Cisco 7925 Disconnects Intermittently From Network

[mumbles202]

I'm trying to track down the cause of a phone have intermittent disconnects from the network.  It was first reported that at times the phone would just not ring or ring late (only the last ring before going to vm).  Did some initial testing and got the phone replaced but the new phone is doing exactly the same thing.  I deleted the profile from with CUCM and recreated it from scratch but it is still displaying the same behaviour.  Upon further testing I found that a continuous ping to the phone would drop a substantial number of packets when the phone was idle, but as soon as I picked up the phone and went off-hook it was fine.  The same behaviour goes for connection to CUCM (if I make a test call to the phone it doesn't ring, but as soon as I go off-hook from the phone to make an outbound call the initial call begins to display).  I thought maybe this was a bug that just started happening, but the other 7925 in the deployment (same firmware, CP7925G-1.4.3SR1.2.LOADS, is working fine) and has been since they were both rolled out some time ago.  The wireless network is a Cisco WLC based w/ about 9 APs.  Coverage is good and the phone displays good signal strength.  I can literally have the phones next to each other and the problematic phone displays this behaviour while the working phone is fine.  I thought maybe it was a duplicate ip so I tried giving it a known good ip and that didn't help either. 

Anyone have any suggestions of what I can try next?

[migilles]

If you are doing a ping test while the 7925 is in idle mode (not on call) with auto scan mode configured in CUCM for the phone (default setting), then you will see up to 1000 ms ping delay.

Proxy ARP will be advertised when Aironet IE is enabled, which allows the 792x phone to sleep longer vs waking up at DTIM, thus optimizing idle battery life.

If you want to use ping as a quality test tool, then you need to ensure the 7925 is on call.

Is this issue truly only with 1 7925 phone in this same deployment?

If so, how many 7925 phones are deployed?

Need to check upstream signal from the 7925 phone as well, but if outbound calls work fine, then that should be ok unless a roam occurs before the outbound call.

You can enable continuous scan mode as well to help ensure the 792x phone is on the near AP if frequent roaming occurs in this deployment while the phone is in idle mode.

If just 1 7925 phone, ensure that debug is not enabled.  Trace settings for all modules should be set to ERROR level.

Can also factory reset the phone too if you like, which will reset the trace settings.  Simply go to Settings > Phone Settings, enter **2, then select Yes to factory reset.

You are using the recommended 7925 code already 1.4.3SR1.2, but need to check to ensure you are using good WLC code.

I suggest to use 7.2.110.0, 7.3.101.0 or 7.4.100.0.

[mumbles202]

Thanks for the reply.  There are currently 2 7925's, 1 has the issue and the other does not.

I'll have to log in and verify the code on the controller.

[abwahid]

Hi,

Upgrade your WLC to latest code and then try, hopefully it will fix your issue.