At the Network Layer, routers handle traffic from one network to another. Although there are many routers on the market, the Cisco brand has really become the most signficant -- defining a standard. Moreover, the Cisco company is responsible for many professional networking certifications, such as Cisco Certified Network Associate (CCNA). In this part of the course, we are becoming more familiar with the command line interface for the Cisco Internetwork Operating System (Cisco IOS). At the same time, much of our activities involving Cisco routers will be quite applicable to routers -- on both the hardware and software levels -- in general.