* the new version makes use of MAC-layer feedback so that bad paths
can be identified quicker and then avoided.
* the new code uses transport layer ACKs that contain feedback from
the collect protocol: when a packet cannot be forwarded due to lack
of resources, the ACK contains a flag that indicates that the packet
could not be forwarded. ACKs also contain the routing metric of the
sender, which improves agility in face of rapid path changes.
* loop detection and management has been improved: with higher path
metric agility, the system is more prone to short-lived routing
loops. Instead of dropping looping packets, the new version adjusts
the routing metric for the routes that exhibit loops so that the
risk for future loops is reduced.
* make use of packet attributes to inform the MAC layer of how many
times packets should be retransmitted.
