[cisco-voip] Quick failover and SRST

[Lelio Fulgenzi]

I have seen minutes go by before a phone registers to SRST. It has to do with the timeouts and retries connecting to the CallManagers though. We have three listed so it takes up to 6 1/2 minutes with the default timers on a VG224 for example. A phone takes about 2 to 3 minutes (you can't change the timers for the phones). You could lower the number of subs in the phone list to speed things up a bit i guess. 

You'll have to pay for it one way or another, hardware (ISR vs MCS) and licenses (SRST vs node license). In v8 and new licensing you could put a server out there a bit cheaper now. You would maintain all functionality as well as a speedier recovery (using the local server as the primary would have no downtime at all). 

But there's something about having to maintain a box out there that just doesn't sit well with me. Setting up an SRST box is pretty much set it and forget it. 

If you don't have a lot of WAN outages, it's not a bad compromise. 


--- 
Lelio Fulgenzi, B.A. 
Senior Analyst (CCS) * University of Guelph * Guelph, Ontario N1G 2W1 
(519) 824-4120 x56354 (519) 767-1060 FAX (JNHN) 
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 
Cooking with unix is easy. You just sed it and forget it. 
- LFJ (with apologies to Mr. Popeil) 



From: "David Zhars" <dzhars at gmail.com> 
To: cisco-voip at puck.nether.net 
Sent: Sunday, December 12, 2010 10:28:04 AM 
Subject: [cisco-voip] Quick failover and SRST 

We have 7 buildings all connected via fiber. Each building has a 2801 for SRST and 911 handling. 

As an upgrade, we are going to install a redundant CM (version 8.x). I have one site that needs quick failover, and most of the reading I have done implies about 40 seconds is required to recognize failure of the primary, and initiate handoff to the subscriber. I know there are some settings to speed this up as well. 

My quesiton is, should I keep SRST now that I will have redundant CMs? Could they somehow assist in that 40 second timeframe, or are they sort of the subscriber when you don't have a redundant CM? What would I gain by keeping SRST with a redundant CM? 

And I'm just curious, but how does Cisco license the redundant CM? Same prices and maintenance as a regular CM? 

thank you! 

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