System IP load balancing

This enhancement adds an option to add the system IP address into the hash algorithm. This adds a per system variable so that traffic being forward through multiple routers with similar ECMP paths have a lower chance of always using the same path to a destination.

Currently, if multiple routers have the same set of ECMP next hops, traffic uses the same next hop at every router hop. This can contribute to the unbalanced utilization of links. The new hash option avoids this issue.

This feature when enabled, enhances the default per-flow hashing algorithm described earlier. It however does not apply to services which packets are hashed based on service-id or when per-service consistent hashing is enabled. This hash algorithm is only supported on IOM3-XPs/IMMs or later generations of hardware. The System IP load balancing can be enabled per-system only.