Operators can enable Layer 4 load balancing to include TCP/UDP source/destination port numbers in addition to source/destination IP addresses in per-flow hashing of IP packets. By including the Layer 4 information, a SA/DA default hash flow can be sub-divided into multiple finer-granularity flows if the ports used between a specific SA/DA vary.
Layer 4 load balancing can be enabled/disabled on system and interface levels. When enabled, the extra Layer 4 port inputs apply to per-flow hashing for unicast IP traffic and multicast traffic (if mc-enh-load-balancing is enabled).