615 paper 10 This paper presents associativity based routing, in which the protocol
selects routes based on nodes being have states of "associativity" based
on periods of non-movement.  The goal is to establish
routes that are stable (ie long-lived), and attain higher throughput. It
is a reactive protocol, dealing with route requests on a per need
basis.  The paper claims that the protocol's associate property also
allows fault tolerance in times of base station failures.  Also, they
claim the protocol is free from loops, deadlock, and packet duplicates.


ABR uses a combination of point to point and broadcast routing approaches
- routes are initiated by the source and set-up based on demand. ABR
makes routing decisions at the destination, so that only the best route
will be selective and made active to avoid packet duplicates.    

The "rule of associativity" that the paper discusses states that a mobile
hosts' association with its neighbor changes as it is migrating and its
movement period can be identified by association ticks which are
transmitted on the data link protocol, where each host sends hello
messages and updates its associativity ticks depending on the nodes it is
surrounded by.

By appending associativity tick numbers to route requests by intermediate
nodes, the destination can select a route according to its knowledge of
all the possible routes.  Breaks in links and intermediate node movements
are handled by passing new requests up to the source if the source of the
break is in the lower half of the route and the destination if the break
is in the upper half.


Finally, the paper provided simulations which were not as detailed as
some of the other papers we have read (well, at least they had simulations
in this paper), and more information would have been nice, such as
protocol overhead and such.  The results seemed a little hard to read.

comments:

This protocol was interesting because it had data flow acknowledgment and
re-transmission scheme incorporated in the protocol.  This has its pros
and cons, depending on what you're using it for and what protocols are on
top of it.

This protocol also seemed to be most effective for a very specific type
of ad hoc network where nodes move for a short period of time but expeience 
a "dormant" period where they stay in the same area.  The interesting
thing is that this gives priority to nodes that are more stationary.  


