Cisco CATALYST 2960

26-2
Catalyst 2960 and 2960-S Switches Software Configuration Guide, Release 15.0(1)SE
OL-26520-01
Chapter 26 Configuring LLDP, LLDP-MED, and Wired Location Service
Understanding LLDP, LLDP-MED, and Wired Location Service
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. This protocol can advertise details such as configuration
information, device capabilities, and device identity.
The switch supports these basic management TLVs. These are mandatory LLDP TLVs.
• Port description TLV
• System name TLV
• System description TLV
• 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)
Note A switch stack appears as a single switch in the network. Therefore, LLDP discovers the switch stack,
not the individual stack members.
When you configure LLDP or CDP location information on a per-port basis, remote devices can send
Cisco Medianet location information to the switch. For information, go to
http://www.cisco.com/en/US/docs/ios/netmgmt/configuration/guide/nm_cdp_discover.html.
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, inventory management and location information. By default, all
LLDP-MED TLVs are enabled.
LLDP-MED supports these TLVs:
• LLDP-MED capabilities TLV
Allows LLDP-MED endpoints to determine the capabilities that the connected device supports and
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 to any
switch, obtain its VLAN number, and then start communicating with the call control.