Cisco 7911G Phone and Speed/Duplex trouble

[petterjoh]

Hello all !

We have rolled out a quite large number of Cisco IP-Phones in a CCM4 environment with only Cisco network equipment.

Lately ive seen a disturbing problem popping up around the network, that is the phones coming up with 10mbit half-duplex connections (this is a problem because we have computers behind the phones)

a sh int status command will generally display many of theese lines:
Fa0/5 Vlan connected xxx a-half a-10 10/100BaseTX
Fa0/6 Vlan connected xxx a-half a-10 10/100BaseTX
-------------------------------------------------------
A show interface fa0/5 command will f.ex display this output

FastEthernet0/5 is up, line protocol is up (connected)
Hardware is Fast Ethernet, address is 0018.738d.5387 (bia 0018.738d.5387)
Description: xxx Vlan
MTU 1500 bytes, BW 10000 Kbit, DLY 1000 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation ARPA, loopback not set
Keepalive set (10 sec)
Half-duplex, 10Mb/s, media type is 10/100BaseTX
input flow-control is off, output flow-control is unsupported
ARP type: ARPA, ARP Timeout 04:00:00
Last input never, output 00:00:00, output hang never
Last clearing of "show interface" counters never
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: fifo
Output queue: 0/40 (size/max)
5 minute input rate 0 bits/sec, 0 packets/sec
5 minute output rate 0 bits/sec, 0 packets/sec
504628 packets input, 33262781 bytes, 0 no buffer
Received 378841 broadcasts (0 multicast)
0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
0 watchdog, 378748 multicast, 0 pause input
0 input packets with dribble condition detected
28367777 packets output, 2405741534 bytes, 0 underruns
0 output errors, 8 collisions, 1 interface resets
0 babbles, 0 late collision, 0 deferred
0 lost carrier, 0 no carrier, 0 PAUSE output
0 output buffer failures, 0 output buffers swapped out

----------------------------------------------------------
Configuration for the example port fa0/5 is like this:
(same as all other port configs)

interface FastEthernet0/5
description Accessvlan + Voicevlan
switchport access vlan xxx
switchport mode access
switchport voice vlan xxx
srr-queue bandwidth share 10 10 60 20
srr-queue bandwidth shape 10 0 0 0
mls qos trust device cisco-phone
mls qos trust cos
auto qos voip cisco-phone
spanning-tree portfast
end

Been searching theese forums and cisco TAC for other with the same problem, but cant see anything.
The phones that we are experiencing this problem with is the 7911G phones. Would appriciate any help/tips on this case

With Kind Regards.
Petter Johnsen

 

[ADB100]

The 7911G definiately supports 10/100 Auto operation so should by default negotiate 100/Full with your Cisco switch (looks like either 2960, 3560 or 3750?). Have you tried bypassing your infrastructure cabling and connecting the phone direct to the switch?

I had a quick look on CCO but can't see anything obvious, that doesn't mean there isn't a bug. What phone firmware are you running?

HTH

Andy

 

[whykap]

What type of switches are you connecting to? would it happen to be 45xx by any chance?
Did you try hardcoding the phone to 100 full on the phone itself?

 

[ADB100]

The switch is either a 2960, 2970, 3560 or 3750 due to the 'srr-queue' commands. Hard-coding isn't the answer, however it might be a firmware issue with the phones.
I would suggest you download the latest firmware and install it (via CCM or manually if you are using SIP).

HTH

Andy

 

[petterjoh]

Hi and thanks for your replies. (its a while, i know )

The switches used are 2960, 2970 & 3560's
all switches shows the same error (randomly)
80% of the switches are 3560G 24/48port PoE switches.

Tried upgradeing phone firmware to the newest version in the start of January (dont have the version number where i am now, so cant say)
This change had little to no effect.

Still monitoring the problem though. Going to try creating a Cisco TAC Case


(i have not hardcoded the switchport to 100/1000 full duplex since i want it to be auto)

 

[petterjoh]

Forgot to mention that all cabling has been Cat6 verified by a outside company, so i have trusted their testing, havent tried phones directly on the switched (allthough it might be time to do so.)

I corrected all the 10/half ports by doing shut / no shut, and didnt see the problem again for some time.

im suspecting that the problem my come from power shortages where the phoneport is up before the switchport is, and that might be causing problem. But this is just a theory.

allthough i can say for sure that not every 10/half case has arrived after a power outage.

-Petter

 

[DallasBPF]

well first off.. the phone should not get power until the switch see's that it is a phone via CDP... so I doubt that would be your issue... I would try hard coding your switches to 100/full with the range command.

Dallas, Texas
Telecommunications
CCNA, Net+
Working on MCSA, Convergence+, CCVP

 

[ADB100]

well first off.. the phone should not get power until the switch see's that it is a phone via CDP... so I doubt that would be your issue... I would try hard coding your switches to 100/full with the range command.

Don't hard-code the switches..... If you have read anything on here it is don't hard-code anything at one end without doing the other end as it will result in duplex mis-matches (assuming you hard-code full-duplex). I suggest you try connecting the phones directly to the switch and bypass your infrastructure cabling. If you are using power bricks on any phones try powering these up first and then connecting them to the switch to see if that has an effect. It may be worth also leaving a phone powered up and reloading a switch to see if that affects it.

Andy