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IP Phone Keepalive time to Primary Callmanager

chan-kuen.hui
Level 1
Level 1

Dear All,

After the IP Phone register with Primary Callmanager, The IP phone will have TCP Keepalive with Primary CM. What is the default keepalive time? How many of this Keepalive fail so the Phone will switch to secondary CM?

Thanks and Regards,

C.K.

1 Reply 1

mderriennic
Level 1
Level 1

Hi,

Here is the information from the page

IP Telephony: The Five Nines Story

http://www.cisco.com/en/US/partner/netsol/ns340/ns394/ns165/ns268/networking_solutions_white_paper09186a00800a113e.shtml

"Redundant Cisco CallManagers are not currently stateful. This capability is expected in future releases. Currently, a TCP keepalive is sent every 30 seconds. Three simultaneous negative responses cause failover to the standby, which can initiate new calls. Current calls are not dropped during failover however DTMF signaling info is lost and call may be reset. A failed access device will cause a failover to the redundant Cisco CallManager. Because three keepalives can occur in 61 seconds, the mean time before the 1st keepalive is used bringing the average downtime to 75 seconds. Shortly following this, the redundant Cisco CallManager will have the ability to accept new call requests.

"

Regards,

Marc