LLDP to determine power with non-cisco phones ?

Unanswered Question
Oct 31st, 2008


We are using Cisco 3750 power over ethernet switch with Nortel 1140E Ip phones.

Is there any way the the 3750 could adjust power consumption automatically via "lldp med-tlv-select power-management" ?

My 1140E is set with LLDP, and if I do a "show LLDP neighbor detail" on the switch, it tells me that it sees the phone and the power needed by the phone (9.6 Watts) but the switchport sticks with the calss 3 PoE value of 15.4 Watts.

Is there any way to make it work like Cisco Phones and CDP ?



I have this problem too.
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Giuseppe Larosa Sat, 11/01/2008 - 06:58

Hello Dominic,

your description looks like the following bug:


A switch configured for Link Layer Discovery Protocol (LLDP) might not correctly report the enabled switch capabilities in the LLDP type, length, and value (TLV) attributes. System capabilities appear correctly, but the enabled capabilities are not identified if the switch is configured only as a Layer 2 switch.

There is no workaround.

Hope to help


dominic.bilodea... Wed, 11/05/2008 - 07:42

Hello Giuseppe

Thanks a lot for the information. Does that mean that I have to enable ip routing on the switch, even if I don't need it ? Anybody found another way to make it work ?


Giuseppe Larosa Wed, 11/05/2008 - 09:44

Hello Dominic,

I have the same impression that the only workaround is to enable routing on the switch.

Probably this activates some IOS routines/functions that are also used in LLDP process.

Hope to help



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