From: Pradeep4 Kumar <pradeep4.kumar@aricent.com>
To: David Laight <David.Laight@ACULAB.COM>, gitam changkakoti
 <gitam.changkakoti@live.in>, "sigtran@ietf.org" <sigtran@ietf.org>
Thread-Topic: [Sigtran] Sigtran interworking issue between multivendor node
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Date: Tue, 26 Jul 2016 10:37:15 +0000
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Subject: Re: [Sigtran] Sigtran interworking issue between multivendor node
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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 SC=
TP at least one major manufacturer has a configuration option where M3UA IP=
SP 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 su=
pport 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 f=
or section 1.5.3.    As I check the RFC4666 section 1.5.3, there is no ment=
ion 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:David.Laight@ACULAB.COM]
Sent: Tuesday, July 26, 2016 3:06 PM
To: Pradeep4 Kumar <pradeep4.kumar@aricent.com>; gitam changkakoti <gitam.c=
hangkakoti@live.in>; sigtran@ietf.org
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 I=
PSP 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 a=
s "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 li=
nks 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 th=
e justification (or documentation!) of this unusual mode.

David


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