IPO 500 H323 phones intermittent dial tone issues

[wingnutkev]

We have an IPO 500 8.1(69) in a rack-space with public IPs assigned. I currently have 5 sites with phones connecting to the system using SIP trunking.
System: Hosted by customer with two bonded T1s for internet access, no firewall.
Site 1: has a T1 ISP, Cisco ASA firewall, experienced no issues
Site 2: Home user Cable internet, unsure about firewall or ISP, no issues
Site 3-5: All have Comcast Business Class with Cisco ASA firewalls and all experience intermittent issues of going off hook and not receiving a dial tone.

We have all 9611 phones, latest firmware 6.22.09. When the issue occurs, the phone does not loose registration, Monitor shows it going off hook and everything to me looks like any other call. The issue will last anywhere from 30 seconds to about 2 minutes then corrects itself. I don't recall at this point if you dial if a call goes through or not, users are just reporting no dial tone and they reset their phone.

The firewall settings are the same with site 1 and 3-5, I don't suspect a firewall issue. I suspect a Comcast modem or service issue. Is there anything you have seen in the past, a setting in the Comcast modem perhaps, that I may be missing that could cause something like this? This is the first site we have set up without MPLS or VPN connectivity so I'm not sure what else to look for.

Thanks in advance for any help of direction

 

[amriddle01]

The IP Office is not the system to use to provide a hosted service, Cisco routers will often break NAT'd phones as Avaya haven't implemented it very well



"No problem monkey socks

 

[wingnutkev]

I wanted to add that it doesn't affect the whole site at the same time, it usually happens to one phone at a site at a time. I think there is a session timer in play here that times out eventually after some amount of idle time then resets.

 

[tlpeter]

Kick some as at Comcast.
This is not an IPO issue as the traffic is blocked at the router.

BAZINGA!

I'm not insane, my mother had me tested!