Problem with SIP-Trunk

[big-net]

Hello,

since we switched to cisco meraki we have had a problem with our sip-trunk.

Inside our network we have a pbx which set up the sip trunk to our provider.

Mainly at night, if not so much is called the problem appears.

The registration of the sip trunk possibly get lost.

when the PBX registers again with the provider, everything works fine.

Whats the problem?

Any help is appreciated

thanks Oliver

[DarrenOC]

Sounds like the SIP Keepalives are being lost/dropped.

Do you have SIP-OPTIONS enabled as this will frequently talk to the provider to keep the SIP Trunks up?

[big-net]

Thanks for your reply.

Where can i find this option?

We have a MX250.

[DarrenOC]

It’s on your PBX or SBC whichever you’re using to register the SIP trunks 

[big-net]

Yes, but with our old Cisco ASA everything works fine.

The Problem starts since we switched to Meraki.

Nothing has changed on the PBX

[DarrenOC]

Have you run a wireshark trace out of hours on the MX to see what’s happening?

[big-net]

No not yet.

Since I don't know when the effect will occur, I would have to run the wireshark permanently.

i think there is a huge trace file in the end

[PhilipDAth]

Don't use SIP/UDP.  Change to SIP/TLS, and if you cant do that, SIP/TCP.

[big-net]

We are using SIP/TLS.

[big-net]

Hallo,

i have found the following statement about a UDP timeout:

https://documentation.meraki.com/zGeneral_Administration/Tools_and_Troubleshooting/VoIP_on_Cisco_Mer...

The MX does have a simple UDP timer function, which will drop a traffic flow after an extended period of inactivity. This timer cannot currently be changed. However, a timeout would require both peers to be completely silent for an extended period of time in order to take effect. UDP communication between peers on an active call, for example, is highly unlikely to be dropped due to a timeout.

is this may be causing the error?