Quarterly Technical Report, October 2000
- Analysis of strong adversary models: We investigated an adversary that
can fail and recover edges in an arbitrary manner, in contrast to
traditional adversary models which leave the network stable for time
long enough for the protocols to accomplish global communication.
- New routing and dissemination protocols: We devised initial routing
protocols that accomplish the task of routing facing the above strong
adversary model. Our protocols operate without using the concept of
a global path, which is standard in the common "weak adversary" models.
Moreover, the operation of these protocols is based solely on locally
available knowledge, eliminating the need to build a global picture of
the network state.
- New replication protocol: We have developed a general replication engine
that allows consistent ordering of actions in a network that is prone to
partitions and crashes.
The main idea has several instances of the engine (several tens) strategically
positioned in the network. The replicas maintain consistent state and recover
from a wide range of possible faults.
The engine software is now going through testing and evaluation.
We have built some of the infrastructure that will allow us to test the
replication engine, inducing faults into practical network settings.
Currently, our tests are still configned to our lab.
- Overlay networks architecture: We started developing the basic building
blocks for our overlay networks architecture. The first step was to develop
Hop - a link level modified selective-repeat protocol that is TCP-fair, uses less CPU, and allows us full control over the forwarding of messages on
the overlay network.
We designed two alternative global flow control schemes. The first scheme is
a cost benefit approach to buffer utilization in the overlay network routers. The second Scheme is a cost benefit approach to capacity utilization of the
overlay links. We are still investigating the tradeoffs between these schemes.
Plans for Next Quarter:
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