Tlv Types - H3C S5500-EI Series Operation Manual

Operation Manual – LLDP
H3C S5500-EI Series Ethernet Switches
the two cases, an interval exists between two successive operations of sending
LLDPDUs. This prevents the network from being overwhelmed by LLDPDUs even if the
LLDP operating mode changes frequently.
To enable the neighboring devices to be informed of the existence of a device or an
LLDP operating mode change (from the disable mode to TxRx mode, or from the Rx
mode to Tx mode) timely, a device can invoke the fast sending mechanism. In this case,
the interval to send LLDPDUs changes to one second. After the device sends specific
number of LLDPDUs, the interval restores to the normal. (A neighbor is discovered
when a device receives an LLDPDU and no information about the sender is locally
available.)
III. Receiving LLDPDUs
An LLDP-enabled device operating in the TxRx mode or Rx mode checks the TLVs
carried in the LLDPDUs it receives and saves the valid neighboring information. An
LLDPDU also carries a TTL (time to live) setting with it. The information about a
neighboring device maintained locally ages out when the corresponding TTL expires.
The TTL of the information about a neighboring device is determined by the following
expression:
You can set the TTL by configuring the TTL multiplier. Note that the TTL can be up to
65535 seconds. TTLs longer than it will be rounded off to 65535 seconds.

1.1.3 TLV Types

TLVs encapsulated in LLDPDUs fall into these categories: basic TLV, organization
defined TLV, and MED (media endpoint discovery) related TLV. Basic TLVs are the
base of device management. Organization specific TLVs and MED related TLVs are
used for enhanced device management. They are defined in standards or by
organizations and are optional to LLDPDUs.
I. Basic LLDP TLVs
Table 1-1
TTL multiplier × LLDPDU sending interval.
lists the basic LLDP TLV types that are currently in use.
1-2
Chapter 1 LLDP Configuration