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02-09-2012 07:01 PM - edited 03-07-2019 04:50 AM
i have a Cisco phone 7941 connecting to a Cisco 2960 switch port. My voice vlan is 50 and data vlan is 1.
the corresponding switch port settings are:
interface GigabitEthernet1/0/30
switchport mode access
switchport voice vlan 50
no snmp trap link-status
spanning-tree portfast
My PC is hooked in the data port of 7941 phone. It is fine.
The problem is, when the phone is removed, I use the same cable to connect PC to the same wall port hence the same switch port,
the port shows
BNEPSYS-SW09(config-if)#do sh int GigabitEthernet1/0/30
GigabitEthernet1/0/30 is down, line protocol is down (notconnect)
I then remove switchport voice vlan 50 and it means it is in data vlan 1, it still shows the same status.
Does the PC have to connect via IP phone port and it can't connect to switch port directly? what's wrong here?
any advice will be much appreciated.
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02-10-2012 02:38 AM
What is the output of "show vlan"? Is the port showing in Vlan 1? Or it is just "disapeared" all together? On your interface configuration you should always add the data vlan too, manually.
Ex; switchport mode access
switchport access vlan 1
switchport voice vlan 50
You need to shut the port down and asign it to vlan 1 then do no shut. That should
Also check your port security settings, default is 1 MAC per port and that mac is the ip phone. When you plug other device the port goes in error-disable mode and shuts down.
Hope this helps
Eugen
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02-09-2012 07:54 PM
Interesting. The down/down status indicating as if the if the issue is related to connectivity (physical layer). Did you try to connect a laptop directly to the switch port using a regular cable?
Thx
MS
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02-09-2012 08:05 PM
Although I didn't connect laptop directly to the switch port, it is still via wall port, I did change the cable at both ends, I even changed to another switch port, but the status is always down/down. Once I put the phone back, my computer is fine. It really puzzles me!
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02-09-2012 09:04 PM
sorry in turns out the wall ports have problem. I did change to another adjacent port, but that one is faulty as well.
thank you.
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02-09-2012 09:42 PM
Your phone is a 7941 and if I recall correctly, the switch port (phone to PC) is only 10/100BaseTx. This is why it works. When you connect your PC (a 10/100/1000BaseTx) directly it goes down UNTIL you hardcode the switchport to "speed auto 10 100". This is possibly because the last pair of the horizontal cabling is short or not terminated.
You can try to test using TDR.

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02-10-2012 02:38 AM
What is the output of "show vlan"? Is the port showing in Vlan 1? Or it is just "disapeared" all together? On your interface configuration you should always add the data vlan too, manually.
Ex; switchport mode access
switchport access vlan 1
switchport voice vlan 50
You need to shut the port down and asign it to vlan 1 then do no shut. That should
Also check your port security settings, default is 1 MAC per port and that mac is the ip phone. When you plug other device the port goes in error-disable mode and shuts down.
Hope this helps
Eugen
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02-10-2012 05:52 AM
What do you mean with "The problem is, when the phone is removed" Physical removed? removed from the vlan?
Does the PC have to connect via IP phone port and it can't connect to switch port directly? what's wrong here?"
I might be misunderstading the question but it should be like this, you will need 2 utp cables
PC----> dataport --> IP Phone --->Switchport -----> Switch
