AIR-AP3502i gigabit interface issue

Unanswered Question
May 7th, 2012

Support Community,

          I currently have an issue with my AIR-AP3502i gigabit interface. I connect my AIR-AP3502i to my 3560G POE switch and the port will not negotiate to1GB. I have tried auto negotiate and hard coded settings but when I try those settings the switch and AP interfaces go into an up down state. Has anyone seen this issue before?                   

I have this problem too.
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shh5455 Mon, 05/07/2012 - 13:51

That sounds like a cable problem to me.  Plug the AP directly into the switch with a new cable and see if it is still an issue.

lmecarrasq Mon, 05/07/2012 - 21:10

Tried a different cable and different port switch, still same issue, it only negotiates at 100MB full.

Leo Laohoo Mon, 05/07/2012 - 15:18
I currently have an issue with my AIR-AP3502i gigabit interface. I connect my AIR-AP3502i to my 3560G POE switch and the port will not negotiate to1GB. I have tried auto negotiate and hard coded settings but when I try those settings the switch and AP interfaces go into an up down state. Has anyone seen this issue before? 

I've seen and heard of this sob story before.

This is most likely caused by a faulty cable or the cable run, particularly the pair that supports 1 Gbps (fourth pair).  One way to isolate and determine if this is the case is to run a TDR

The good part is you have a 3560G so this appliance will support TDR.  Here are the command combinations:

1.  Command:  test cable tdr interface ;

2.  Wait for about 7 to 10 seconds (3560 takes longer than a 2960/3750);

3.  Command:  sh cable tdr interface ;  and

4.  Kindly post the output.

lmecarrasq Mon, 05/07/2012 - 21:18

My IOS appears to not have that command option. Is that in a specific switch IOS version.

Leo Laohoo Mon, 05/07/2012 - 21:19
My IOS appears to not have that command option. Is that in a specific switch IOS version.

Can you please post the full output to the command "sh version" please?

lmecarrasq Mon, 05/07/2012 - 21:50

Never mind, I was mistaken, the command was there. Thanks for the new command.

Interface Speed Local pair Pair length        Remote pair Pair status

--------- ----- ---------- ------------------ ----------- --------------------

Gi0/7     100M  Pair A     0    +/- 4  meters Pair A      Normal             

                Pair B     132  +/- 4  meters Pair B      Fail               

                Pair C     110  +/- 4  meters Pair C      Fail               

                Pair D     1    +/- 4  meters Pair D      Normal            

Interface Speed Local pair Pair length        Remote pair Pair status

--------- ----- ---------- ------------------ ----------- --------------------

Gi0/7     100M  Pair A     0    +/- 4  meters Pair A      Normal             

                Pair B     132  +/- 4  meters Pair B      Fail               

                Pair C     110  +/- 4  meters Pair C      Fail               

                Pair D     1    +/- 4  meters Pair D      Normal             

Leo Laohoo Mon, 05/07/2012 - 22:38

Please forgive me for this comment:  WTF!  Wow!  That's one lousy TDR result.

lmecarrasq Tue, 05/08/2012 - 07:03

It is only a patch cable and not an actual cable run. As yo ucan see in a previous reply. I tried another patch cable and a different switch port.

Leo Laohoo Tue, 05/08/2012 - 16:21
It is only a patch cable and not an actual cable run. As yo ucan see in a previous reply. I tried another patch cable and a different switch port.

Please test the entire run (from the switch to the WAP).

The two results you've posted are the same but as I can see this it won't work.  Pair C controls the PoE.  Pair B controls OSI Layer 2.

It's also telling me that the switchport is detecting Pair D (controls GigabitEthernet) at only 1 metre.

Moral Lesson:  The output is showing me that your cable directly connected to the switchport is manually spliced-n-diced (not machine manufactured) and someone did a poor job at it. 

lmecarrasq Wed, 05/09/2012 - 06:50

The issue was the patch cable, however these were not man made patch cables. These must have been a bad batch of cables.

Thanks for your help and the new command to use.

Leo Laohoo Wed, 05/09/2012 - 15:57
The issue was the patch cable, however these were not man made patch cables. These must have been a bad batch of cables.

Cool!  Glad to see it's working. 

Leo Laohoo Mon, 05/07/2012 - 22:37

Thanks Blake. 

Just want to remind you that I would not recommend using TDR on a Catalyst 4500 or 6500.  Works very well if you have 2960/2960G/2960S, 3560G/3560E/3560X and 3750G/3750E/3750X.

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