Issues with cable modem (vs fiber or DSL connection)

[carnea]

Hello !

We have a new 3CX server on premises since 5-6 months. We have always experienced registration issues : about once a week the server looses the connection with the sip trunk. Our sip trunk provider as well as our IT supporter think the cable modem connection is the culprit (UPC Cablecom in Switzerland, DOCSIS 3.0). They say that the cable modem can produce micro cuts (that wouldn't happen on a fiber or DSL connection). We changed the cable modem for an (older) Hitron CGNV4) to no avail. Our IT supporter is sure that our LAN is not the cause of the issue.

Is it know that VOIP doesn't run well on a cable modem ? Or some kind of cable network ?

Do you know of a solution to avoid these registration problems ?

Thank you !

Thierry

 

[YiannisH_3CX]

Hi @carnea

Is it know that VOIP doesn't run well on a cable modem ? Or some kind of cable network ?

Do you know of a solution to avoid these registration problems ?

That would depend on your type of trunk. Micro cuts would not affect a UDP based trunk as the trunk is registered until the registration expires. The server will try to refresh the registration long before it expires and it will try multiple times before the registration expires. So a micro cut would not cause these issue, at least not repeatedly.
If the trunk is TCP based and every time the connection cuts out the TCP connection gets reset then yes that would cause issues and a more stable connection would solve your issue.

However this is all theoretical and the best way to solve this is by pinpointing the issue by doing packet captures on the network to see what is causing the deregistration of the trunk. Intermittent issues like these are hard to troubleshoot because they happen at random times but you could use tshark to continuously capture traffic on the 3CX server without running out of disk or memory. Once the issue occurs then you could stop the capture and look at the files to find the issue.

 

[carnea]

Hello Yiannis !
Many thanks for you quick answer. I'll look into it with our trunk supplier and with our IT...

 

[YiannisH_3CX]

Let us know what you find.