Unified Load Balancer Configuration and Administration Guide, Release 2026.02

PDF

Neighbor discovery

Updated: April 23, 2026

Want to summarize with AI?

Log in

Overview

Details neighbor discovery for technical implementation and operations. It covers how the neighbor discovery works, configuring the refresh interval, interfaces, and node labels, and monitoring neighbor entries.

Neighbor discovery ensures stable network connectivity by addressing issues with ARP entries for neighbor IPs being removed intermittently. This feature is supported to prevent traffic drops by maintaining these entries.

How the neighbor discovery works

Neighbor discovery enables administrators to configure neighbor IPs and interfaces using the CLI. The process can be tailored to specific nodes by using labels.

  • Administrators can configure multiple interfaces, each with their own IP addresses.

  • Discovery is limited to nodes matching specified labels, or all nodes if no label is set.

Summary

Neighbor discovery involves the following key actors and components:

  • Administrator: Configures neighbor IPs and interfaces using the CLI.

  • CLI: Provides commands to set up neighbor discovery parameters.

  • Nodes: Participate in neighbor discovery based on configured labels.

Administrators use the CLI to configure neighbor discovery, which is then dynamically applied to nodes matching the specified labels. If no label is configured, all nodes are included in the discovery process.

Workflow

These stages describe how neighbor discovery is configured and applied across nodes.

  1. The administrator uses the CLI to configure neighbor IPs and interfaces, specifying labels if needed.
    • Access the CLI and enter neighbor discovery configuration mode.
    • Specify interfaces and assign IP addresses for each neighbor.
    • Optionally, configure labels to restrict discovery to specific nodes.
    Neighbor discovery is limited to nodes matching the specified labels. If no label is configured, discovery is performed on all nodes. Configuration changes are dynamically applied across nodes, updating neighbor entries as needed.

Configure the refresh interval, interfaces, and node labels

The following steps describe how to configure the refresh intervals and multiple interfaces with associated IPs.

Procedure

1.

Enter the global configuration mode.

Example:

[cluster1/data] lbs# config
2.

Configure the neighbor discovery details.

Example:

lbs(config)# neighbor-discovery
3.

Configure the refresh interval of neighbors in seconds.

The refresh interval is an integer from 1 to 3600 seconds. Default value is 30 seconds.

Example:

lbs(config)# neighbor-discovery refresh-interval 45
4.

Configure the interface through which the BGP neighbors should be reachable. Then, specify the associated IPv4 and IPv6 next-hop addresses.

Note
You can set up multiple interfaces, each with several IP addresses.

Example:

lbs(config)# neighbor-discovery interface v500
            lbs(config*)# neighbor-discovery interface v500 nexthop 7.7.7.3
            lbs(config*)# neighbor-discovery interface v500 nexthop 7:7:7::3
5.

Specify the node selector using key-value pairs.

Example:

lbs(config)# neighbor-discovery node-selector key feature value bgp

Neighbor discovery will be performed on each node matching any of the configured node labels. If no label is configured, neighbor discovery is performed on all nodes.
6.

Save and commit the configuration.

Example:

lbs(config)# end

Use the following sample configuration to configure neighbor discovery service.

config
        neighbor-discovery
        refresh-interval 45
        interface v500
        nexthop 7.7.7.3
        nexthop 7:7:7::3
        exit
        interface v501
        nexthop 6.6.6.3
        nexthop 6:6:6::3
        exit
        interface v502
        nexthop 5.5.5.3
        nexthop 5:5:5::3
        exit
        node-selector
        key frontend value protocol
        key test1 value value1
        exit
        exit

Monitor neighbor entries

Verify the entries using the following show command:

lbs# show running-config neighbor-discovery
neighbor-discovery
refresh-interval 10
node-selector
key key1 value value1
key key2 value value2
exit
interface v500
nexthop 7.7.7.3
nexthop 7:7:7::3
exit
interface v501
nexthop 6.6.6.3
nexthop 6:6:6::3
exit
exit