sip phone loss the voice

[ahmed]

Hi all,

i have cme and SIP phone 7821, there is problem the phone will loss the voice when two side (2 phones) doesn't talk for awhile then there is no voice like nobody talking, i look into the connection is fine, please anyone know the cause.

regards,

ahmad

[Manish Gogna]

Hi Ahmad,

Can you check if VAD is disabled on the dial peers. With VAD, voice data packets fall into three categories: speech, silence, and unknown. Speech and unknown packets are sent over the network; silence packets are discarded. The sound quality is slightly degraded with VAD, but the connection monopolizes much less bandwidth. If you use the no form of this command, VAD is disabled and voice data is continuously sent to the IP backbone.

http://www.cisco.com/en/US/docs/ios/12_3t/voice/command/reference/vrht_v1_ps5207_TSD_Products_Command_Reference_Chapter.html#wp1103127

Manish

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[ahmed]

hi manish,

thanks for reply, the phone will no audio for some particular number (external call), and for other number going well any idea about that?

Regards,

ahmad

[Manish Gogna]

Hi Ahmad,

Is it "no audio" or "intermittent silence" that you are experiencing? For no audio it can be a routing / firewall issue , whereas the silence between the calls is attributed to vad being enabled on dial-peers. From your last post it looks to be a no audio / one-way audio issue. To begin with you can get "debug ccsip messages" from the same ip phone for a working and non-working call so that the signaling can be compared.

Manish

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