Cisco UC560 with IP Phones freezing


I have a UC560 and it has 41 IP Phones connected. There is a mix of SPA502G, SPA525G2, 7921 and 7975.

There is an issue that IP Phones are randomly freezing up and disconnecting etc. and the only way to fix it is to reboot the IP Phone, which isn't a long term solution. It can happen randomly and anytime.

Some IP Phones are PoE on a Cisco Catalyst 2960S and some are using AC adapters connected to other switches. All phones are setup with static IP addresses and are on the main data VLAN (we cannot run separate VLANs unfortunately).

Can anyone help shed some light on what could be causing this and or how to fix it?



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mark_06Author Commented:
Found out this is a bug with the Cisco SPA IP Phones.
Frank MayerTechnical Voip SupportCommented:
well to make a definite answer to this is difficult.
But perhaps i can help you with the procedure to narrow down the culprit here.

First check the log files of the phones or even better enable them to forward messages to a syslog server. Set the log message severity to a higher number if this is possible on your phones. Then make a long term obervation of your network via a span or mirror port. Use wireshark to take a look at that.
If you have way too many packets, then use a trial version from cascade pilot, which you can find on . It allows you to look at rather huge pcap files.
If you have No mirror port available (what a shame ;)), buy a hub or some cheap small switch with mirror port capability and connect a PC (Notebook) and a phone to it. Start a trace which only listens for traffic from and to the phone ! Exclude your own PC to make traces smaller.  If you can´t get some logfiles from the phones or you cant make a network trace you will have no chance to get some idea whats going on.
Check the forums for users which may observe the same issues. perhaps its an enddevice problem which needs to be fixed via a firmware update ?
mark_06Author Commented:
Turned out as Cisco Bug
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