3 phones intermittently dropping calls

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Nov 11th, 2008
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We are experiencing intermittent dropped calls on 3 phones; (2) 7942s and (1) 7962. The drop calls happen between IP-phone-to-IP-phone and IP-phone-to-voice-gateway. The network consists of 5 Catalyst 4510's, 1 stacked 3750; 1 3845 (voice gateway); and CUCM 6.1(2) subscriber. The network is a hub and spoke configuration. We are routing between VLAN's using IP routing on the one of the MDF 4510.

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Tim Smith Wed, 11/12/2008 - 04:36
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This is not the right forum for this one..

But as a start.. have you checked the basics?

I.e Check your switch / router logs on the network? Ensure the layer 2 and layer 3 topologies are stable?

I guess you have a couple of main points of failure..

1. Actual layer 2 / 3 media path between the phones and voice gateways

2. For IPhone to Iphone, you have possibility of dodgy firmware

3. For Iphone to voice gateway, then you could also have circuit / gateway problems

Since point 1 is common to all calls.. check it first.

Point 3 is also fairly easy to rule out by checking your gateway conifg, logs and basic show controller / show interface commands.

For other investigation, check CDR for call disconnect causes. Then onto CCM traces etc.




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