Our main office in UK has Cisco CCM version 5.1.
The branch office in India has Avaya PBX.
Both the systems are trunked via H.323.
The Avaya PBX has a media processor card that acts as a H.323 gateway.
The RTP traffic from the IP Phones in UK flow via the MPLS network and reach the Avaya media processor card on the avaya gateway where it is converted into analog and then on passed to the analog phones with the Avaya PBX.
IP phone users in UK are not having any issues and they can hear the Indian analog phone users perfectly.
The India users are complaining of quality of voice issues. They are complaining that occasionally there is a white noise for a brief duration of 5-10 seconds that masks the voice.
Silence suppression is disabled on the avaya gateway.
We also have a few Cisco IP Phones in India.
IP Phone users in India have no QoS issues when talking to IP Phones users in UK.
Interestingly, the avaya analog phone users in India have no issues when talking to IP phones users in India.
Avaya analog phone users have the QoS issue only when talking to IP Phone users in UK.
We are really struck with this issue.
We will be very thankful if you could help us fix this issue.
Many Thanks in advance