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Cisco IE 3010 Switch Software Configuration Guide
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Chapter 26 Configuring LLDP, LLDP-MED, and Wired Location Service
Understanding LLDP, LLDP-MED, and Wired Location Service
• 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. Th erefore, LLDP discovers the switch stack,
not the individual stack members.
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 spec ifically 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 an d
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.
By defining a network-policy profile TLV, you can create a profile for voice and voice-signalling by
specifying the values for VLAN, class of service (CoS), differentiated services code point (DSCP),
and tagging mode. These profile attributes are then maintained centrally on the switch and
propagated to the phone.
• 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.
LLDP-MED also supports an extended power TLV to advertise fine-grained power requirements,
end-point power priority, and end-point and network connectivity-device power status. However, it
does not provide for power negotiation between the endpoint and the network connectivity devices.
Starting with Cisco IOS Release 12.2(52)SE, when LLDP is enabled and power is applied to a port,
the power TLV determines the actual power requirement of the endpoint device so that the system
power budget can be adjusted accordingly. The switch processes the requests and either grants or
denies power based on the current power budget. If the request is gra nted, the switch updates the
power budget. If the request is denied, the switch turns off power to the port, generates a syslog
message, and updates the power budget. If LLDP-MED is disabled or if the endpoint does not
support the LLDP-MED power TLV, the initial allocation value (15.4 W) is used throughout the
duration of the connection.