Re: Congestion in M3UA/SUA and the use of the SCON

Tolga,

Actually, I am not even speaking of subsystem congestion yet (N-STATE)
(which is only detected and signalled by some variants of SS7).  I am
speaking of SCCP congestion (N-PCSTATE).  For heaven's sake, the N-PCSTATE
primitive has PC in the acronym.

I don't really have a problem with a fancy, non-SS7 congestion mechanism.
Just don't use the SCON message.  SCON is a message reserved for SS7 network
interworking.  If you look at the ETSI modified documents, ETSI decided
(whether prudently or not) that if the SG receives a SCON from the ASP that
it MUST send the equivalent SS7 message.  To populate such a message's MTP
header requires the presence of the point code.

We discussed this at great length before.  Leave SCON for SS7 management.  If
you want to signal ASP congestion outside of the mechanisms of SCTP, we need
to define some ASPTM messages to do so.  And that is where we left it.  Nobody
proposed ASPTM messages for congestion indication, and nothing more was done
about it.

Now, again, there is this tendency to try to drag the SCON message to do
things other than SS7 network management, and instead bend it to ASP Traffic
Management.

If SCTP congestion management (peer receive window, send buffer occupancy) is
insufficient, define an ASP Congestion and ASP Congestion Ack message.  Add
an ASP Status and ASP Status Ack message for testing or probing congestion.
But please leave SCON alone.

--brian


Tolga Asveren wrote:                                                                  (Tue, 11 Oct 2005 18:50:06)
> Brian,
> 
> As far as I understand Lincoln wants congestion detection for subsystem to
> happen at SG but
> a)Wants ASPs to help SG in that decision through SCON messages
> b)Wants to use ASP congestion information communicated with SCON from ASP to
> SG, while distributing messages from SG to ASP.
> 
> I would think -although implementation dependent for most of the part- a)
> and b) could be usefull for certain configurations.
> 
> I believe you are approaching the issue from another angle, where you
> foresee a scenario where ASP detects subsystem congestion and communicates
> it with SCON.
> 
> 
>     Thanks,
>     Tolga
> 

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