Method to use to choose next hop when more than one
is available. The round-robin method will send each
packet destined for a given destination to a
different nexthop until all have been used, then
repeat its iteration through the list. src-dest-hash
will use a single nexthop for all traffic originating
at one given IP address and addressed to another
given IP address. dest-hash is similar but uses only
the destination's IP address to compute the nexthop.
round-robin provides greater usage of network
resources, but increases the chance for out of order
packet delivery and similar problems. src-dest-hash
increases the chances that packets will be delivered
in order, but fails to take full advantage of the
capabilities of the network. dest-hash makes the
forwarding algorithm compatible with RSVP when
the latter is enabled on the router.