A Bloom lter is data structure for representing sets in a compressed form, which has
many applications. Bloom lters save time and space, but produce errors known as
false positives.
Recently it has been suggested that Bloom lters can be used for encoding paths
in graphs, for the purpose of delivering messages in computer networks. False positives
mean that a message will be delivered not only to its destination, but also to
some nodes to which it should not have been delivered. Some ways of reducing the
probability of such errors have been discussed in the literature.
In this thesis, a new approach is suggested. Instead of choosing labels for edges
at random (as is done in the standard Bloom lter approach), labels for edges are
chosen based on the graph and the position of an edge in the graph. It is shown that
under some assumptions (the graph is known, and only shortest paths are encoded),
there will be no false positives leading to a message being delivered to a wrong node. Chapter 1 introduces the routing scenario, the Standard Bloom Filters and the
encoding methods that are investigated in the following chapters. Dierent types of
assumptions concerning the graphs are applied in further chapters. Shortest paths in
rectangular grids are encoded in Chapter 2; then king's graphs, hexagonal grids and
triangular grids are studied in Chapters 3; 4 and 5, respectively. Another realistic
networks is considered in Chapter 6. Finally, a way to generalise these encoding
methods to arbitrary graphs is discussed in Chapter 7, which concludes the thesis. |