Configuring Per-Flow Load Balancing Based on Hash Values
By default, Junos OS uses a hashing method based only on the destination address to elect a forwarding next hop when multiple equal-cost paths are available. All Packet Forwarding Engine slots are assigned the same hash value by default.
You can enable router-specific or switch-specific load balancing by configuring the router or switch to assign a unique, load-balance hash value for each Packet Forwarding Engine slot.
This feature is supported only on M120, M320, and MX Series routers.
To configure per-flow load balancing. include the load-balance statement at the [edit forwarding-options] hierarchy level:
To enable per-flow load balancing, you must include the hash-seed statement. Junos OS automatically chooses a value for the hashing algorithm. You cannot configure a specific value for the hash-seed statement when you enable per-flow load balancing.