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Cisco and LLDP (Link Layer Discovery Protocol)

Cisco is working with the IEEE to develop a standards-based version of CDP called LLDP.

I can find no mention of a time line for Cisco to include LLDP support in their switches.

LLDP will be an EXTREMELY useful protocol to have in our environment where we are required to integrate Avaya IP Phones into our network which is all Cisco. We can't use CDP, obviously, and without LLDP we won't have the ability to dynamically install a phone into the switch - which will be a huge pain for us.

Does anyone know when they will offer LLDP support in the 3750 switch line?


Re: Cisco and LLDP (Link Layer Discovery Protocol)

technically, you should be able to use avaya ip phones with cisco switches.

the avaya phones do not support CDP but they are able to operate on a VoIP network that is comprised of cisco VoIP gateways, switches, routers, etc.

there are a few cisco specific features that you must disable, per port usually, when connecting an avaya ip phone.

please see the following link for more info:

the 802.1ab ieee standard was ratified in May, 2005, although cisco does not seem to have any devices that currently support it.

excerpt from cco documentation linked below:

"Cisco currently supports a pre-standards-based discovery protocol that provides similar capabilities to the currently released standards-based LLDP-MED. Cisco Discovery Protocol will continue to be fully supported and may be enhanced in the future to address future capabilities that are not currently supported in LLDP-MED. Additionally, Cisco plans to fully support LLDP-MED on its phones and switches."

from link:

New Member

Re: Cisco and LLDP (Link Layer Discovery Protocol)

Thanks for the info qpulos.


Re: Cisco and LLDP (Link Layer Discovery Protocol)

I've also been waiting for cisco to support LLDP for some time now :-( ..and yes having it would make my life a bit simpler from an avaya perspective, but i don't understand your comment about dynamic...setting up vlan "hopping" via option 176 isn't that bad and it's all automatic you do nothing manually on the avaya phones, only setup option 176 scopes in your native/data vlans...i've set up thousands of avaya phones this way. Also, good thing aux/voice vlan works with avaya, but the phone has to do the vlan hop on intial phone setup. After that vlan info retained in phones flash till you move it to another vlan.

I have many of my switch ports configured as follwing for my avaya phones:

Interface FastEthernet0/5

Description to Avaya IP phone and PC

switchport mode access

switchport access vlan 7

switchport voice vlan 100

no ip address

mls qos trust cos

spanning-tree portfast

clarification on vlan hoping with avaya phones was done on this thread:

if you ever get a date for when LLDP will be delivered please share..

New Member

Re: Cisco and LLDP (Link Layer Discovery Protocol)

kleo -

Thanks for the comments. We have our lab environment set up exactly the way you describe and it works great. However, in our production environment, on many of our data subnets, we do not have alot of loose IP addresses to hand out to phones during their initial connection. We can work around this a couple of ways, but ultimately having LLDP - which will push the voice vlan ID down to the phone - will make life that much easier.

I too wish that Cisco would be forthcoming in letting us know a date when LLDP-MED will be available in their switches. Another person replied to my question stating that LLDP had been finialized sometime last year, so Cisco dragging its feet putting LLDP into their switches is aggrevating to say the least.

I know why they are doing that - they want us to us their phones - but eventually the market will be yelling at them enough that they will reluctanlty give us that option. They WILL have to - I just wish it were sooner than later. (now I'll jump off my soap box)


Re: Cisco and LLDP (Link Layer Discovery Protocol)

Agree 1000%