Slides from Lecture 4 of 12 September 2002: 04-unix.pdf

You may find this helpful in understanding today's lecture better. Some more resources are given below:

route(4): kernel packet forwarding database.

route(8): manually manipulate the routing tables.

routed(8): RIP router daemon.

Scalable Packet Classification, paper in SIGCOMM'2001 by Florin Baboescu and George Varghese.

Scalable High-Speed Prefix Matching, paper ACM TOCS v19n4, November 2001, in by Waldvogel, Varghese, Turner and Plattner.

And the original Unix routing table paper:
A Tree-Based Packet Routing Table for Berkeley Unix, paper in Winter Usenix 1991, by Keith Sklower.