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4503-E Chassis + WS-X4648-RJ45V+E + 7942G = no power

EDWARD BEHELER
Level 1
Level 1

I ran into an interesting problem yesterday.

WS-C4503-E switch containing a Supervisor 6L-E in slot1 and WS-X4648-RJ45V+E in slots 2 and 3.  A user moved from one office to another and brought her 7942G phone (running SCCP42.9-0-3S) with her to her new office.  When she plugged it in, it would start to boot up, but wouldn't stay powered on for more than a few seconds. 

In troubleshooting the issue, a technician unplugged a working phone from a nearby office on the same switch and got the same behaviour.  When she plugged the originally working phone back in, it also failed to boot up, exhibiting the same symptoms as the other phone.

I discovered that both of these phones were plugged into blade 2.  When I plugged them into blade 3, they both started normally.  Port configurations are identical:

old:

interface GigabitEthernet2/34

switchport access vlan 101

switchport mode access

switchport voice vlan 72

auto qos voip cisco-phone

qos trust device cisco-phone

spanning-tree portfast

end

new:

interface GigabitEthernet3/34

switchport access vlan 101

switchport mode access

switchport voice vlan 72

auto qos voip cisco-phone

qos trust device cisco-phone

spanning-tree portfast

end

I'm not overloaded on power:
show power
Power                                             Fan      Inline
Supply  Model No          Type       Status       Sensor   Status
------  ----------------  ---------  -----------  -------  -------
PS1     PWR-C45-1300ACV   AC 1300W   good         good     good
PS2     none              --         --           --       --

Power supplies needed by system    : 1
Power supplies currently available : 1

Power Summary                      Maximum
(in Watts)              Used     Available
----------------------   ----     ---------
System Power (12V)        444         998
Inline Power (-50V)       302         800
Backplane Power (3.3V)      0           0
----------------------   ----     ---------
Total                     746 (not to exceed Total Maximum Available = 1300)
I'm not sure what to think.  Anyone else had PoE issues with the 4500 series chassis?

5 Replies 5

Reza Sharifi
Hall of Fame
Hall of Fame

When you plug the phones in blade 2, do you see any error being logged on the switch?

Have you run a diganostic on blade 2?

No errors are logged on the switch when phones are plugged into blade 2 (using 'show log'). 

What kind of diagnostic do you mean?

There should be a diagnostic command

diagnostic start module 2 ?

http://www.cisco.com/en/US/docs/switches/lan/catalyst4500/12.2/54sg/command/reference/ch2a_ins.html#wp1537658

Be careful, because some times diagnostic tools are intrusive to the network.

If not, may be reseating the module could be the next step

HTH

Reza

Leo Laohoo
Hall of Fame
Hall of Fame

Plug the phone back in and run a TDR against it.

The commands are:

1.  test cable tdr interface ;

2.  Wait for about 10 seconds and run the next command.

3.  sh cable tdr interface

Please post the result.

dilipratna
Level 1
Level 1

Edward,

We experienced the same issue with a 4506-E switch with a supervisor 6L-E in slot1 and WS-X4648-RJ45V+E in slots 2 and 3.  The issue that we had was with a 7940 VOIP phone.  It would not get power from module 2 but would work fine from module 3, other models of phones such as the 7942G's would work fine in module 2.  All the configurations on the switchports were identical and the phone would also work on another 4506-E with the same IOS and configuration of line cards in module 2?

We resolved our issue by removing the module in slot 2 and re-seating it.  This then was able to power the phone, not too sure as to what the root cause of the issue was but it resolved the problem for us.

Hope this sorts out the issue for you.

Regards,

Dilip Ratna

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