Dell Networking SONiC: Link Layer Discovery Protocol

Summary: This article explains about Link Layer Discovery Protocol (LLDP) and configuration in Dell Networking SONiC. This article uses a switch running Dell SONiC 4.1.

This article applies to This article does not apply to This article is not tied to any specific product. Not all product versions are identified in this article.

Instructions

 
Prerequisites
We are using standard interface naming to demonstrate the Concepts. See the article 202172 Dell Networking S-Series: Basic Interface Configuration - SONiC 4.0 for more information regarding interface naming


Index

Introduction
Configuration Syntax 
    Enable and Disable LLDP. 
    Configure LLDP Transmit
    Configure LLDP Receive
    Enable LLDP Transmit and Receive.
    Enable LLDP to send the management address and system name and description.
Verify
 

Introduction

Link Layer Discovery Protocol (LLDP), allows the switch to advertise major capabilities and physical descriptions. LLDP is defined in IEEE 802.1AB. This information can be used to help identify system topology and detect bad configurations on the LAN. 

  • LLDP is a one-way protocol; there are no request or response sequences. Stations implementing the transmit function advertise the information, and stations implementing the receive function receive and process the information.
  • The transmit and receive functions can be enabled or disabled separately on each switch port. 
  • LLDP is a vendor-neutral discovery protocol. 
  • The switch receives and periodically transmits LLDP protocol data units (PDUs). The default transmission interval is 30 seconds.
  • LLDP PDU information received from a neighbor expires after a specific amount of time, called time to live (TTL). The default TTL value is 120 seconds.
  • Spanning-tree blocked ports allow LLDP PDUs.

Configuration Syntax

NOTE: LLDP tables are updated in 120 seconds (TTL) after any change in the LLDP configuration.

Enable and Disable LLDP.  

Enable LLDP Globally
admin@DELLSONiC:~$ sonic-cli
DELLSONiC# configure
DELLSONiC(config)# lldp enable
DELLSONiC(config)# end

Disable LLDP Globally 
DELLSONiC# configure  
DELLSONiC(config)# no lldp enable 
DELLSONiC(config)# end

Enable LLDP on a single interface
DELLSONiC# configure 
DELLSONiC(config)# interface Eth slot/port[/subport]
DELLSONiC(config-if-EthX/X)# lldp enable
DELLSONiC(config-if-EthX/X)# end

Disable LLDP on a single interface 
DELLSONiC# configure 
DELLSONiC(config)# interface Eth slot/port[/subport]
DELLSONiC(config-if-EthX/X)# no lldp enable 
DELLSONiC(config-if-EthX/X)# end
 

Configure LLDP Transmit

Performing these commands disable LLDP receive.
Enable LLDP Transmit Globally
admin@DELLSONiC:~$ sonic-cli
DELLSONiC# configure
DELLSONiC(config)# lldp transmit
DELLSONiC(config)# end

Enable LLDP Transmit on a single interface
DELLSONiC# configure 
DELLSONiC(config)# interface Eth slot/port[/subport] 
DELLSONiC(config-if-EthX/X)# lldp transmit
DELLSONiC(config-if-EthX/X)# end


Enable LLDP Transmit and Receive (Click here) 
 

Configure LLDP Receive

Performing these commands disable LLDP transmit.  
Enable LLDP Receive Globally 
admin@DELLSONiC:~$ sonic-cli 
DELLSONiC# configure 
DELLSONiC(config)# lldp receive
DELLSONiC(config)# end 

Enable LLDP Receive on a single interface
DELLSONiC# configure  
DELLSONiC(config)# interface Eth slot/port[/subport]
DELLSONiC(config-if-EthX/X)# lldp receive
DELLSONiC(config-if-EthX/X)# end

Enable LLDP Transmit and Receive (Click here)  
 

Enable LLDP Transmit and Receive.

By default LLDP transmit and receive is enabled by default.
If you have LLDP transmit configured, LLDP receive gets deactivated.
If you have LLDP receive configured, LLDP transmit gets deactivated.
In order to activate both, remove LLDP receive and LLDP transmit.
Enable LLDP Transmit and Receive Globally 
admin@DELLSONiC:~$ sonic-cli 
DELLSONiC# configure 
DELLSONiC(config)# no lldp receive
DELLSONiC(config)# no lldp transmit
DELLSONiC(config)# end 

Enable LLDP Transmit and Receive on a single interface
DELLSONiC# configure  
DELLSONiC(config)# interface Eth slot/port[/subport]
DELLSONiC(config-if-EthX/X)# no lldp receive
DELLSONiC(config-if-EthX/X)# no lldp transmit
DELLSONiC(config-if-EthX/X)# end
 

Enable LLDP to send the management address and system name and description.

