Subject: [Sip] Changing route set in SIP outbound

From: Avshalom Houri <[email-masked]>
Date: Mon, 3 Jan 2011 17:25:18 +0200

Assume that the first SIP proxy that is part of the route set (in SIP 
outbound)
crashes and immediately restarts, or a backup proxy takes over. Is there 
any way to keep the dialog alive if either of the
endpoints senses this failure and recreates a connection or the dialog is 
doomed and needs to be
fully recreated again? The issue is that the route set includes the 
connection information, which is no longer valid.

tnx
avshalom

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From: "Worley, Dale R (Dale)" <[email-masked]>
Date: Mon, 3 Jan 2011 10:26:35 -0500

________________________________________
From: [email-masked] [[email-masked]] On Behalf Of Avshalom Houri [[email-masked]]

Assume that the first SIP proxy that is part of the route set (in SIP outbound)
crashes and immediately restarts, or a backup proxy takes over. Is there any way to keep the dialog alive if either of the
endpoints senses this failure and recreates a connection or the dialog is doomed and needs to be
fully recreated again? The issue is that the route set includes the connection information, which is no longer valid.
________________________________________

As you phrase the question, the *dialog* cannot be kept alive if the connection in question is lost because the route set cannot be changed.

Dale

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From: aayush <[email-masked]>
Date: Mon, 3 Jan 2011 21:10:13 +0530

The route set cannot be changed mid dialog.

Regarding the endpoint detecting the crash of an intermediate proxy,there is
a periodic session refresh mechanism available in SIP which the endpoint
must support.

This mechanism is implemented by examining the Session-Expires and Min-SE
headers.

Conversely if a backup proxy takes over the crashed one, then both proxies
(Active-Stabdby) must support Virtual IP failover for implementing this
fault tolerance use case.

On Jan 3, 2011 8:59 PM, "Worley, Dale R (Dale)" <[email-masked]> wrote:

________________________________________
From: [email-masked] [[email-masked]] On Behalf Of Avshalom
Houri [[email-masked]]

crashes and immedia...

As you phrase the question, the *dialog* cannot be kept alive if the
connection in question is lost because the route set cannot be changed.

Dale
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From: "Nataraju A.B" <[email-masked]>
Date: Tue, 4 Jan 2011 19:06:34 +0530

AFAIU, Any proxy which forms part of the route-set during call setup. It
must support backup and recovery mechanism.

One simple  example where the proxy supports billing functionality could be
part of the route-set and it shall support back and recovery. In this case
it shall back back up all the necessary data to recover if there is any
failure in the active unit. Otherwise it does not make sense to to be part
of a route-set.

On Mon, Jan 3, 2011 at 9:10 PM, aayush <[email-masked]> wrote:

> Regarding the endpoint detecting the crash of an intermediate proxy,there
> is a periodic session refresh mechanism available in SIP which the endpoint
> must support.
>

-- 
Thanks,
Nataraju A.B.