172 Using the CLI1 default Po1-48, DefaultGi1/0/1-24Example #3CLI Command ModesSince the set of CLI commands is very large, the CLI is structured as acommand-tree hierarchy, where related command sets are assigned tocommand modes for easier access. At each level, only the commands relatedto that level are available to the user and only those commands are shown inthe context sensitive help for that level.In this guide, commands are organized into three categories:• Layer 2 (Data Link Layer) commands• Layer 3 (Network Layer) commands• Utility CommandsLayer 2 (Data Link Layer) describes the logical organization of data bitstransmitted on a particular medium. This layer defines the framing,addressing and checksumming of Ethernet packets.Layer 3 (Network Layer) describes how a series of exchanges over various datalinks can deliver data between any two nodes in a network. This layer definesthe addressing and routing structure of the Internet.Utility describes commands used to manage the switch.Commands that cause specific actions to be taken immediately by the systemand do not directly affect the system configurations are defined at the top ofthe command tree. For example, commands for rebooting the system or fordownloading or backing up the system configuration files are placed at thetop of the hierarchy tree.Commands that result in configuration changes to the switch are grouped ina Configuration sub tree.There are levels beneath the Configuration mode for further grouping ofcommands. The system prompt reflects these sub-Configuration modes.All the parameters are provided with reasonable defaults where possible.
