Dynamic Host Control Protocol (DHCP) enables you to automatically assign reusable IP addresses to DHCP clients. The Cisco IOS DHCP Server feature is a full DHCP server implementation that assigns and manages IP addresses from specified address pools within the router to DHCP clients. If the Cisco IOS DHCP Server cannot satisfy a DHCP request from its own database, it can forward the request to one or more secondary DHCP servers defined by the network administrator.

Interface Commands (show ip interface -- tx-queue-limit)

Cisco IOS Configuration Fundamentals Command Reference
April 2010

pin-outs of Cisco cables including rollover cables

eigrp commands

ip networking training

subnet training document

dec binary hex chart

class B network cheat sheet

Wikipedia article on the OSI network model

nice online calc for networking

The paper about tcp networking

A chart of net-mask and host address if sub netting the last octet

backbone maps