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Conference call in preservation mode on cisco 7821 IP Phone.

aniket0422
Level 1
Level 1
Hello All,
We are facing one issue on Cisco 7821 IP Phones. This issue is intermittent. Faced it twice in last few days.
Conference call goes in preservation mode. None of the parties in call can hear, No soft key works. And need to terminate conference call manually.
Phone display shows below messages.
1. Lost server connection - On top of the phone display

2. Conference call in preservation mode - On line-1 button.

 

How to troubleshoot this issue ?

Regards,

Aniket Raut

10 Replies 10

Jaime Valencia
Cisco Employee
Cisco Employee

Is this particular to this phone model only??

You don't mention what's your call control, and version.

HTH

java

if this helps, please rate

Hello Jaime,

Unfortunately customer is having only this model. So not sure if it is model specific.

We are using 10.X

Having a similar issue with 8865.  I just upgraded firmware to the latest 11.5.1 last night on 1 phone having the issue (1 of the very few users that utilizes conference calls).  They've also stated this happens very frequently around the 15 minute mark.

SIP - 10.5

im having this occasional  issue too, so far only 1 user with CP-8845 sip phone. I checked routers,switches no drops/flips. btw phone and CUCM is pptp link 500mb with qos, no congestion, just 60 mb utilized at that time. The " utils core active list" command shows no file. 

Real time sip trace on rtmt shows "cancel" coming from CUCM but i cant open it. Can't collect trace from rtmt for that time, CM has sdl files only for "Today" :( 

Any tips to find root cause  and how to fix trace issue ? 

Bekzod,

In the end it was an issue between our CUBE & CUCM.  I enabled Media Termination Point Required option checked on the SIP Trunk.

We have not had this issue since... plans to upgrade our CUBE this year.

Brian Carlson
Level 4
Level 4

You're most likely facing a network connectivity issue between the phone and CUCM that's causing it to go into SRST mode.

If the phone crosses a WAN to reach CUCM, check the QoS configuration and bandwidth utilization on the WAN circuit. If the phone has LAN connectivity to CUCM, check the LAN QoS.

 

It's also a good idea to upgrade to the latest firmware available for your phone model.

Hello brian,

Is there any way to find out network connectivity issue. Can we collect any logs from RTMT to prove same.

And we are not using SRST.

Hi,

 

This message means that phones lost connectivity to call control server (CUCM or CME) during conference call. In this is the case and you don't have SRST, then softkeys won't work and call won't be terminated by call control server (for the call to be terminated, you need to enable media-inactivity detection).

 

Are these phones remote to call control or same LAN?

How to enable media inactivity detection ?

What will happend if i enable this ?

Call Manager belong to 192.168.58.x

IP phones belong to 192.168.60.X

Are these two subnets connected over WAN? May be you need to check your WAN and the reason for connectivity drop.

 

Regarding media-inactivity detection (note this will impact preserved and non-preserved calls. In h323 you can limit this feature to preserved calls only):

 

    RTR(config)#gateway
    RTR(config-gateway)#media-inactivity-criteria ?
      all     Both RTP and RTCP for silence detection
      rtcp    Use RTCP for silence detection
      rtp     Use RTP stream for silence detection, this is default
      rtplib  Use RTP ( comfort noise = activity) for silence detection
  

This feature is controlled by two commands which are ip rtcp report interval global command and the timer receive-rtcp gateway-level command. The multiplication of both commands will generate inactivity timer.

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