Subject: RE: [Sigtran] M3UA - ASP database equalization

From: "TOLGA ASVEREN" <[email-masked]>
Date: Thu, 6 Feb 2003 15:17:17 +0200

I see RC as the main construct of communication between ASP and SGP (which
mimics MTP3/MTP3-User relationship) So, I would prefer to keep RC for any
message between ASP and SGP. It can be thought (although maybe somehow
implementation dependent) that each AS will correspond to a MTP-SAP on ASP.
RC in the incoming messages helps to route those messages easily to the
corresponding MTP-SAP.

I think also the assumption that all AS will have the same destinatin
availability may not hold if AS have RKs with different DPC values.

Furthermore, if we consider dynamic registration, for an ASP, which did not
register yet, which RC value will be put to the SSNM, if we want to send
SSNM while ASP is INACTIVE.

I personally don´t see a significant benefit in either approach from
message exchange point of view. And for the argument that standby ASP
should start working properly as soon as possible, I would say:
a) Better use loadsharing(or even maybe broadcast) mode of operation
b) Synchronize also destination availability (in addition to other things
which need to be synchronized) between active/standby ASPs.
c) Start DAUD procedure when standby ASP goes ACTIVE or consider all
destinations available and update the database based on DUNA received from
SG(already presented during this thread a few times)

But I think RFC uses the word SHOULD NOT, about SG sending SSNM to INACTIVE
ASP. So, it is not a MUST.

I would think keeping RFC as it is now should be fine but I also agree that
this is quite gray area.

Bidolock,,

> -----Original Message-----
> From: Brian F. G. Bidulock [mailto:[email-masked]]
> Sent: Thursday, February 06, 2003 1:35 PM
> To: Zannin, Francois
> Cc: Samuel Dur D. Jeyaseelan; Nagar, Ashish; [email-masked]
> Subject: Re: [Sigtran] M3UA - ASP database equalization
>
>
> Zannin,,
>
> So you see that there are ASP that do not want to receive
> SSNM for inactive AS.  This is one reason why the SG cannot
> be required to send such useless SSNM to inactive ASPs.

If an ASP do not need to receive SSNM, it just do not send the ASP UP.
As soon as the ASP is ready to activate an AS, it sends the ASP UP, and
then it is notified by the SSNM.
SSNM reflect the state of a ss7 SP and is valid for all AS of the same
NA, so receiving a SSNM for one or several AS is the same thing.
If you receive a SSNM for one AS, it is valid for all AS of the same NA.
If you don't need to receive SSNM,,,,  don't send the ASP UP.

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---

From: "Richard Adams" <[email-masked]>
Date: Thu, 6 Feb 2003 14:49:31 +0100

Francois,
According to Q.704, section 2.3.1 last clause, routing to a destination
can depend upon the SI (unfortunately!).
Most existing SS7 MTP implementations I know of consider just the DPC,
not the DPC+SI, when selecting
the linkset or combined linkset to use towards the destination, but they
COULD also consider
the SI. So, the routeing towards the destination could be different for
different SIs. And there
is no imperative to use as alternative routes those used by other SIs.
The routeset for
DPC "D" + SI "S"  might be different (i.e. have other routes) to that
for "D" + all other SIs than "S".
It's awkward, probably pathological, but exists.

-----Original Message-----
From: Zannin, Francois [mailto:[email-masked]]
Sent: 06 February 2003 14:30
To: [email-masked]
Cc: Samuel Dur D. Jeyaseelan; Nagar, Ashish; [email-masked]
Subject: RE: [Sigtran] M3UA - ASP database equalization

<<<snip>>>
The state of a ss7 network destination is the SAME on a SG for all users
(remote AS).
[RAA] Not quite.
DUNA/DAVA/DRST reflects the state of the PC.
[RAA] almost, but not quite. It reflects the state of the routeset used
by the SG to get to the DPC. [RAA]
DUPU reflects the state of a SI on a SP.
[RAA] Agreed.

UNLESS special SG that locally allows an AS to use or not a destination,
this behavior means that a SG can see a ss7 destination but prohibits an
AS to use it! In that case, the SSNM do not reflects the state of a
destination but a management state on a SG for a couple (M3UA-AS <-> ss7
Destination)! Very tricky SG to manage.

[RAA] Agreed. And I would hope network operators wouldn't ask for this,
but 
I have seen some requests in the past! [RAA]
Kind regards,
Dick Adams,
[email-masked]