nevermind, what i wrote doesn't make any sense.<br><br>I assume it must work something more like, the phones follow the SCCP keepalive timers defined in the ccmadmin service parameters but when the KA ACKs begin to fail the phone must use some 'geometric TCP' logic to force a quicker failover.<br>
<br><div class="gmail_quote">On Mon, May 11, 2009 at 2:21 PM, Justin Steinberg <span dir="ltr"><<a href="mailto:jsteinberg@gmail.com">jsteinberg@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
interesting. I must have missed this new addition to 7.2(1). So, this means that with Geometric TCP enabled the phones don't really use the SCCP keepalive timers configured in the CCMADMIN service parameters section? They basically come up with a baseline TCP RTT and failover after that interval passes three times without any response?<div>
<div></div><div class="h5"><br>
<br><div class="gmail_quote">On Mon, May 11, 2009 at 1:18 PM, Wes Sisk <span dir="ltr"><<a href="mailto:wsisk@cisco.com" target="_blank">wsisk@cisco.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
One more variable I do not see in Ryan's response - Geometric TCP. With Geometric TCP enabled the phones failover MUCH more aggressively. With this phone may determine CM is down with only 1.5 second network outage. With Geometric TCP disabled phone may wait up to 45 seconds to classify cm as "down" and attempt failover.<br>
<br>
CSCsm81227.<br><font color="#888888">
<br>
/Wes</font><div><div></div><div><br>
<br>
On Monday, May 11, 2009 11:55:08 AM, Ryan Ratliff <<a href="mailto:rratliff@cisco.com" target="_blank">rratliff@cisco.com</a>> wrote:<br>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
So coming back from SRST there are 3 things that have to happen before the phone will re-register.<br>
1. Establish TCP connection to one of the CMs<br>
2. Wait out the "Connection Monitor Duration" timer so it knows the connection is stable (Enterprise Params, default 120 secs)<br>
3. Request and receive a registration token from the server indicating that it can proceed with registration.<br>
<br>
Both connection monitor duration and the registration token mechanisms are in place to make sure the failback process is as fast and problem-free as possible.<br>
<br>
In your case is there anything between the sites that could be proxying the tcp connection from phone to CCM? All "Standby" means is that there's a TCP session established but it's not actually registered.<br>
<br>
Your best bet is going to be to reset the phone and get a packet capture. look at the traffic on tcp 2000 to the CCM servers to see what's going on.<br>
<br>
-Ryan<br>
<br>
On May 11, 2009, at 11:43 AM, Scott Voll wrote:<br>
<br>
no<br>
sub<br>
pub<br>
srst<br>
<br>
<br>
all via IP addresses<br>
<br>
sub -- Standby<br>
pub<br>
SRST -- Active<br>
<br>
Scott<br>
<br>
On Mon, May 11, 2009 at 8:41 AM, Ryan Ratliff <<a href="mailto:rratliff@cisco.com" target="_blank">rratliff@cisco.com</a>> wrote:<br>
On the phone what is the list of Communications Manages? Does it somehow think the SRST is higher in priority than the sub?<br>
<br>
-Ryan<br>
<br>
<br>
On May 11, 2009, at 11:29 AM, Scott Voll wrote:<br>
<br>
I'm banging my head on a wall. What am I missing?<br>
<br>
have a remote site over IPSEC VPN connection back to central CM cluster.<br>
<br>
all has been working fine. but today I find that the three phones (all) are in SRST mode. the VGW is still registered to the cluster. but from the web interface of the phones shows reg'd with SRST and standby with SUB. How does that work?<br>
<br>
I don't really understand the logs on the 7942.<br>
<br>
I can ping from the sub and pub to the phones. any ideas?<br>
<br>
I can attach logs from the phone is that helps.<br>
<br>
Thanks<br>
<br>
Scott<br>
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