VoIP: I'm heard but I can't hear

RouterOS General
1

Hi

We are currently replacing Cisco ASA 5505 routers on a client’s sites with RB951G-2Hnd
Data communications are all transmitting properly

The issue is with VoIP : when we call another site we can hear, but we cannot be heard
We hear a minute snippet of sound at the very beginning, then nothing

I have forwarding rules to allow 5060 (udp) SIP, 1000-12000 (udp) RTP, and 8667 (tcp) provisionning

If we call another site that is still equipped with one of the previous Cisco 5505 routers the conversation works both ways.
If that same remote site, equipped with the Cisco 5505, calls the site using the RB951G then same issue: we can hear but cannot be heard.

We disabled the SIP service helper very early on because we discovered that only one telephone on the site could make calls (register) => NAT issue; so that works properly now.

But I don’t understand what could be blocking the call response - also I’m not very experienced with VoIP

I tried disabling my firewall filters but the situation is the same

Any one seen this issue before ?

Thanks
yann

2

Try to sniff Call with packet sniffer and analayze with wireshark voip call analayzer…

3

Thanks Kickoleg

I ran Wireshark and asked the users to call each other
Now I have to sift though >16000 lines - thank goodness for filters !

Apparently there are a number of “wrong sequence nr.”

With SIP there are a bigger percentage of 4xx errors (210x401 and 200x404) compared to successes (200)
With RTP, there is also a high level of “lost”: varies between 87% and 100% (not sure how to read this indicator

Will keep digging to try and understand what all this means

yann

4

My comms problem was linked to incomplete firewall rules.
Fixed, thanks

5

i know this is very old thread..

but i experience the same problem. I both have yealink and cisco ip phone. i got no problem with the yealink but cisco is a special case.
they can hear me but i cant hear them.

tried to sniff, direction only tx,