A customer is multihomed to two different routers in your point of presence (POP). Instead of having BGP send all traffic across one of the links, which is the default behavior, you want to load-balance the EBGP traffic from the customer across the two links.
To enable load balancing across multiple EBGP peerings, configure the BGP group to use multipath:
[edit protocols bgp group
set type externalaviva@Router1#
For the load balancing to happen, configure a load-balancing policy:
[edit policy-options] aviva@router1#
set policy-statement[edit routing-options] aviva@Router1#
LoadBalancethen load-balance per-packet
set forwarding-table export
Multihomed connections from a customer's network to the ISP's POP provide redundant Internet connectivity. If one of the links goes down—for example, because a fiber was cut—the second connection provides backup. If the paths from both connections are equal-cost, the default BGP behavior is to select the single best route to a destination. The result is that BGP uses only one of the links to forward traffic. As long as both links are up, the customer wants to use both, spreading the traffic between them to increase the bandwidth ...