Maintaining routing information in memory constrained routers

A router in an embodiment associates a corresponding digital code of a set of digital codes to a respective portion of a network address of set of network addresses used in routing information. The routing information is stored in a memory with each digital code substituted for the respective portion of the network address. Memory reduction is obtained as a result. In an embodiment implemented in the context of IPv6 having a prefix and a host identifier for each network address, the portion of a network address corresponds to the prefix. The routing information is stored in the form of a prefix table and topology information. The prefix table stores a mapping of each digital code to a corresponding prefix. The topology information indicates a manner in which each host system and router are connected to each other. Packets are forwarded by examining such routing information.