Re: aspcong draft -congestion levels-

Tolga,

Tolga Asveren wrote:                    (Thu, 20 Oct 2005 11:43:40)
> IMHO, it is not that straightforward what to do about improved TID based
> routing support. First let't see what TCAP and SCCP provide:
> 
> SCCP: transport functionality
> TCAP: asynchronous remote procedure call semantics
> 
> As far as I can see, one can't just provide TCAP-User interface to
> applications and expect them to do something usefull, they need to receive
> SCCP primitives as well to decide reachability of destinations. So, there is
> no architecturally pure solution to that problem, any solution mimicing TCAP
> user-interface should also include transport related messaging like
> DUNA/DAVA etc... , which is not part of TCAP-user interface.

On the contrary, the TCAP-user interface described in the Q.77X series
of specifications, does include primitives for the availability and
reachability of destinations.  They happen to be the same as the SCCP
ones:

 Q.771/2.2.3 Management aspects

 SCCP Management primitives used to inform SCCP users of availability
 and non- availability of SCCP (local or remote), wil be passed
 transparently by TC to the TC-user.

That's pretty clear.  draft-bidulock-sigtran-tua-04.txt provides
DUNA/DAVA/DRST/SCON in the same fashion as SUA to accomodate this.
These are summarized in section 1.3.5.3 of the draft and detailed in
Sections 3.5.1 (DUNA), 3.5.2 (DAVA), 3.5.3 (DRST), 3.5.4 (SCON),
procedures in 4.1.2.1, and all of 4.5.

> 
> Considering the distributed architecture of SIGTRAN UA protocols, all of
> them also have some transport functionality in that context, e.g. ASPs may
> communicate with multiple SGPs adn based on reachability information of the
> SGPs, status for SS7 destinations may change as well.
> 
> It seems, a SCCP User-Interface based solution would need to perform some
> TCAP processing to be able to support improved TID based routing. Similarly
> a TCAP User-Interface based solution needs to implement some transport
> related functionality and should support transport of SCCP primitives, which
> is not what TCAP is doing.

No, I'm sorry, but that is simply wrong: SCCP management is included in
TCAP per TCAP standard specifications.  TUA simply follows standard TCAP
in passing SCCP management messages transparently to the TC-User, and
even does so with the same semantics and syntax of SUA.

--brian

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