Figure 9: LLDP How it works
1. The Ethernet Routing Switch and LLDP-enabled router advertise chassis/port IDs
and system descriptions to each other.
2. The devices store the information about each other in local MIB databases,
accessible by using SNMP.
3. A network management system retrieves the data stored by each device and builds
a network topology map.
LLDP operational modes
LLDP is a one-way protocol.
An LLDP agent can transmit information about the capabilities
and current status of the system associated with its MAC service access point (MSAP)
identifier. The LLDP agent also can receive information about the capabilities and current
status of the system associated with a remote MSAP identifier. However, LLDP agents cannot
solicit information from each other.
You can set the local LLDP agent to transmit only, receive only, or to both transmit and receive
LLDP information. You can configure the state for LLDP reception and transmission using
SNMP or ACLI commands.
Connectivity and management information
The information fields in each LLDP frame are in a Link Layer Discovery Protocol Data Unit
(LLDPDU)
as a sequence of short, variable length information elements known as TLVs (type,
length, value).
Link Layer Discovery Protocol (802.1ab)
64 Configuration — System April 2011
To Next Page
Loading...
