multipath (Add-Path)

Syntax

Hierarchy Level

Release Information

Statement introduced in Junos OS Release 16.1R2.

Description

You can restrict BGP add-path to advertise contributor multiple paths only. Advertising all available multiple paths might result in a large overhead of processing on device memory. Selective advertising of multiple paths facilitates Internet service providers and data centers that use route reflector to build in-path diversity in IBGP. You can limit and configure up to six prefixes that the BGP multipath algorithm selects.

For example, if a routing device has four paths to a destination in its routing table and is configured to advertise up to two paths, only contributor paths for load balancing are chosen. The best contributor path is the active path and BGP advertises this path by default. The second best contributor path is selected and this process is repeated until the specified number of paths is reached, in this case two additional paths to the same destination are selected for load balancing.

Required Privilege Level

routing—To view this statement in the configuration.

routing-control—To add this statement to the configuration.