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Cisco ME 3400 Ethernet Access Switch Software Configuration Guide
OL-9639-06
Chapter 24 Configuring LLDP and LLDP-MED
Understanding LLDP and LLDP-MED
LLDP supports a set of attributes that it uses to discover neighbor devices. These attributes contain type,
length, and value descriptions and are referred to as TLVs. LLDP supported devices can use TLVs to receive
and send information to their neighbors. Details such as configuration information, device capabilities,
and device identity can be advertised using this protocol.
LLDP is enabled by default on network node interfaces (NNIs). It is disabled on enhanced network
interfaces (ENIs), but you can enable it. LLDP is not supported on user network interfaces (UNIs).
The switch supports these basic management TLVs. These are mandatory LLDP TLVs.
• Port description TLV
• System name TLV
• System description
• System capabilities TLV
• Management address TLV
These organizationally specific LLDP TLVs are also advertised to support LLDP-MED.
• Port VLAN ID TLV ((IEEE 802.1 organizationally specific TLVs)
• MAC/PHY configuration/status TLV(IEEE 802.3 organizationally specific TLVs)
Understanding LLDP-MED
LLDP for Media Endpoint Devices (LLDP-MED) is an extension to LLDP that operates between
endpoint devices such as IP phones and network devices such as switches. It specifically provides
support for voice over IP (VoIP) applications and provides additional TLVs for capabilities discovery,
network policy, Power over Ethernet, and inventory management.
LLDP-MED supports these TLVs:
• LLDP-MED capabilities TLV
Allows LLDP-MED endpoints to determine the capabilities that the connected device supports and
what capabilities the device has enabled.
• Network policy TLV
Allows both network connectivity devices and endpoints to advertise VLAN configurations and
associated Layer 2 and Layer 3 attributes for the specific application on that port. For example, the
switch can notify a phone of the VLAN number that it should use. The phone can connect into any
switch, obtain its VLAN number, and then start communicating with the call control
• Power management TLV
Enables advanced power management between LLDP-MED endpoint and network connectivity
devices. Allows switches and phones to convey power information, such as how the device is
powered, power priority, and how much power the device needs.
• Inventory management TLV
Allows an endpoint to transmit detailed inventory information about itself to the switch, including
information hardware revision, firmware version, software version, serial number, manufacturer
name, model name, and asset ID TLV.