PoE+ only getting 100Mbps

[richard.priest]

I have a number of 2700 and 2800 series AP's, connected to a 2960x

All of them without fault will only negotiate to 100Mbps through specific cabling, however if I disable inline power and use a PoE injector, then auto negotiation works perfectly to 1Gbps

If I connect the same AP's direct into the switch via a short lead to the same interfaces, it comes up @ 1Gbps and powered by the switch.

Obviously the fault lies with the cabling, but what I can't work out is why does it work fine with the injector? that blows my mind.

[Scott Fella]

It's because one of the pairs is bad and can't negotiate, so look at how you are patching up the injector and it probably leads to one of the patch cables or rj45 jack.  You can always try a TDR test on the port also or just have the cable tested.  Dirt on the ethernet port or jacks can cause this issue also, so used some canned air and try to connect it back up.

[richard.priest]

Thanks Scott,

I did try the in built TDR on the 2960x, however it didn't turn up anything untoward, all 4 pairs are working fine with no PoE.

I'll try re-terminating the ends, as the crimping tool I used is really poor quality, that sait with a simple cable tester all 8 pins show connectivity.

[Scott Fella]

Keep in mind that all pairs can be fine, but the cable isn’t certified for 1000mbps. Other tools/testers can detect this type of information. You can always connect your laptop to the same cable and see if the laptop negotiates properly but also make sure the ap Ethernet port is bit dirty.

[Leo Laohoo]

If loaded with the correct firmware, 2960X can support TDR.

NOTE: 

• Because there is an injector involved, the TDR will only test up to the injector.  
• In order to test the entire length of the AP, make sure the injector is removed and then test again.