Basic Functionalities of Routers, Evolution of Router Architecture, Key Components of a Router, Network Processor, IP-Address Lookup and Routing Table, Construction of Optimal Routing Tables, Matching Techniques, Difficulty of the Longest-Prefix Matching Problem, , Multibit Tries. Pipelined Multibit Tries. Efficient Data Structures for Bursty Access Patterns. Caching Technologies: Suez Lookup Algorithm, Host Address Range Cache, Prefix Caching Schemes, Multi-Zone Caches, Hashing Schemes: Binary Search on Hash Tables, Parallel Hashing in Prefix Length, Multiple Hashing Schemes, Using Bloom Filter. TCAM-Based Routing-Table Partitioning, Technologies Forwarding Engine.