Below are two possible MSc projects at NLnet Labs (Amsterdam; but
working most of the time in Twente may be possible).
Contact person for these assignment at the UT is Pieter-Tjerk de Boer,
p.t.deboer@utwente.nl .

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      ==================== MSC. PROJECT I ====================

	    Modeling and Analysis of Hierarchical Networks
		      with Byzantine Robustness

Problem Description
-------------------

In a paper by Radia Perlman and Charlie Kaufman [1], a hierarchical
model for networks with Byzantine robustness is presented.  This model
extends previous work on network protocols resilient to Byzantine
failures, that guarantee that nodes A and B can communicate, provided
that at least one honest path connects them.  The hierarchical model
scales to large networks and additionally to guaranteed delivery of
packets with some fair bandwidth, it also has the ability to limit the
number of simultaneous sources it is receiving from and limit receipt
of traffic to the rate at which the destination is capable to
process.


Project Plan
------------

In the hierarchical network model with Byzantine robustness,
management of the switch/router resources is required to provide the
guarantees of packet delivery and traffic rate limit on a per-flow
basis.  This flow resource management is important to achieve both the
above defined guarantees and the scalability of the model to large
networks. 

To assess the scalability behavior, and the packet delivery and rate
limiting guarantees, a simulation model of the hierarchical network
with Byzantine robustness (HNBR) can be developed.  With this
simulation model different strategies can be evaluated, for example
using metrics like efficiency and effectiveness, the scalability of
the approach for different network sizes and topologies (network
hierarchies), etc.

In the project we aim for a conference/journal publication in
collaboration with Radia Perlman.  This of course, given the obtained
project results and analysis.


References
----------

[1] Radia Perlman and Charlie Kaufman, "Hierarchical Networks with
    Byzantine Robustness", COMSNETS 2011.



      ==================== MSC. PROJECT II ====================

	       Load Splitting of Network Traffic Flows
			 (Multipath Routing)

Problem Description
-------------------

Currently, we are in a situation where the network tries to keep
packets in order.  Although out-of-order packet receipt shouldn't be a
problem for IP layer 3 protocols, e.g., TCP could handle this, bad
performance or actually failure (?) can be a result.  Still for
performance, we want to spread traffic among lots of paths.  There are
various strategies for keeping packets in order over parallel paths.
One of the more successful approaches identifies (TCP) flows and
switches forward packets within a flow to the same port interface.


Project Plan
------------

Flow-based forwarding in switches/routers is based on (destination,
source, protocol type, TCP ports) tuples in the forwarding table.
There is a claim that for better spreading of traffic load, a central
entity knows what all the flows are, such that it can carefully place
them.  However, given the highly dynamic behavior of traffic volumes,
it seems that switches are in a better position to load-split traffic
than a central fabric manager.  The switch can split path based on
local queues and congestion, and can rehash the flows to spread the
load. 

To evaluate, compare, and understand the traffic utilization for
different load split strategies, a simulation model and implementation
has to be realized.  With the simulation, the alternatives of the
perfect knowledge central entity, and the various (more) distributed
flow load splitting strategies can be evaluated and analyzed.
Interesting question is whether local queue information is sufficient,
or do we need 1 hop or n hop congestion information?  There are costs
incurred to find out congestion information n hops away.