General Networking TheoryThis chapter ensures you are prepared for questions in the Cisco Certified Internetwork Expert (CCIE) written exam that deal with general networking theories. General networking theories include Open System Interconnection (OSI) models, routing concepts, networking standards, and protocol mechanics. As you might expect, many of the concepts reviewed in this chapter receive additional and more specific coverage elsewhere in this text. It is critical that you review the topics at this level as well, however. The information contained here is not repeated later at all. The CCIERouting/Switching candidate should have several years of hands-on experience with Cisco gear. Therefore, this section also ensures you are well-versed in Cisco device operations. This section focuses on general show and debug commands and their usage, as well as physical structures within almost all Cisco equipment. It also reviews basic device operational characteristics including device access, password recovery, Simple Network Management Protocol (SNMP), and Switched Port Analyzer (SPAN).