"If the class is to lead yourself to the CCIE on the right track, seriously reading the reference book is to catch the fast train to learn CCIE, this process is very difficult. Formal learning can form a holistic conceptual system in your mind, which is equivalent to setting up a skeleton, but the detailed content depends on your own reading.
The main bibliography:
1. TCP / IP Routing Technology (Vol. 1) ROUTING TCP / IP VOLUME 1 (Author: JEFF DOLE)
Static routing, RIP, RIPv2, IGRP, EIGRP, OSPF, ISIS, etc.
2. TCP / IP Routing Technology (Volume 2) ROUTING TCP / IP VOLUME 2 (Author: JEFF DOLE)
BGP, MULTICAST, NAT, SNMP, NTP, IP ACCOUNTING
3. Catalyst 3550 Multilayer Switch Software Configuration Guide, 12.1(19)EA1"