cisco phone and PC not registering on specific ports

[chris57]

Hi, I have a problem with a cisco WS-C3850-48P, where I have had to move users to switchports in the second cluster of 24 ports to get them working. Although there are users quite happily working in the first 24 port cluster, there is a group of 4 ports which appear to have no problems, have the same config, but a cisco phone nor a PC will get a connection. 

The phone will not register, even though I can see it's mac address connected to the switch port. And yet if I move the phone onto the second cluster of 24 ports, it comes straight up.

I have investigated to suspect ports, and I can't find any reason this is happening. I have tried bouncing the ports. There are no errors on the interface. They have the same config. The ports look ok but quite clearly there is something wrong. Any help or suggestions would be appreciated.

Regards

Chris57

[Deepak Kumar]

Hi,

did you check with removing the phone from these port and connect directly to PC?

I think first you have to check to remove the Phones, POE budge available and used Power budge, Phone POE requirement, Cable etc.

The second section will come with switch port, set default to the port and reconfigure the port. And share switch port status on the post.

Regards,

Deepak Kumar

[chris57]

Ok not quite sure what you mean, but I have a phone in a suspect port which works straight away in a port in the second cluster, so i know the phone works. And I can see it's mac address on the suspect port. Just wont register. Nor a PC will not get a network connection

[chris57]

I have been trawling through the cisco show commands trying to find any difference between the working against the non working ports, and I cannot find anything. But there must be something. The only thing I can say so far is that all of the non working ports are on the first cluster of 24 ports.

[Deepak Kumar]

Hi,

Are there any logs? 

I suspect about configuration issue or a bad switch.

Just run below command:

default interface gig<x/x/x>

Inter gig <x/x/x>

switchport mode access

switchport access vlan <x> ! Data vlan number

and try to connect your laptop with direct patchcord. Don't use any existing patch panel or cable. 

If there will no result then book a case with TAC.

Regards,

Deepak Kumar

[chris57]

No significant logs. Laptop works, as phone also works in other ports. All configured the same. Access to the same vlans.

[Deepak Kumar]

Hi,

Share the running configuration and show mac address table interface gig <>

Regards,

Deepak Kumar

[Leo Laohoo]

Post the complete output to the following commands: 

1.  sh version; 

2.  sh interface <BLAH> controll

[chris57]

The phone's MAC address appears as a CDP neigbour and shows connected on the port. The port itself is configured exactly the same as a working port.

[chris57]

OK this has got a little more interesting.

I reloaded the switch and now the phone has registered.

So a reload has cured the problem, as expected, but this is a little drastic, as the Network I look after, very sensitive and downtime is not easily achieved.

So I am looking for a way to reset the individual ports without reloading the whole box. A simple shut/no shut is not enough.

Any suggestions please.

Regards

Chris