Limit call duration or support RFC4028 in SPA112

[startrinity]

Hello, our company StarTrinity.com would like to use thousands of Cisco SPA112 ATA devices to customer's monitor IP networks between client and cloud IP PBX, using media loopback (see https://supportforums.cisco.com/t5/atas-gateways-and-accessories/spa-122-loopback-capabilities/td-p/2450922 ). Our server software makes continuous 1-minute test calls to registered cisco ATA in media loopback mode. 

We faced a problem: when internet connection breaks for few minutes, Cisco ATA gets busy with hang call, and further calls get rejected with 486 (busy here).

Is there way to limit duration of hang calls in cisco SPA112  or support RFC 4028 (session timers), so hang calls will not break our continuous network tests?

[Dan Lukes]

Did you considered to use TCP instead of UDP ? I didn't tried it by self - it may or may not work better for you.

By the way, even 486 response confirms the remote IP network is reachable.

[startrinity]

Thanks for quick reply, we will try TCP, good idea. Yes the 486 response is good but we need to measure packet loss and jitter continuously, not just "request-response time".   Is there other way besides SIP/TCP?   Session timer or just "max call duration" in SPA112?

[startrinity]

Should I expect reply here?

[startrinity]

We have tried TCP transport. It did not help. The calls remain in hang state, and it looks like Cisco ATA does not send any keep-alive packets to make sure that current SIP call is still alive.

How can we avoid hang calls in SPA 112/SPA122?

[Dan Lukes]

You can't as far as I know.

I guess media loopback has been implemented for debugging purposes. Moreover, SPA112 has been designed for reliable connections between it and PBX. You are trying to use it outside of expected use cases.

Note I'm just volunteer. If you wish for authoritative answer, buy support pack and call SMB Support center. You can request new features as well. But don't put so much hope to it. There are not so much success stories known with SMB Support. Not counting trivial questions ...

[Daniele Giordano]

Hi, unfortunately SPA 112 or 122 do not support session timer and there is no cut off function on board.

Regards.