By default, LLDP advertises system-name and system-description.
To advertise management-address by LLDP, we must configure lldp tlv-select management-address manually.  
Use bellow configuration to enable system-name, system-description and management-address
DELLSONiC# configure
DELLSONiC(config)# lldp system-name <STRING>
DELLSONiC(config)# lldp system-description <STRING>
DELLSONiC(config)# lldp tlv-select management-address
DELLSONiC(config)#end

Disable system-name, system-description and management-address
DELLSONiC# configure
DELLSONiC(config)# no lldp system-name
DELLSONiC(config)# no lldp system-description
DELLSONiC(config)# no lldp tlv-select management-address
DELLSONiC(config)#end

You have an option to manually specify the IPv4/IPv6 address of management address manually
DELLSONiC# configure
DELLSONiC(config)# interface Eth slot/port[/subport]
DELLSONiC(config-if-Eth1/1)# lldp tlv-set management-address <ipv4/ipv6> <address>
DELLSONiC(config-if-Eth1/1)# end

*Applying this command will make Switch to send LLDP in the specific interface with configured IPV4/IPV6 address, rather than management port IP address.

To disable use
DELLSONiC# configure
DELLSONiC(config)# interface Eth slot/port[/subport]
DELLSONiC(config-if-Eth1/1)# lldp tlv-set management-address <ipv4/ipv6>
DELLSONiC(config-if-Eth1/1)# end


 

Verify

Configuration Syntax
DELLSONiC# show lldp table Show summery of all LLDP Neighbors.
DELLSONiC# show lldp neighbor Show details of all LLDP Neighbors.
DELLSONiC# show lldp neighbor Eth slot/port[/subport] Show details of LLDP Neighbors in a specific interface.
DELLSONiC# show lldp statistics Show LLDP statistics of all LLDP Neighbors.
DELLSONiC# show lldp statistics Eth slot/port[/subport] Show LLDP statistics in a specific interface.

Sample Output
DELLSONiC# show lldp table
------------------------------------------------------------------------------------------------------
LocalPort           RemoteDevice        RemotePortID        Capability          RemotePortDescr
-------------------------------------------------------------------------------------------------------
Eth1/1              DELL-EDGE-sonic               Eth1/1              R                   Ethernet0
DELLSONiC# show lldp neighbor Eth 1/1
-----------------------------------------------------------
LLDP Neighbors
-----------------------------------------------------------
Interface:   Eth1/1,via: LLDP
  Chassis:
    ChassisID:    XXXXXXXXXXXXXXXXXXXXXXXX
    SysName:      DELL-EDGE-sonic
    SysDescr:     DELL-CORE
    TTL:          120
    MgmtIP:       30.0.0.1
    Capability:   ROUTER, ON
  Port
    PortID:       Eth1/1
    PortDescr:    Ethernet0
  LLDP-MED
    Device Type:  Network Connectivity Device
    Capability:   Capabilities, yes
    Capability:   Ext_mdi_power_pd, yes
    Capability:   Inventory, yes
    Capability:   Network_policy, yes
    Inventory
      Hardware Rev:  XXXXXXXXXXXXXXXXXXXXXXXX
      Software Rev:  XXXXXXXXXXXXXXXXXXXXXXXX
      Firmware Rev:  XXXXXXXXXXXXXXXXXXXXXXXX
      Serial Number:
DELLSONiC# show lldp statistics Eth 1/1
LLDP Statistics
---------------------------------
Interface: Eth1/1
    Transmitted      : 60
    Received         : 45
    Discarded        : 0
    Unrecognized TLV : 0
    Ageout           : 1
---------------------------------

Affected Products

Enterprise SONiC Distribution, PowerSwitch E3200-ON Series, Dell EMC Networking N3200-ON, PowerSwitch S5212F-ON, PowerSwitch S5224F-ON, PowerSwitch S5232F-ON, PowerSwitch S5248F-ON, PowerSwitch S5296F-ON, PowerSwitch Z9100-ON, PowerSwitch Z9264F-ON , PowerSwitch Z9332F-ON, PowerSwitch Z9432F-ON ...
Article Properties
Article Number: 000218154
Article Type: How To
Last Modified: 16 Oct 2023
Version:  4
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