JUNOS Enterprise Switching

LLDP with Media Endpoint Discovery

With so many IP telephony pieces and vendors available, it’s often difficult to ensure that each device is configured and operating properly. This is usually done with some type of manual configuration and discovery.

LLDP comes to the rescue with Media Endpoint Discovery, which is an LLDP extension defined in TIA-1057. TIA-1057 was specifically written in order to support interoperability and discovery between VoIP devices. These devices can include IP phones, gateways, IP media servers, and so on.

LLDP-MED provides the following benefits:

Network policy discovery

Allows endpoints to advertise VLAN IDs and DSCP settings

PoE management

Allows endpoints to advertise their PoE requirements

Inventory management discovery

Stores all the relevant information (software, serial number, etc.) for inventory and reporting purposes

Location discovery

Identifies the location of the IP phone on the switch port for E-911 services

Not all vendors support LLDP-MED. Examples of IP phones that support LLDP-MED functionality include:

• Avaya 9600 series with firmware 1.2.1

• Avaya 9600 series with firmware 2.6

• Cisco phones (7609G, 7911G, 7931G, 7941G, 7945G, 7961G, 7965G, 7970G, 7971G, and 7975G)

• Nortel phones (1110, 1150, 1210, 1220, and 1230)

LLDP-MED is essentially additional TLVs that are advertised in a standard LLDP message. So, all the LLDP features discussed previously are maintained. Essentially, new TLVs are defined; here are some common LLDP-MED TLVs:

LLDP-MED capabilities ...