SRST // call forward

Unanswered Question
Jul 1st, 2010
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If a site goes into srst mode:

If they had their phone forwarded, will it “stay” forwarded and will that keep working?

Can users forward / unforward their phones while in srst?


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Rob Huffman Thu, 07/01/2010 - 08:44
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Hi there,

The Call Forward setting is lost during SRST except for Call Forward Unregistered;

This good TAC doc

Core Issue

IP phones continue to send keep alives to the Cisco CallManager every 30 seconds. When the link goes down, the keep alives are missed. Once there are three consecutive keep alive misses, the IP phone un-registers with the Cisco CallManager and the phones register with the Survivable Remote Site Telephony (SRST) router. Since it is set to three consecutive keep alive misses, it takes 90 seconds for the phone to register with the SRST router.


During SRST failover, the phone unregisters with any or all CallManagers which hold the call forward destinations. All call forwarding information is lost if a phone loses the connection to the CallManager it is registered to and registers with SRST.

Incoming calls that reach a busy signal or go unanswered during Cisco CallManager fallback can be configured to forward to one or more E.164 numbers. This is where the Call Forward Unregistered kicks in.


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