Digisol DG-FS4526E, Руководство по управлению

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C
HAPTER
15 | Basic Administration Protocols
Link Layer Discovery Protocol
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L
INK
L
AYER
D
ISCOVERY
P
ROTOCOL
Link Layer Discovery Protocol (LLDP) is used to discover basic information
about neighboring devices on the local broadcast domain. LLDP is a Layer 2
protocol that uses periodic broadcasts to advertise information about the
sending device. Advertised information is represented in Type Length Value
(TLV) format according to the IEEE 802.1ab standard, and can include
details such as device identification, capabilities and configuration settings.
LLDP also defines how to store and maintain information gathered about
the neighboring network nodes it discovers.
Link Layer Discovery Protocol - Media Endpoint Discovery (LLDP-MED) is an
extension of LLDP intended for managing endpoint devices such as Voice
over IP phones and network switches. The LLDP-MED TLVs advertise
information such as network policy, power, inventory, and device location
details. LLDP and LLDP-MED information can be used by SNMP applications
to simplify troubleshooting, enhance network management, and maintain
an accurate network topology.
S
ETTING
LLDP T
IMING
A
TTRIBUTES
Use the Administration > LLDP (Configure Global) page to set attributes for
general functions such as globally enabling LLDP on the switch, setting the
message ageout time, and setting the frequency for broadcasting general
advertisements or reports about changes in the LLDP MIB.
CLI R
EFERENCES
"LLDP Commands" on page 999
P
ARAMETERS
These parameters are displayed:
LLDP – Enables LLDP globally on the switch. (Default: Enabled)
Transmission Interval – Configures the periodic transmit interval for
LLDP advertisements. (Range: 5-32768 seconds; Default: 30 seconds)
This attribute must comply with the following rule:
(Transmission Interval * Hold Time Multiplier)


65536, and
Transmission Interval >= (4 * Delay Interval)
Hold Time Multiplier – Configures the time-to-live (TTL) value sent in
LLDP advertisements as shown in the formula below. (Range: 2-10;
Default: 4)
The time-to-live tells the receiving LLDP agent how long to retain all
information pertaining to the sending LLDP agent if it does not transmit
updates in a timely manner.
TTL in seconds is based on the following rule:
(Transmission Interval * Holdtime Multiplier)


65536.
Therefore, the default TTL is 4*30 = 120 seconds.