Configuring Per-Flow Load-Balancing Information

By default, when there are multiple equal-cost paths to the same destination, the JUNOS software chooses one of the next-hop addresses at random.

On routing platforms with the Internet Processor II application-specific integrated circuit (ASIC), you have three additional options:

You can specify what information the routing platform uses for per-flow load balancing based on port data (instead of on source and destination IP addresses only). For aggregated Ethernet and aggregated SONET/SDH interfaces, you can load-balance based on the Multiprotocol Label Switching (MPLS) label information. For more information, see Configuring the Load-Balance Per-Packet Action.
You can also configure per-prefix load balancing, which allows you to configure a hash value that enables the router to elect a next hop independently of the route chosen by other routers. For more information, see Configuring Per-Prefix Load Balancing.
You can also configure per-flow load balancing, which allows you to configure a unique, load balance hash value for each Packet Forwarding Engine slot. For more information, see Configuring Per-Flow Load Balancing Based on Hash Values.