Configuring LLDP – Link Layer Discovery Protocol

You configure LLDP like this in [edit protocols] hierarchy level.:

[edit]
protocols {
lldp {
advertisement-interval 30;
hold-multiplier 4;
interface all {
disable;
}
interface ge-1/1/1;
lldp-configuration-notification-interval 30;
ptopo-configuration-maximum-hold-time 300;
ptopo-configuration-trap-interval 30;
transmit-delay 2;
}
}

The following statements have default values:

• advertisement-interval  -The default value is 30 seconds. The allowable range is from 5 through 32768 seconds.
• hold-multiplier  -The default values is 4. The allowable range is from 2 through 10.
• ptopo-configuration-maximum-hold-time  -The default value is 300 seconds. The allowable range is from 1 through 2147483647 seconds.
• transmit-delay  -The default values is 2 seconds. The allowable range is from 1 through 8192 seconds.

The following statements must be explicitly configured:

• lldp-configuration-notification-interval -The allowable range is from 0 through 3600 seconds. There is no default value.
• ptopo-configuration-trap-interval -The allowable range is from 1 through 2147483647 seconds. There is no default value.

To disable LLDP on all or a particular interface, include the interfaces statement at the [edit protocols lldp] hierarchy level:

interface (all | interface-name) {
 disable;
 }

To disable LLDP on all interfaces, use the all option. To disable LLDP on a particular interface, include the disable statement with the interface name.

To configure LLDP on a T Series router within a TX Matrix, you must specify the interface name in the LLDP configuration for the TX Matrix. The important The interface-name must be the physical interface (for example, ge-1/0/0) and not a logical interface (unit).

The advertisement interval determines the frequency that an LLDP interface sends LLDP advertisement frames. The default value is 30 seconds. The hold multiplier determines the multiplier to apply to the advertisement interval. The resulting value in seconds is used to cache learned LLDP information before discard. The default value is 4. When used with the default advertisement interval value of 30 seconds, this makes the default cache lifetime 120 seconds. Remember that in Cisco CDP protocol we also have these timers but in slightly different way of configuring. There are CDP timer (time between two advertisements) and CDP Holdtime as the time that the entry will stay in the CDP table without new announcement. The difference is in the default duration to, CDP timer is 60 seconds and Juniper LLDP is 30. LLDP holt timer is defined in multiplier value. How many times more that LLDP timer, the default is 4 that means 30*4= 120 seconds. The Cisco CDP default holdtime is 180 seconds.

The transmit delay determines the delay between any two consecutive LLDP advertisement frames. The default value is 2 seconds. The allowable range is from 1 through 8192 seconds. You adjust this parameter by including the transmit-delay statement at the [edit protocols lldp] hierarchy level.

The physical topology configuration maximum hold time determines the time interval for which an agent device maintains physical topology database entries. The default value is 300 seconds. The allowable range is from 1 through 2147483647 seconds. You adjust this parameter by including the ptopo-configuration-maximum-hold-time statement at the [edit protocols lldp] hierarchy level.

The LLDP configuration notification interval determines the period for which trap notifications are sent to the SNMP Master Agent when changes occur in the database of LLDP information. This capability is disabled by default. The allowable range is from 0 (disabled) through 3600 seconds. You adjust this parameter by including the lldp-configuration-notification-interval statement at the [edit protocols lldp] hierarchy level.

The physical topology configuration trap interval determines the period for which trap notifications are sent to the SNMP Master Agent when changes occur in the global physical topology statistics. This capability is disabled by default. You adjust this parameter by including the ptopo-configuration-trap-interval statement at the [edit protocols lldp] hierarchy level.

You should type these commands to see LLDP functionality:

show lldp
show lldp neighbors interface-name
show lldp statistics interface-name
show lldp local-information
show lldp remote-global-statisitics

You can clear LLDP neighbor information or statistics globally or on an interface:

clear lldp neighbors interface-name
clear lldp statistics interface-name

You can display basic information about LLDP with the show lldp detail command:

user@host> show lldp detail
LLDP                   : Enabled
Advertisement interval : 30 Second(s)
Transmit delay         : 2 Second(s)
Hold timer             : 4 Second(s)
Notification interval  : 30 Second(s)
Config Trap Interval   : 300 Second(s)
Connection Hold timer  : 60 Second(s)

Interface      LLDP       Neighbor count
ge-1/1/1       Enabled    0         

LLDP basic TLVs supported:
Chassis identifier, Port identifier, Port description, System name, System description,
System capabilities, Management address.

LLDP 802 TLVs supported:
Link aggregation, Maximum frame size, MAC/PHY Configuration/Status, Port VLAN ID, Port VLAN name.