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Catalyst 3750 SwitchSoftware Configuration Guide
OL-8550-09
Chapter27 Configuring LLDP, L LDP-MED, and Wired Location Service
Understanding LLDP, LLDP-MED, and Wired Location Service
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 granted, 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.
You can change power settings by entering the power inline {auto [max max-wattage] | never |
static [max max-wattage]} interface configuration command. By default the PoE interface is in
auto mode; If no value is specified, the maximum is allowed (15.4 W).
•Inventory management TLV
Allows an endpoint to send 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.
•Location TLV
Provides location information from the switch to the endpoint device. The location TLV can send
this information:
–
Civic location information
Provides the civic address information and postal information. Examples of civic location
information are street address, road name, and postal community name information.
–
ELIN location information
Provides the location information of a caller. The location is determined by the Emergency
location identifier number (ELIN), which is a phone number that routes an emergency call to
the local public safety answering point (PSAP) and which the PSAP can use to call back the
emergency caller.
Wired Location Service
The switch uses the wired location service feature to send location and attachment tracking information
for its connected devices to a Cisco Mobility Services Engine (MSE). The tracked device can be a
wireless endpoint, a wired endpoint, or a wired switch or controller. The switch notifies the MSE of
device link up and link down events through the Network Mobility Services Protocol (NMSP) location
and attachment notifications.
The MSE starts the NMSP connection to the switch, which opens a server port. When the MSE connects
to the switch there are a set of message exchanges to establish version compatibility and service
exchange information followed by location information synchronization. After connection, the switch
periodically sends location and attachment notifications to the MSE. Any link up or link down events
detected during an interval are aggregated and sent at the end of the interval.
When the switch determines the presence or absence of a device on a link-up or link-down event, it
obtains the client-specific information such as the MAC address, IP address, and username. If the client
is LLDP-MED- or CDP-capable, the switch obtains the serial number and UDI through the LLDP-MED
location TLV or CDP.