AP negotiating 100Mb instead of 1Gbps

[umeshunited]

Hi All,

Cisco AIR-AP3802I-B-K9 is connected to cisco WS-C4506-E on module WS-X4648-RJ45V+E . WLC is having version as 8.2.166.0 Now the problem is some AP are negotiating 100 Mb even though they are connected to Gig interface of the switch. 

I tried cable testing " test cable-diagnostics tdr interface gigabitEthernet " but it says "%C4K_IOSDIAGMAN-4-TESTNOTSUPPORTEDONMODULE: Online cable diag tdr test is not supported on module"

I also tried configuring speed and duplex on switch manually.

As soon as I try to manually set it , switch port will go down and AP won't come up.

[Scott Fella]

I agree with @Leo Laohoo. One thing to note is that a high end Fluke tester will guarantee the cabling, no matter what.  Also, if you have a laptop connected on the same port and the device connects @1GB then you also have proof that it's not the cabling or the switch.  It's process of elimination, which then points to the access point itself.  I have seen this also, but only a few.  If we see this happen multiple times on the same ap over time, we just RMA the ap and move on.  

[RL5901]

What Fluke tester do you recommend? 

[Scott Fella]

You could always reach out to Fluke and get recommendations.  We have the testers that certify the cabling, but that is expensive.  You can also look at the NetAlly Tools that is for wireless, but can also do some wired testing.  

Put it this way.... there should be no going back a fourth blaming each other.  If a laptop can connect at 1Gbps but the AP at times drop down to 100Mbps, it's the ap.  Maybe you should have the engineer chime in on your post, instead of assuming the issue is with the cable.  I use the TDR test for quick testing on runs with access points, why not.  However, you need to eliminate other variables like possible issue with dirt on the ap ethernet port as an example, replacement of patch cable, etc.  What makes a junior engineer better, is the fact that they keep trying to isolate the issue and eliminate variables.  Keep in mind how the tech test the cable.  They might not test from patch to patch also.  That is why having tools really helps, you or your team can perform different tests.

Connect a laptop to the patch cable the ap is connected to and see.  Or swap out the ap with another ap and see if the issue stays on that cable or moves with the ap.

[Leo Laohoo]

Fluke LinkIQ

Contact the nearest Fluke dealer and they can come in and provide a demo.

[DavidRoss]

Hi all, i have the same problem, i run the TDR test on the switch (9200 poe, ap is C9120AXI) and i have this result. Is the result normal? Obviously the switch is connected to a patch panel that connects to an AP

[Leo Laohoo]

The output is dodgy. 

There are known TDR bugs affecting IOS-XE (CSCwd97177 & CSCvw97924) which renders any output inaccurate, invalid and unreliable.  

Turn off PoE to the port (power inline never), re-run the TDR to the same port and the result should be slightly better.  

[DavidRoss]

Thanks for the reply, i turned off the poe on the interface and this is the result 

[Leo Laohoo]

What firmware is the switch on?

Is that TDR output correct, i. e.  The AP is connected to the port on a 1 metre cable?