Subject: RE: [Sigtran] Congestion in M3UA/SUA and the use of the SCON

From: "Haresign Lincoln" <[email-masked]>
Date: Mon, 10 Oct 2005 14:38:13 -0400

Brian,

When talking about SUA, GTT can be performed in the SG.  However, there
is no requirement to modify the called address to PC/SSN.  In some
architectures, there is absolutely no need to know the PC/SSN if you are
working strictly with GTs.  And in some architectures, this certainly
simplies the provisioning.  Where does it say otherwise in any
requirement (SS7 or SIGTRAN)?

There is no need to perform GTT in an ASP.

I'm not sure where the disconnect is.  I'm quoting from the RFCs.  

The RFC says:

1) An ASP can send an SCON to a SG.

2) When an ASP talks to an SG, it does not need to know it's point code.
It's not a required parameter in dynamic registration.  It's not a
required parameter in the CL messages.  

Therefore, one can only infer that if the ASP wants to use the SCON
message to invoke the subsystem congestion procedure on the SG, the ASP
must be able to send an SCON message to the SG without knowing it's
point code.  In other words, if affected PC should NOT be a required
parameter when sending an SCON from the ASP to the SG.  There is a hole
in the specs.  I will propose alternate language to fill the hole when I
get a chance.

Regards,
Lincoln 

-----Original Message-----
From: Brian F. G. Bidulock [mailto:[email-masked]] 
Sent: Monday, October 10, 2005 1:21 PM
To: Haresign Lincoln
Cc: Tolga Asveren; [email-masked]
Subject: Re: [Sigtran] Congestion in M3UA/SUA and the use of the SCON

Haresign,

Haresign Lincoln wrote:
(Mon, 10 Oct 2005 08:56:29)
> Brian,
> 
> With regards to SUA, I believe you might be mistaken.  There is no 
> requirement to have a point code in the message recevied by SUA.  The 
> message received will have a called and calling address.  These 
> addresses could be global titles with no point code.

Only at a relay node.  Which is an SG or IPSP.  No ASP.  An ASP is an
end-point.

> 
> So again, if the ASP wants to indicate congestion back to the GW, it 
> has no way to specify the affected PC.

An ASP always has a point code because final GTT has always been
performed at an ASP.

--brian

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

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---

From: "Brian F. G. Bidulock" <[email-masked]>
Date: Mon, 10 Oct 2005 15:20:57 -0600

Haresign,

Haresign Lincoln wrote:                                                           (Mon, 10 Oct 2005 14:38:13)
> required parameter in the CL messages.  

An AS does not need to know its point code to receive messages.
However, if SUA at th ASP is going to take responsibility for SCCP
congestion procedures, it needs to know which SCCP it is signalling
congestion for, and the instance of SCCP is identified by the MTP-SAP
which includes the point code.  This is nicely reflected in the fact
that the Affected Point Code is mandatory in the SCON if it is sent
from ASP to SG.

Sending SCON is optional.  If your ASP doesn't know its point code,
simply don't send SCON from ASP to SG.

--brian

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