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Configuring LLDP on MX Series Routers in Enhanced LAN Mode

date_range 30-Nov-23

Starting with Junos OS Release 14.2, devices use Link Layer Discovery Protocol (LLDP) and Link Layer Discovery Protocol–Media Endpoint Discovery (LLDP-MED) to learn and distribute device information on network links.The information enables the device to quickly identify a variety of other devices, resulting in a LAN that interoperates smoothly and efficiently.

This topic describes:

Enabling LLDP on Interfaces

LLDP is enabled on all interfaces by default. If it is disabled, you can enable LLDP by configuring it on all interfaces or on specific interfaces.

To configure LLDP on all interfaces:
```
[edit protocols lldp]
user@router# set interface all 
```

To configure LLDP on a specific interface:

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[edit protocols lldp]
user@router# set interface interface-name 

Note:

On MX Series routers, LLDP cannot be configured on the management Ethernet interface. Issuing the command set protocols lldp interfaceem0 generates the following error message:

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error: name: 'em0': Invalid interface
error: statement creation failed: interface

Adjusting LLDP Advertisement Settings

You can adjust the following settings for LLDP advertisements for troubleshooting or verification purposes. The default values are applied when LLDP is enabled. For normal operations, we recommend that you do not change the default values.

To specify the frequency at which LLDP advertisements are sent (in seconds):
```
[edit protocols lldp]
user@router# set advertisement-interval seconds
```
For example, using the default value:
```
[edit protocols lldp]
user@router# set advertisement-interval 45
```
To specify the number of seconds that LLDP information is held before it is discarded (the multiplier value is used in combination with the advertisement-interval value):
```
[edit protocols lldp]
user@router# set hold-multiplier seconds
```
For example, using the default value:
```
[edit protocols lldp]
user@router# set hold-multiplier 5
```
To specify the number of seconds the device delays before sending advertisements to neighbors after a change is made in a TLV (type, length, or value) element in LLDP or in the state of the local system, such as a change in hostname or management address, set the transmit delay. The transmit delay is enabled by default on switches to reduce the delay in notifying neighbors of a change in the local system. The default value is 2 seconds (if the advertisement-interval value is set to 8 seconds or more) or 1 second (if the advertisement-interval value is set to less than 8 seconds).
```
[edit protocols lldp]
user@router# set transmit-delay seconds
```
For example:
```
[edit protocols lldp]
user@router# set transmit-delay 2
```
Note:
The advertisement-interval value must be greater than or equal to four times the transmit-delay value; otherwise, an error is returned when you attempt to commit the configuration.

Adjusting SNMP Notification Settings of LLDP Changes

You can adjust the following settings for SNMP notifications of LLDP changes. If the values are not specified or if the interval values are set to 0, the notifications are disabled.

To specify the frequency at which LLDP database changes are sent (in seconds):

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[edit protocols lldp]
user@router# set lldp-configuration-notification-interval seconds

For example:

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[edit protocols lldp]
user@router# set lldp-configuration-notification-interval 600

To configure the time interval for SNMP trap notifications to wait for topology changes (in seconds):
```
[edit protocols lldp]
user@router# set ptopo-configuration-trap-interval seconds
```
For example:
```
[edit protocols lldp]
user@router# set ptopo-configuration-trap-interval 600
```
To specify the holding time (used in combination with the ptopo-configuration-trap-interval value) to maintain dynamic topology entries (in seconds):
```
[edit protocols lldp]
user@router# set ptopo-configuration-maximum-hold-time seconds
```
For example:
```
[edit protocols lldp]
user@router# set ptopo-configuration-maximum-hold-time 2147483647
```

Specifying a Management Address for the LLDP Management TLV

You can configure an IPv4 or IPv6 management address to be used in the LLDP Management Address type, length, and value (TLV) messages. Only out-of-band management addresses must be used as the value for the management-address statement.

To configure the management address:

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[edit protocols lldp]
user@router# set management-address ip-address 

Note:

Ensure that the interface with the configured management address has LLDP enabled using the set protocols lldp interface command. If you configure a customized management address for LLDP on an interface that has LLDP disabled, the show lldp local-information command output will not display the correct interface information.

Change History Table

Feature support is determined by the platform and release you are using. Use Feature Explorer to determine if a feature is supported on your platform.

Release

Description

14.2

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