Specifications

8-2
System Management Software Configuration Guide for Cisco IE 2000U and Connected Grid Switches
Chapter 8 Configuring LLDP and LLDP-MED
Information About LLDP and LLDP-MED
To support non-Cisco devices and to allow for interoperability between other devices, the switch
supports the IEEE 802.1AB Link Layer Discovery Protocol (LLDP). LLDP is a neighbor discovery
protocol that is used for network devices to advertise information about themselves to other devices on
the network. This protocol runs over the data-link layer, which allows two systems running different
network layer protocols to learn about each other.
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)
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