1252 Wired Interface not negotiating highest speed

Unanswered Question

Hi,

I have 2 1252 APs (A & B)

A is the model with only BG radio module

B has both BG and A radio modules

I have them plugged into an unmanaged gigabit switch. AP A has negotiated 1000Mb/s on the wired interface (GigabitEthernet0) but AP B will not step up to 1000Mb/s from 100Mb/s. This seems very odd. I have swapped the ports to which they are connected with no change.

Is there a way to tell the AP to re-negotiate the link?

Here below are the results from a 'show interface GigabitEthernet0' on each AP:

A:

GigabitEthernet0 is up, line protocol is up

Hardware is PowerPC 8349 Ethernet, address is 0023.3339.a4ca (bia 0023.3339.a4ca)

MTU 1500 bytes, BW 1000000 Kbit, DLY 10 usec,

reliability 255/255, txload 1/255, rxload 1/255

Encapsulation ARPA, loopback not set

Full-duplex, 1000Mb/s, media type is T

output flow-control is unsupported, input flow-control is unsupported

ARP type: ARPA, ARP Timeout 04:00:00

Last input 00:00:00, output 00:00:00, output hang never

Last clearing of "show interface" counters never

Input queue: 0/1677/0/0 (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

2767 packets input, 450861 bytes, 0 no buffer

Received 1489 broadcasts, 0 runts, 0 giants, 0 throttles

0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored

0 watchdog, 0 multicast, 0 pause input

0 input packets with dribble condition detected

2031 packets output, 1667621 bytes, 0 underruns

0 output errors, 0 collisions, 2 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

B:

GigabitEthernet0 is up, line protocol is up

Hardware is PowerPC 8349 Ethernet, address is 0024.9752.678e (bia 0024.9752.678e)

MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec,

reliability 255/255, txload 1/255, rxload 1/255

Encapsulation ARPA, loopback not set

Full-duplex, 100Mb/s, media type is T

output flow-control is unsupported, input flow-control is unsupported

ARP type: ARPA, ARP Timeout 04:00:00

Last input 00:00:03, output 00:00:11, output hang never

Last clearing of "show interface" counters never

Input queue: 0/1677/0/0 (size/max/drops/flushes); Total output drops: 0

Queueing strategy: fifo

Output queue: 0/40 (size/max)

5 minute input rate 2000 bits/sec, 1 packets/sec

5 minute output rate 0 bits/sec, 0 packets/sec

980 packets input, 101479 bytes, 0 no buffer

Received 934 broadcasts, 0 runts, 0 giants, 0 throttles

0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored

0 watchdog, 0 multicast, 0 pause input

0 input packets with dribble condition detected

95 packets output, 11120 bytes, 0 underruns

0 output errors, 0 collisions, 2 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

Any Ideas?

TIA

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xcz504d1114 Fri, 03/06/2009 - 12:35

Whats the output of a "show run int gi 0" on B?

Autonegotiation continuously happens, so there is nothing you need to do to "force" speed negotiation, even when you hard set the port speed and duplex, speed negotiation information is still transmitted (duplex information is not).

Gigabit ethernet uses similar technology to the FLP (Fast Link Pulse) to determin port speed, 100 Mb ethernet also uses an FLP but only for copper, 100 Mb fiber uses a different signaling scheme. Specifics can be found in the 802.3z (Clause 37) for gigabit ethernet.

Leo Laohoo Fri, 03/06/2009 - 16:09

How are you providing power to the 1250? Power Injector, Standard PoE or enhanced PoE?

Have you tried removing one of the radio modules?

Are both 1250 running the same IOS?

Have you tried to force the speed?

glen.grant Fri, 03/06/2009 - 17:43

You probably have a faulty patch or drop wire somewhere . Gigabit requires all 8 wires in the run to be good as gigabit uses all 8 wires .

Both are running the same IOS

I have tried to force the speed, but it just shuts down the interface altogether.

Not sure what removing a radio module would do.

Using the exact same patch lead to connect A and then B, I achieve 1000Mb/s on A, but on B, it the interface reports just 100Mb/s.

Is it possible that it is a problem with the port on the acecss point itself? I just received this AP but would be happy to RMA it if this can be tested/confirmed?

Leo Laohoo Sat, 03/07/2009 - 15:07

Q: Not sure what removing a radio module would do.

A: In order to answer this question, you need to let us know how are you providing power to the 1250? Power Injector, Standard PoE or enhanced PoE?

If you are using enhanced PoE or Power Injector then this is not required.

Leo Laohoo Sat, 03/07/2009 - 23:08

Thanks Charlie. Did you say power "transformer"? Is is a power brick or a power injector? Where did you get this power "transformer"?

I'm not sure if you're aware of this but, when using a Autonomouse IOS the 1250 AP requires a minimum of 18.5 watts of power to be able to operate both radios. When being fed with 15.4 watts of power, the AP will shut down both of the radios and the interface might operate at 100mbps.

However, if you have a WLC (5.2.X FW), the 1250 will be able to operate both radios even when powered using 18.5 watts.

The power brick is from cisco & is the one for this ap.

I am aware of the power requirements for the ap.

It seems that the radios are not the problem, rather it is the core part of the AP that is the problem.

This core (excuse my terms I dont know what else to call it) is defective. I have switched everything from A to B and back again. Im assuming that the Ethernet port is defective. How do I initiate an RMA? With cisco directly or the place where I purchased?

TIA

sbeallan Sat, 03/28/2009 - 13:00

Charlie,

I hope the RMA resolves your problem. I have an issue with identical symptoms, but in my case the problem is not the AP itself, it's the PoE power injector (AIR-PWRINJ4).

I tested the cable run and the patch cables and they were fine if tested on their own. When I plug two patch cables into the AIR-PWRINJ4 and test THROUGH it only 4 of the 8 wires are in use and the other 4 test bad. With only 4 wires active, the AP and switch port will not negotiate 1 Gbps and fall back to 100 Mbps.

I was unclear from your post whether or not you're using a power injector (AIR-PWRINJ4) or the power supply (AIR-PWR-SPLY1). If you're using the power injector and the RMA doesn't fix your problem you might try a new power injector or a different method of powering the AP.

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