Configuration Sub modes and Contexts

In Cisco IOS, there are several configuration modes that allow users to configure different parts of the network device. These modes are known as sub modes or contexts, and they are accessed from the global configuration mode using specific commands.

Here are some of the most common configuration sub modes and contexts:

Interface configuration mode: This mode is used to configure the physical and logical properties of a network interface, such as IP address, subnet mask, duplex mode, speed, and VLAN membership. It is accessed from global configuration mode using the “interface” command, followed by the interface type and number.

Line configuration mode: This mode is used to configure the properties of a console or VTY line, such as login authentication, timeout values, and logging. It is accessed from global configuration mode using the “line” command, followed by the line type and number.

Router configuration mode: This mode is used to configure the global properties of a router, such as hostname, domain name, and routing protocols. It is accessed from global configuration mode using the “router” command, followed by the routing protocol name.

VLAN configuration mode: This mode is used to create, modify, or delete VLANs on a switch. It is accessed from global configuration mode using the “vlan” command, followed by the VLAN number.

DHCP pool configuration mode: This mode is used to configure DHCP settings for a specific IP address pool. It is accessed from global configuration mode using the “ip dhcp pool” command, followed by the pool name.

Access list configuration mode: This mode is used to configure IP access lists that control traffic flow into or out of a network. It is accessed from global configuration mode using the “access-list” command, followed by the access list number or name.

Each configuration sub mode or context has its own set of commands that can be used to configure specific parameters or settings. Once the configuration is complete, the changes can be saved to non-volatile memory using the “write” command, which saves the configuration to the startup-config file.