The following are resources which explain more about network interfaces.
/usr/share/doc/initscripts-<version>/sysconfig.txt — A guide to available options for network configuration files, including IPv6 options not covered in this chapter.
/usr/share/doc/iproute-<version>/ip-cref.ps — This file contains a wealth of information about the ip command, which can be used to manipulate routing tables, among other things. Use the ggv or kghostview application to view this file.