Phones Randomly Lose Dial Tone

[adam307]

Hi,
I have Avaya 9611G phones. Randomly one will lose dial tone. The next day it will work again. This has been going on for a year or more and we have not been able to make any progress in figuring this out. Until today while in testing we were able to move the affected phone's IP address to a working phone. This phone then lost its dial tone. I cleared the original phone and it grabbed a new IP address but still had no dial tone. Any IP address put into the original non-working phone seems to become infected. Any phone that boots up and grabs an infected IP will have no dial tone. This is not limited to 9611G phones. I plugged in a 9620 and it pulled an infected IP and it has no dial tone. Phones in other regions do not seem to be affected, only phones in our region 1. Any ideas or tips would be greatly appreciated.
Thanks,

 

[kyle555]

A station trace while it's happening and not happening would tell you what ports/what gateway you're using.

Presuming they're H323, the media ports they're told to use are defined in the ip-network-region form. I *believe* CM may cycle through the range incrementally as RTP sessions are requested - like going off hook.

So, if you've got the default range of 2048-3329 and somewhere a firewall or access list is blocking 3000-3329, then only media requests on ports 2048-2999 would get audio back from the gateways for dialtone.

Presuming the DSPs are CM are in the same subnet/behind the same network security, then you're also saying that h323 signaling on port 1719/1720 is always working. To say, you go off hook, CM acknowledges your primary call appearance is in use, and you still have no dial tone.

Your ip-network-region design is also up for discussion. DSP selection is a detailed topic.

Consider this: a region with phones and no DSPs has 'direct WAN' as 'yes' to every other region.

In that example, every time a phone in that region goes off hook and needs a DSP for dial tone, CM would presume all gateways are equally distant, available and eligible to provide that dial tone. If your phone is in NY and you have no IP routing or ports open for RTP from CA to NY and at the time you went off hook, NY was rather busy and its DSPs were more heavily used than CA's, CM might decide for load balancing purposes that using a CA DSP would be best and you'd hear nothing.