IP Communicator Network Issues 3

[Misadventure]

Hi all,

We are seeing a problem with an initial test deployment of IP Communicator SoftPhones in that the network is configured for a Voice VLAN and a Data VLAN and with Handsets this works correctly.

However when you install a SoftPhone, the PC boots normally and is on the Data VLAN, but when the SoftPhone is initialised, it switches to the Voice VLAN, effectively stopping the user from accessing other network resources.

Has anyone seen this? Our 3rd party company has recommended just having one VLAN for both Voice and Data for SoftPhone users and/or disabling CDP but my gut is telling me that both of these 'options' aren't correct...

Any help/recommendations would be appreciated!

 

[ADB100]

I came across this a while ago with some Catalyst 4500's and logged a TAC case with Cisco. The engineer confirmed the behaviour and said it was a bug. I can't look at the moment what BugID was assigned to it, but the workaround was to disable CDP on the port as it was this that was causing the issue.
When IP Communicator was launched on the PC it started a CDP driver which transmitted CDP packets that the switch saw. Cisco changed the IOS so that only two MAC addresses were needed on a Voice/Data port (for port-security) where previously three were needed - the logic was two for the IP Phone; one on the Voice VLAN and one on the Data VLAN, plus one for the PC. The code changed this so as soon as CDP was seen from the IP Phone it removed the PC's MAC from the Data VLAN CAM table and added it to the Voice VLAN CAM table.
The workaround was to either disable CDP on the switchport or disable it on the PC.

HTH

Andy

 

[jeter]

Odd I never had any of these issues with the ip communicator... The only issues we have had are firewall or routes back to the network...


SPC NVARNG
Tek-TIP Member 19,650

 

[whykap]

I feel good about this. A bug I haven't had to deal with......

 

[ADB100]

Odd I never had any of these issues with the ip communicator...

I think it was due to a combination of settings applied to the user access ports. Each port was configured as follows(minus the QoS configuration):

interface range fastethernet 3/1 - 48
 switchport access vlan 10
 switchport voice vlan 100
 switchport port-security maximum 3
 switchport port-security
 switchport port-security violation restrict
 switchport port-security aging type inactivity
 switchport port-security aging time 2
 ip dhcp snooping limit rate 100

This was on Catalyst 4500's and worked with IOS 12.2(25)SG, however we upgraded to 12.2(31)SG and hit the problem with IP Communicator. Re-reading through my notes it looks like this was an issue with the port-security code. In 12.2(31)SG as soon as CDP was seen from a Cisco IP Phone the MAC address of the phone was immediately removed from the CAM table for the access VLAN. This then allowed you to restrict port-security to two MAC addresses per access port (one for the IP Phone and one for the PC). This was obviously not an issue for the IP Phone. However the code did the same for the PC when it started the CDP driver.
The workaround was either to disable the CDP driver on the PC or disable port-security. I am not sure if this has ever been fixed?

HTH

Andy

 

[JB206]

thanks for the help, i am experiencing the same issue, bug CSCsm26277 seems to be it