| Summary: | 碩士 === 國立交通大學 === 電信工程系 === 89 === The load of a router on performing the IP address lookup operation is more heavy with the explosive growth of the Internet. In order to prevent it from becoming the bottleneck, a router needs a fast IP address lookup scheme. On the other hand, the router needs an efficient forwarding table structure to store a large amount of routing prefixes. In this thesis, we first adopt the compression bit map (CBM) technique on a general trie to propose an enhanced forwarding table structure, compression trie (CT). Because of its better space-efficiency, the forwarding table can store many routing entries and the table size is still small. Most of the prefixes are of prefix length less than or equal to 24 such that almost all address lookups can be accomplished in one to three memory accesses. On the other hand, we employ a fast forwarding table construction algorithm to rebuild it quickly for solving the route update problem.
Different from the unicast address lookup scheme, a router performs the exact matching search on the destination and source addresses at the same time when executing the multicast address lookup. We adopt the CBM-like technique incorporating with the content addressable memory (CAM) to design a multicast address lookup scheme. Each multicast address lookup needs three memory accesses and the forwarding table size increases under a reasonable scaling factor. Unfortunately, it can not be predicted that how many the groups and sources will the network really have. Therefore the property about the scalability of this forwarding table structure could not be precisely assessed.
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