User's Manual

C HAPTER 4 | Configuring the Switch
Link Layer Discovery Protocol
– 160 –
(Transmission Interval * Transmission Hold Time) ≤ 65536.
Therefore, the default TTL is 30*3 = 90 seconds.
◆ Tx Delay – Configures a delay between the successive transmission of
advertisements initiated by a change in local LLDP MIB variables.
(Range: 1-8192 seconds; Default: 2 seconds)
The transmit delay is used to prevent a series of successive LLDP
transmissions during a short period of rapid changes in local LLDP MIB
objects, and to increase the probability that multiple, rather than single
changes, are reported in each transmission.
This attribute must comply with the rule:
(4 * Transmission Delay) ≤ Transmission Interval
◆ Tx Reinit – Configures the delay before attempting to re-initialize after
LLDP ports are disabled or the link goes down. (Range: 1-10 seconds;
Default: 2 seconds)
When LLDP is re-initialized on a port, all information in the remote
system’s LLDP MIB associated with this port is deleted.
LLDP Interface Attributes
◆ Port – Port identifier.
◆ Mode – Enables LLDP message transmit and receive modes for LLDP
Protocol Data Units. (Options: Disabled, Enabled - TxRx, Rx only,
Tx only; Default: Disabled)
◆ CDP Aware – Enables decoding of Cisco Discovery Protocol frames.
(Default: Disabled)
If enabled, CDP TLVs that can be mapped into a corresponding field in
the LLDP neighbors table are decoded, all others are discarded. CDP
TLVs are mapped into LLDP neighbors table as shown below:
■
CDP TLV “Device ID” is mapped into the LLDP “Chassis ID” field.
■
CDP TLV “Address” is mapped into the LLDP “Management Address”
field. The CDP address TLV can contain multiple addresses, but only
the first address is shown in the LLDP neighbors table.
■
CDP TLV “Port ID” is mapped into the LLDP “Port ID” field.
■
CDP TLV “Version and Platform” is mapped into the LLDP “System
Description” field.
■
Both the CDP and LLDP support “system capabilities,” but the CDP
capabilities cover capabilities that are not part of LLDP. These
capabilities are shown as “others” in the LLDP neighbors table.
If all ports have CDP awareness disabled, the switch forwards CDP
frames received from neighbor devices. If at least one port has CDP
awareness enabled, all CDP frames are terminated by the switch.
When CDP awareness for a port is disabled, the CDP information is not
removed immediately, but will be removed when the hold time is
exceeded.