Cisco 8821 sometimes forget Call Manager

[VVVVV80980]

Hi

I have several CIsco 8821 phones at work which sometimes forget the Call manager server. I can see them having Wifi connection on the display yet I can't use the Phone icon.

This is because in settings --> phone information --> device information --> call manager nothing is listed in that moment. When I check back a few minutes later I do see the Call Manager servers listed.

Firmware sip8821.11-0-5SR3-2

WLAN firmware ID 6.50.0.30 (r)

Thansk for any help!

[VVVVV80980]

In the status messages I see 'ethernet disconnected' & 'lasttimecmresettcp' 

Are these useful messages? I really have no idea

[Maren Mahoney]

I have seen various phones throw the "lasttimecmresettcp" error, and it is usually solved with a firmware upgrade. The latest for the 8821 is 11.0(6)SR2. I suggest upgrading one of the affected phones to see if that solves the issue.

Maren

[VVVVV80980]

Thank you for this reply
How can I upgrade 1 phone its firmware? Because we have other sites with this phone and I don't want to mess with their config

Thanks

[Maren Mahoney]

Upgrade IP Phone Firmware Individually 

Let us know if you have any questions!

Maren