RE: SG view of the ASP

The ASP is currently sending the ASP UP message with the same ASP Id to
both SGPs. 

As per the SG guys suggestion we temporarily changed the ASP trafficmode
in the ASP ACTIVE message to loadsharing and this problem goes away. But
we see another problem.

The administrator on the ASP side decides to take down the SCTP
association with SGP2. The ASP sends ASP DOWN message to the SGP2. Then
the SGP2 responds with ASP DOWN ACK. So far everything looks good. But
then immediately the SGP1 sends a NOTIFY with the status=ASP Failure and
includes the Routing Context value. Why is the SGP1 sending this NOTIFY
and what is the expected behavior of the ASP upon receiving the NOTIFY
from the SGP1? The SG is sending the NOTIFY because it treats the ASP as
two separate ASPs and so it thinks that it is notifying to the other
ASP.

I think it came down to the way SG was designed - "The SG treating each
association as a separate ASP as supposed to just one ASP with two
associations".  Is this the general way a SG behaves (or designed)?
Should it not treat an ASP as just one rather than two?

Please provide some input so that I can confirm my understanding of the
M3UA protocol.

Thanks,
Krishna

-----Original Message-----
From: Brian F. G. Bidulock [mailto:[email protected]] 
Sent: Thursday, February 09, 2006 12:21 PM
To: Munnaluru, Krishna
Cc: [email protected]
Subject: Re: [Sigtran] SG view of the ASP

Krishna,

I suppose you could try adding ASP Id to the ASP Up message and see
if the SG recognizes the ASP as one.

However, as Ille suggests, perhaps the problem is the SG's traffic
mode (rather than the AS's traffic mode).

If the SG really believes that the ASP is two distinct ASPs, it should
be sending a NOTIFY("Alternate ASP Active") from SGP1.  If it does not,
IMO it is just a bug, so, perhaps the SG does not truly support Active/
Standby mode.

--brian


Munnaluru, Krishna wrote:                    (Thu, 09 Feb 2006 11:34:46)
> Brian,
> 
> This is how it is affecting my expected behavior.
> 
> Note: Currently I have only one ASP but in future I intend to add a
> standby ASP. Hence I use the trafficmode=override in the messages.
Also
> the desired behavior is that the ASP to laodshare the traffic going to
> the SG among the two SGPs.
> 
> The problem showed up during the following scenario:
> 
> The ASP comes up, establishes associations and sends ASP UP message
> (ASPIdentifier = 10007) to both SGPs for which the SGPs respond with
ASP
> UP ACK. 
> 
> The ASP sends ASP ACTIVE (trafficmode=override) with a routing context
> for the AS to the SGP1 and the SGP1 responds with ASP ACTIVE ACK. The
> status on the SG shows that the AS is active on SGP1 and inactive on
> SGP2.
> 
> Later the ASP sends ASP ACTIVE (trafficmode=override) with the same
> routing context to the SGP2 and the SGP2 responds with ASP ACTIVE ACK.
> The status on the SG shows that the AS is active on SGP2 and inactive
on
> SGP1. I was expecting the AS to be active on both SGPs since the ASP
had
> sent ASP ACTIVE to both SGPs.  This was not what I was expecting.
> 
> The explanation given by the Third party SG team is that since they
> treat association from SGP1 to ASP as one ASP (ASP1) and the
association
> from SGP2 to ASP as a separate ASP (ASP2), they are over writing the
> status when the SGP2 received the ASP ACTIVE message from the ASP.
They
> suggest that I put the trafficmode=loadshare and that would solve the
> problem.  So I am really confused.
> 
> Hope this helps.
> 
> Thanks,
> Krishna
> 

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