Intermittent one way voice

[Kaushik Ray]

Hello All

I would be grateful to have some advice on this strange thing I am observing.

Users are complaining that there are one way voice sometime and it is quite random and intermittent. Most of the times it is fine but sometime there are issues when the caller is not being able to hear but the called person is able to hear.

The strange thing is that if Site A calls Site B then Site A is not able to hear but site B can hear; again if site B calls then the roles are reversed and Site B cannot hear now but Site A can hear.

Have anyone seen this kind of issues before? and what the potential problems could be

No Dropped packets on Signalling or Calls

call-signaling (match-any)

      23 packets, 1973 bytes

      30 second offered rate 0 bps, drop rate 0 bps

      Match: ip dscp cs3 (24)

        23 packets, 1973 bytes

        30 second rate 0 bps

      Queueing

        Output Queue: Conversation 137

        Bandwidth remaining 2 (%)Max Threshold 64 (packets)

        (pkts matched/bytes matched) 23/1973

        (depth/total drops/no-buffer drops) 0/0/0

voice (match-any)

      2896279 packets, 185361856 bytes

      30 second offered rate 0 bps, drop rate 0 bps

      Match:  dscp ef (46)

        2896280 packets, 185361920 bytes

        30 second rate 0 bps

      Queueing

        Strict Priority

        Output Queue: Conversation 136

        Bandwidth 90 (kbps) Burst 2250 (Bytes)

        (pkts matched/bytes matched) 666835/17346159

        (total drops/bytes drops) 0/0

Anything else that can be tested further ( intemittent nature makes it hard) to isolate the issue?

FYI it is a H323 gateway and the interface bind is already in place.

the interface is configured as

interface FastEthernet0/0.1

description ### LAN - Voice/Mgt ###

encapsulation dot1Q 1 native

ip address xxx.xxx.xxx.xxx 255.255.255.192

no ip redirects

ip tcp adjust-mss 900

h323-gateway voip bind srcaddr xxx.xxx.xxx.xxx

end

[Kaushik Ray]

I found this on the cisco website

I have added it hope it fixes this. but if anyone else can give any insights please advice.

Configure voice rtp send-recv  on the gateway—Sometimes you have one-way audio problems only when  calling specific numbers, such as 411 or 911 in the North American  numbering plan (NANP) or after you transfer a call or put it on hold. If  you are having these problems when going through a Cisco IOS software  voice gateway, be sure that the voice rtp send-recv  command is configured on the gateway. Numbers such as 411 and 911  sometimes do not send back answer supervision (that is, an ISDN connect  message) when the remote end answers. As a result, the Cisco IOS  software voice gateway does not cut through audio in both directions to  prevent toll fraud. Configuring the voice rtp send-recv command forces the voice gateway to cut through audio in both directions immediately

[Kaushik Ray]

Still seeing the same issues after the addition of the voice rtp send receive command.

The main problem is the intermittent nature of the issue; is there any other things that could be tried out in order to attempt to fix this?

please advice

Many thanks

[Sreekanth Narayanan]

Hi Kaushik,

I don't see the h323-voip interface command under the interface.

Also, this is an call between 2 IP phones registered to the different call manager cluster?

Yes, based on what we have seen in the past, you can put in the command and then monitor the setup to see if it worked fine or if the intermittent issue is still there.

Thanks

Sree

[Kaushik Ray]

Thanks Sree for your response; I have added it now

interface FastEthernet0/0.1

description ### LAN - Voice/Mgt ###

encapsulation dot1Q 1 native

ip address xxx.xxx.xxx.xxx 255.255.255.192

no ip redirects

ip tcp adjust-mss 900

h323-gateway voip interface

h323-gateway voip bind srcaddr xxx.xxx.xxx.xxx

end

Yes this is a call between 2 phones between different Call Manager cluster.

I will keep on monitoring.

thanks