Dear forum users.
CUCM Cluster:- System version: 8.6.2.22900-9
9971 Active Load:- sip9971.9-3-2SR1-1
A very simple problem. If you are using a PC connected to the PC port of a 9971, and you disable the NIC of the connected PC, the audio stream of the call on the phone will cut out and you just get silence. However, if you navigate to Ethernet statistics on the 9971, Rx and Tx frames are still incrementing so the RTP packets are still being presented to the phone. Moreover, if you place the call on hold and then resume it, the audio stream will come back and you can resume the call.
This occurs on both external PSTN calls using a call flow of 9971 - CUCM - H.323 ISR - E1 and an internal call to another IP phone (SCCP 8945). I have tested this on 4 different 9971s and the problem is the same so it is very unlikely to be a hardware fault with the phone. I have also tested on a SCCP 8945 which is the vast majority of handsets in this cluster and the problem does not occur.
Admittedly disabling a NIC on a PC is very rare but what is happening to the customer is they are being told to re-boot their PC by IT support while on the phone to them, and the re-boot of the PC is causing the NIC to disable and thus the audio stream of the call is disconnected.
Has anyone heard of or experienced this issue? I could not find anything similar on CCO bug tool kit. I am pretty sure it will be a 9971 defect but I thought I would throw it out there before logging a TAC case.
