7911 Phone with SG300 switch are not registering to CUCM

[ibrahim Adhami]

Dears,

I have 7911 ip phone which are not registering to CUCM once I connected it to SG300 switch when I connect the phone to 2960 switch the phone register normally and works fine.

I already tested another phones like 7975 and 7841 with SG300 switch and they worked fine and were able to register only 7911 phones getting this problem??

CUCM version is 10.5

switch model is SG300-10PP 

Any suggestions would be appreciated.

Many Thanks!

[Nadeem Ahmed]

at what stage the phone is stuck in registering to CUCM? is it showing registering on phone status? what you see in the status message? is it possible to grab pcap/console log from phone and cucm trace.

Br,
nadeem

[ibrahim Adhami]

Hi Nadeem,

I can see the phone is upgrading the firmware and communicating with TFTP but after that nothing happed and it stuck on registring.

Will cpllect the logs and let you know

Thanks!

[ibrahim Adhami]

Dears problem solved, we changed the CUCM name to IP under System > Servers

after that phones were able to register.

Thats strange don't know why 7970 and 7821 were not affected and only 7911 having the issue.

[ibrahim Adhami]

Dears, Issue occurred again :)

After reproducing and testing seems that it's bug behavior on SG300 switch.

in order for 7911 phones to work you must login to switch and apply smartport setting for phone interface and select "Phone+Desktop"

Note that if you disconnect/connect the phone it will stuck in registering again and you would need to login to switch and apply the smartport setting again :(

[ibrahim Adhami]

Dears,

Root cause was related to LLDP on switch we just disabled the LLDP using this command "no lldp run"

Thanks!