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Super Bronze

3750 with Avaya PoE problems

Hi

Anyone using 3750s with Avaya telephony?

We've had some odd reports recently...

Phones occasionally losing power. Swapping the phone doesn't help - the only way to bring power back is to either shut/no shut the interface, or connect a non-PoE device to the switch, then put the phone back.

We've not established a pattern yet, it seems random.

One thing I've noticed is that when it happens, that port on the switch indicates a Class 0 (15.4w) device, whereas the other phones indicate Class 2. Clearing that port results in renegotiation at Class 2. Perhaps it's a generic problem with af devices? Or a phone firmware problem?

Aaron

Aaron Please remember to rate helpful posts to identify useful responses, and mark 'Answered' if appropriate!
5 REPLIES
Bronze

Re: 3750 with Avaya PoE problems

I have a ton of avaya phones running on 3750 and never experienced that type of problem. I would make sure phone are at avaya 2.3 firmware release and open up a ticket with cisco TAC.

Super Bronze

Re: 3750 with Avaya PoE problems

Hi Kleo

What in particular is it about the 2.3 release that is important here?

Thanks

Aaron Please remember to rate helpful posts to identify useful responses, and mark 'Answered' if appropriate!
New Member

Re: 3750 with Avaya PoE problems

I'm not sure if this is your problem or not but the 3750-24 can support all ports at full power (15.4w). The 3750-48 can support 24 ports at 15.4 Watts, 48 ports at 7.7 Watts, or any combination in-between.

Cisco phones negotiate the power down to 6.9w via CDP so a 3750-48 can have all ports loaded. Because the Avaya phones don't have CDP they can't negotiate properly.

I'm not sure why they renegotiate when you clear the ports.

You may be hitting a power limitation on the 3750 with the Avaya phones.

New Member

Re: 3750 with Avaya PoE problems

One other thing. I believe you can hard set the ports on the 3750 to be PoE class 2 ports. Maybe this would help. I'm not sure what the syntax is.....

Super Bronze

Re: 3750 with Avaya PoE problems

Hi

Thanks - but I did check the 'show power inline' and all the switches in the stack were well within budget power-wise...

Aaron

Aaron Please remember to rate helpful posts to identify useful responses, and mark 'Answered' if appropriate!
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