Re: Does AS marks entire SG congested, when SCON is received on one of two PSPs configured with SG.

Vikramjeet,

I am not familiar with the term "PSP" in this context, so
I'll read PSP1 and PSP2 as ASP1 and ASP2.  Alternatively
they could be SGP1 and SGP2. I am sorry if my assumptions
are incorrect.

Specific reading of the M3UA RFCs suggests this:

Because the [SGP at the] SG has not sent an SCON message to all 
of the "concerned" ?SPs", it doesn't apply to all of the ?SPs.
If the ultimate SS7 destination PCx itself is congested, then 
the SG [SGPs] should sebd an SCON to all "concerned" ASPs (from 
all relevant SGPs).

From an SGP perspective, acting on SS7 status, RFC 4666
Section 4.5.1 states in part:

   In this way, all ASPs configured to send/receive traffic 
   within a particular Network Appearance are informed.  If 
   the SGP operates within a single SS7 Network Appearance, 
   then all ASPs are informed.

But an SCON message can also be a response to a message in 
the other direction: perhaps only ASP1 sent such a message
(see RFC 4666 Section 3.4.4).

I would interpret your scenario to mean that PCx is congested 
when reached through ?SP1, and should be marked so, but no such
congestion is to be inferred for PCx reached through ?SP2.
Perhaps the reported "congestion" is at the ?SP1 interface 
or route to the SS7 network and does not apply to ?SP2.

This is just my interpretation.  With thanks, Chris Benson.

On Tue, 16 Nov 2010, SINGH, VIKRAMJEET (VIKRAMJEET) wrote:

>>  Date: Tue, 16 Nov 2010 12:40:35 +0530
>>  From: "SINGH, VIKRAMJEET (VIKRAMJEET)" <[email protected]>
>>  To: "[email protected]" <[email protected]>
>>  Subject: [Sigtran] Does AS marks entire SG congested,
>>      when SCON is received on one of two PSPs configured with SG.
>>  
>>  
>>  
>>  Hi All,
>>  
>>  AS ------------------PSP1-----------<--<<SCON-----SG (PCx)
>>     ------------------PSP2--------------------------
>>  
>>  
>>  AS is configured with SG with 2 PSPs configured bwtween them.
>>  
>>  In AS M3UA Route configuration :2 PSPs configured with SG with Remote DPC=x.
>>  
>>  SCON is sent from SG to AS with affected PC.x on PSP1.
>>  
>>  Query: Would SG be marked as congested  or PSP2 would be available for traffic?
>>  
>>  -Thanks,
>>  Vikramjeet Singh
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