My clients (Banking Industry) Cisco IP Phone has started to have this ' network unavailable' problem. They have been using this phone for more than a year and I'm afraid more phone will get this kind of problem (currently 3 IP Phone has this problem). I've tested the faulty phone by change the cable, IP address, change to other port, used DHCP or static IP but the phone still not working.
I suspect it's a hardware problem, maybe the network port are burnt. Have anyone encounter this kind of problem, please give your opinion and advice.
** I already full reset the phone too
Solved! Go to Solution.
check for this configuration in CUCM for 7821 phone
Setting up Automatic Port Synchronization
To configure the parameter in the Cisco Unified CM Administration application, choose Device >
Phone, select the appropriate IP Phones, and scroll to the Product Specific Configuration Layout panel
Automatic Port Synchronization
When the Cisco Unified Communication Manager administrator uses the Remote Port Configuration feature to set the speed and duplex function of an IP phone remotely, loss of packets can occur, if one port is slower than the other.
The Automatic Port Synchronization feature synchronizes the ports to the lowest speed among the two ports, which eliminates packet loss. When automatic port synchronization is enabled, it is recommended that both ports be configured for autonegotiate. If one port is enabled for autonegotiate and the other is at a fixed speed, the phone synchronizes to the fixed port speed
Thanks for your reply I'm really appreciate it, but I believe your method is more suitable for unclear voice or unstable connection problem.
But for my problem it seem the IP Phone can't get a connection to the network (status: Network Unavailable) so any firmware upgrade through the server is not possible.
When I replaced the phone with other phone (same model) and connect it to same network port, its working alright. That's is why I suspect it's hardware problem.
What is the exact cucm version and phone firmware version? This will help in checking any known bugs. Also, you might need to capture debugs from the phone and app logs / detaild call manager traces from cucm to investigate the issue as this may be due to an issue specific to your setup.