We have a Draytek 2820n with WAN1 set up over a BE internet ADSL connection, and WAN2 connecting to another connection we're supplied with in the building we're renting from.

We have 6 Snom 320 phones connected to a switch which is connected to the router. 5 of the Snom phones are set up with external IPs which we have been given by BE. The phones are set up as per the instructions here . The other phone is set up on the internal LAN, and has been allocated a set 192.168. address according to its mac address.

The phones which have the Public IPs would, I would have though, have to connect to the Internet through WAN1, since that is the connection providing their IPs. The phone which has the internal IP is forced to connect to WAN1 due to the WAN>>Load balance policy forcing it onto WAN1.

Ostensibly, the phones work fine. Calls are clear, and can dial out properly as well as receive and transfer calls just fine. Unfortunately, from time to time, the calls cut out. To be clear, the connection is maintained, but either one end of the call or the other cannot hear the other for a period of time, perhaps 5-10 seconds. If there are multiple calls ongoing, this happens to all calls. This issue occurs to both the phones with the public IPs and the phone with the internal IP.

I've spoken to our telecoms provider (Gradwell) and they have run checks that point to this not being their issue.

Does anybody have any idea what would cause this to happen? And, even better, what could cause this to stop?!

Thanks in advance for your time.

Simon

Hi Simon,

I'm actually experiencing exactly the same problem. Albeit I have 4-5 phones, all of which are just on the 192.168.x.x subnet range inside and share one public IP.

Users report the same problem - callers experience one way audio for brief periods.
Connectivity to the VOIP provider is excellent at ~20ms ping times and I do not see any packet loss when the silence occurs.

I have tried different codec on the Snom 300 phones, problem still remains.

The connection is solely used for these phones there is no other traffic so makes me think its router related rather than a bandwidth / connectivity problem.

Also tried latest firmware on the phones.

Have you been able to resolve this yet?

It did eventually get resolved, though I can't quite remember what it was down to!
I have a funny feeling it may have had something to do with the VLANs, they maybe didn't play together too well with anything else.

Either way, it's sorted now. If you want my cfg file, drop me a line.

That would be great if you could let me see a copy please.
Had raised a ticket there with support also, need to get this resolved.

http://dl.dropbox.com/u/61745/V2820_20101102.cfg

should do it.

Best of luck

Hmmm.....

I've come to this topic a bit late, I'm afraid.

We also had problems with random one-way audio on calls (via Gradwell) on a 2820Vn. The direction of the one-way would be random, as would the length of time it lasted.

Rebooting the router would usually solve the problem for a while.

The situation has been much much better of late but other than updating the router firmware (currently on 3.4.x) we've not done anything else.

We aren't using Vlans though.

Thanks for posting your config Simon. But does anybody know how to "read" a configuration backup .cfg file? We have too many VPN settings in ours and it would be a pain to re-create them, so ideally I'd just like to take a look at what the settings are in that file rather than load it on the router.