Re: voice only heard in one direction

j.butterfield · ‎05-18-2001

I have a 2600 with a FXO port in it. I can dial into the port from the PSTN and get to an 7960 phone. The call gets established but the IP phone cannot hear the person calling on the FXO line, but the person on FXO line can hear the IP phone user. What's up with that? I suspect a codec issue, but I believe both the 2600 and CCM are using g711. Also the fxo line can dial extensions once voicemail picks up so some info is getting through, just not the voice.

Thanks in advance

mgardiner · ‎05-21-2001

This may help - David Goodwin posted it to another question "voip dial peer ip address "

Mar 13, 2001, 11:21am Pacific (1.)

You are correct in your concerns. If the endpoint of the RTP stream is out a different interface on the router, than the H.323 signaling and the RTP stream can originate from different IP addresses, causing one-way audio in most cirsumstances.

The best way to solve this problem is by using a Loopback interface, and using a command introduced in 12.1(2)T that will cause all H.323 signaling and RTP streams to source from this address. Then point your CallManager H.323 gateway config to this address. Example:

interface Loopback0

ip address 10.1.1.1 255.255.255.0

h323-gateway voip bind srcaddr 10.1.1.1

j.butterfield · ‎05-22-2001

Actually, this answer doesn't seem to apply to my situation. I am controlling the gateway (2600) through mgcp using call manager. I am not using h323 in any way that I know of.

dgoodwin · ‎05-22-2001

Look at show run and make sure that you have not configured no ip routing. If you see it there, turn it back on.

j.butterfield · ‎05-24-2001

tried that, but no worky :)

uttaranc · ‎05-22-2001

I was having the same problem with vg-200.I turned on ip routing and solves the problem.

ip routing global command.

j.butterfield · ‎05-24-2001

That doesn't seem to be my problem. Ip routing is turned on.

Brian Carscadden · ‎05-25-2001

I've had a few instances with one-way communication. The most common source was related to routing or addressing. I would check your addressing end-to-end. Show your IP routes and ping everything. A recent issue related to an incorrect subnet mask (typo) on an ICS 7750. I've had the mismatched codec issue be the source - just to be sure issue the codec command on the router - even if the tech docs say it's g.711 by default. Incidentally, you can tell the codec used on a call by pressing the "I"nformation button twice on the 7960.

Good luck,

Brian Carscadden

Sr. System Engineer

CCNA, CCDA, CIPT

TransNet Corporation

j.butterfield · ‎05-30-2001

I checked the phone and both the transmit & receive say g7.11u Also, everything is on the same subnet and everything is pingable from a remote subnet, so IP communication seems to be working.

Here is something weird. I changed the codec to g723ar53 and hey what do you know it works! Even though the phone says that both are using g7.11u? Go figure. I need to do more testing to see why it works when I apparently select the wrong codec, but the bottom line is that it appears to be a codec issue.

d-case · ‎05-25-2001

Had a simillar issue, needed to upgrade the IOS 12.1.5T8 seems to work for us

j.butterfield · ‎05-30-2001

Well, we are already at 12.2.1 :)

brian.faulkner · ‎05-29-2001

Try the global config command 'voice rtp send-recv'

j.butterfield · ‎05-30-2001

Thanks, but no luck.

fpizano · ‎05-30-2001

Please make sure that you have enabled the following commands in your global config:

voice rtp send-recv

ip routing

Francisco.-

j.butterfield · ‎05-30-2001

Ip routing is enabled. It doesn't seem to matter if I have the voice rtp send-recv command or not. I tried the g723ar53 codec and that seems to work for some reason. Even though the phone says that both tx & rx are g7.11u?