In TCP/IP how does multipath per connection routing work?

In general, multipath routing provides the routing distribution necessary to balance the network utilization of outbound packets by load splitting. Multipath routing requires multiple equal-cost routes that are either defined statically or added dynamically by routing protocols (except for RIP, which does not provide multipath routing).

If there are multiple equal-cost routes to a destination and MULTIPATH PERCONNECTION is specified, TCP/IP, upon first sending an IP packet to a given destination, selects a route on a round-robin basis from a multipath routing list to that destination host. The selected route is used to route IP packets for a given connection or connectionless oriented association to that destination host. Connection or connectionless oriented IP packets using the same association always use the same route, as long as that route is active.

When specified on the IPCONFIG statement, the MULTIPATH PERCONNECTION parameter is confirmed by the message:

EZZ0632I MULTIPATH PERCONNECTION SUPPORT IS ENABLED

When specified on the IPCONFIG6 statement, the MULTIPATH PERCONNECTION parameter is confirmed by the message:

EZZ0704I IPV6 MULTIPATH PERCONNECTION SUPPORT IS ENABLED

If MULTIPATH is specified without any subparameters, the default is PERCONNECTION. The MULTIPATH parameter has no effect if there are no multipath routes in the TCP/IP configuration.