: [email protected]; Barry Nagelberg; Ong, Lyndon
Subject: Re: [Sigtran] SUA implementor's guide

Cullen,

Cullen Jennings wrote:                   (Tue, 03 Oct 2006 21:09:00)
> 
> More importantly, I think some of
> this stuff if sufficiently complicated that outside a somewhat small 
> group of folks, an implementor guide will really help this work be 
> successful.

Well, the implementor's guide is really a specification errata document
and not a guide to the uninitiated.  It assumes, as does the
specification, that the reader has a very solid understanding of the
thing being transported.

--brian


--
Brian F. G. Bidulock
[email protected]
http://www.openss7.org/

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