Today's ultra-connected society requires that Internet access be provided almost anywhere. Because of this, networks play a central role in today's business and compute environment. In short, the network touches everything. Without the network, we would not have the Internet, cloud computing, video streaming to our homes, or social media. In general, there are three types of networks:
Local-area networks (LAN) are an inexpensive way to connect and share resources. In today's environment, LANs are found almost everywhere: homes, small business, enterprises, schools, hospitals, and universities.
Wide-area networks (WAN) connect LANs together over many distances and media types.
Storage-area networks (SAN) are networks that connect storage arrays to servers providing high-speed access to data using protocols such as Fibre Channel, iSCSI, and Fibre Channel over Ethernet. SANs are not covered in ICND1 or ICND 2.
LANs provide high-speed connections to end users and are relatively easy to maintain. This section provides an overview of LAN technologies as well as Cisco IOS features, enhanced IOS editing commands, and basic Cisco router and switch configuration.