Re: Sigtran interworking issue between multivendor node

Hi David,

Thanks for additional info. I had also some more observations as:

Point 1.
">>> Although M3UA almost always carries the MTP3 service interface over SCTP at least one major manufacturer has a configuration option where M3UA IPSP links seems to be used to pass messages between MTP3 systems.
Configured that way it requires the IPSP system to answer DAUD (for its own pointcode) and to not error DAVA and DUNA.
"
In standard systems as per RFC4666, ASP end or IPSP  end does not expect to receive DUAD messages see section from RFC as :

"3.4.3.  Destination State Audit (DAUD)

   The DAUD message MAY be sent from the ASP to the SGP to audit the
   availability/congestion state of SS7 routes from the SG to one or
   more affected destinations
"

However it is always possible to customize the implementation to provide support of SSNM messages over IPSP interface.

2.
"If you look at section 1.5.3 the M3UA connection appears to be an IPSP one between the ASP on the right and SCCP in the middle.
However there is also a direct link shown between the MTP3 and M3UA."

Please let us know which RFC version you are referring in above statement for section 1.5.3.    As I check the RFC4666 section 1.5.3, there is no mention of IPSP there in that model.


Best Regards,
Pradeep Kumar
 "The world needs HQ (Humanity quotient) more than IQ."


-----Original Message-----
From: David Laight [mailto:[email protected]]
Sent: Tuesday, July 26, 2016 3:06 PM
To: Pradeep4 Kumar <[email protected]>; gitam changkakoti <[email protected]>; [email protected]
Subject: RE: [Sigtran] Sigtran interworking issue between multivendor node

From: Pradeep4 Kumar
> I am assuming that the open MGW and AOIP BSC are connection over the
> IPSP communication type. Correct if I am wrong?
>
> IPSP is point to point communication so DAUD is not expected message on IPSP communication mode.
>
> So the receiving end point must drop the DAUD message and also this
> end point can optionally send back Management Error  message with error as "Unexpected Message".
...

Although M3UA almost always carries the MTP3 service interface over SCTP at least one major manufacturer has a configuration option where M3UA IPSP links seems to be used to pass messages between MTP3 systems.

Configured that way it requires the IPSP system to answer DAUD (for its own pointcode) and to not error DAVA and DUNA.

If you look at section 1.5.3 the M3UA connection appears to be an IPSP one between the ASP on the right and SCCP in the middle.
However there is also a direct link shown between the MTP3 and M3UA.
It isn't clear to me which messages would use that link, but it might be the justification (or documentation!) of this unusual mode.

David


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