Re: Re: Can SUA Layer encapsulate MTP L3 layer/functionality?

Brian, and other SIGTRAN community memebers,
   
  I have read that RFC many years ago and do understand it quite well. I think you haven't understand my point with SAAL specifications which I used just as a refference to show what I mean.
   
  Could you please answer this very simple question in very simple way (with YES or NO), which I copy/paste from my previous mail.
   
  "It is clear that SUA adaptation layer must contain SCCP functions. However the question is can SUA layer contain MTP functions? E.g. MTP3 relay?"

  If YES how is the MTP3 functionality supported by SUA protocol if I read:
   
  SUA RFC: sec. 3.4.1. DUNA is meant to replace N-STATE and N-PCSTATE indications...
   
  / Stanislav Ivanovich
   
  

"Brian F. G. Bidulock" <[email protected]> wrote:
  Stanislav,

Adaptation modules are defined as in RFC 2719 Section 3.1, and
*NOT* ATM SAAL specifications.

--brian

Stanislav Ivanovich wrote: (Thu, 26 Jan 2006 10:11:26)
> 
> In addition to the last mail I want to add that it seems that SUA RFC
> provides SCCP alike relay (GT) since this relay is not managed by
> management messages thus no need for DUNA, DAVA messages what makes
> SUA RFC complkiant with the idea of having only SCCP relay in SUA.
> 
> 
> 
> / Stanislav Ivanovich
> 
> Stanislav Ivanovich wrote:
> 
> Hello SIGTRAN community,
> 
> 
> 
> The reason why I am writing this is because I have recently found very
> contradictory statements in this forum which seem to collide with
> relevant specifications. So I would like to hear some comments.
> 
> 
> 
> 
> 
> There is no doubt that there is a very sharp distinction between M3UA
> and SUA.
> 
> 
> 
> M3UA is r! eal adaptation/coordination function which does not contain
> any MTP functionality but like all the other adaptation/coordination
> functions just provides access to functions provided in a substitute
> component.
> 
> 
> 
> Thus for example in case of ITU-T SAAL one can find MTP-alike
> functions in ATM layer, SSCOP (retransmission etc...) so he/she just
> needs a coordination function in SSCF (Q.2140) which does not contain
> real functionality but only coordinates (maps) services expected from
> user to corresponding services in the new component which replaces the
> old ones.
> 
> 
> 
> So like in this ITU-T example M3UA also does not essentially contain
> any MTP functions (that's is why it is called adaptation layer) but
> provides access to MTP-alike functions in new components which replace
> MTP. Thus one can find functionality similar to MTP L3 relay in IP
> layer or data error detection and correction functions of MTP L2 in
> SCTP. So M3UA just pr! ovides access for MTP-users to MTP-alike
> functions in new component (SCTP+IP+Physical layer) which replaces MTP
> layer. M3UA essentially behaves as SSCF of SAAL by coordinating access
> to MTP alike functions in the substitute component.
> 
> 
> 
> 
> 
> 
> 
> However this SUA thing is really not adaptation layer of this kind.
> Does SIGTRAN provide us with substitute for GT, CL, CO... functions of
> SCCP? NO!
> 
> Can one find GT alike function in IP or SCTP? NO!
> 
> 
> 
> So what does SUA adapt?
> 
> 
> 
> It is therefore clear that SUA "adaptation" layer must contain SCCP
> functions.
> 
> 
> 
> However the question is should it contain MTP functions? E.g. MTP3
> relay?
> 
> 
> 
> Looking into SUA RFC it looks like that SUA layer cannot support MTP3
> relay. (e.g. sec. 3.4.1. DUNA is sent only as N-STATE or N-PC-STATE
> indications, and many other similar references...).
> 
> 
> 
> I have also recently heard from people here at the SIGTRAN forum that
> MTP3 relay does not make sense since we have corresponding function in
> IP relay... (when we spoke about SGP-SGP protocol which is being
> developed for M3UA to enable it to contain and use MTP3 relay
> functions).
> 
> 
> 
> If MTP3 functions do not make sense within M3UA how can they make
> sense for SUA?
> 
> 
> 
> thanks for the comments!
> 
> 
> 
> kind regards/ Stanislav Ivanovich
> 
> 
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-- 
Brian F. G. Bidulock
[email protected]
http://www.openss7.org/
  


		
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