ROUTER MODES
The Cisco IOS command-line interface (CLI) is the primary user interface used for configuring, monitoring, and maintaining Cisco devices. This user interface allows you to directly and simply execute Cisco IOS commands, whether using a router console or terminal, or using remote access methods.
Base command modes are used for navigating the CLI and performing basic router startup, configuration, and monitoring tasks
The following are the explanation of the modes
User EXEC Mode
The default command mode for the CLI is user
EXEC mode. The EXEC commands available at the user EXEC level are a
subset of those available at the privileged EXEC level. In general, the
user EXEC commands allow you to connect to remote devices, change
terminal settings on a temporary basis, perform basic tests, and list
system information. The prompt for user EXEC mode is the name of the
device followed by an angle bracket:
Router>. Privileged EXEC Mode
Privileged EXEC mode is password protected, and allows the use of all EXEC mode commands available on the system. To enter privileged EXEC mode from user EXEC mode, use the enable command. Privileged EXEC mode allows access to global configuration mode through the use of the enable command. The privileged EXEC mode prompt consists of the devices's host name followed by the pound sign:Router# .
Global Configuration Mode
Global configuration commands generally apply
to features that affect the system as a whole, rather than just one
protocol or interface. You can also enter any of the specific
configuration modes listed in the following section from global
configuration mode.
To enter global configuration mode, use the configure terminal privileged EXEC command. The router prompt for global configuration mode is indicated by the term config in parenthesis: Router(config)#NOTE: All routers has three major modes as shown above. When a router is switched on it displays the message"Would you like to make initial configuration then dialog [yes/no]? choose No and press enter. The diagram below shows steps to be followed
ROUTER MEMORY
Router has four types of memory:-
1.ROM
ROM is read-only memory available on a router's
processor board. The initial bootstrap software that runs on a Cisco router is
usually stored in ROM. ROM also maintains instructions for Power-on Self Test (POST) diagnostics. For ROM
Software upgrades, the pluggable chips on the motherboard should be replaced.
2. RAM(Rondom Access Memory):RAM is very fast memory that loses its information when the router is shutdown or restarted. It stores the running Configuration of Router. This stores the content Templary on the router.OR. RAM is used to hold running Cisco IOS Operating System, IOS system
tables and buffers RAM is also used to store routing tables, keep ARP
cache, Performs packet buffering (shared RAM). RAM Provides temporary
memory for the router configuration file of the router while the router
is powered on.
RAM Stores running Cisco IOS Operating
System, Active program and operating system instructions, the Running
Configuration File, ARP (Address Resolution Protocol) cache, routing tables and
buffered IP Packets.
3. VRAM(Non Volatile Ram): It stores the start up Configuration file of Router. It also stores the content permanently in the router. This is the configuration file that IOS reads when the router boots up.
It is extremely fast memory and retains its content when the router is
restarted.
4. Flash Mempry: Flash memory is an Electronically Erasable and Re-Programmable memory
chip. The Flash memory contains the full Operating System Image (IOS,
Internetwork Operating System). This allows you to upgrade the OS
without removing chips. Flash memory retains content when router is
powered down or restarted. Or It stores the IOS in the Router. IOS is the operating system for Routers.
NB:
To view to the content Of RAM a router has use the following command
On Router: Type #show run
To view to the content Of NVRAM a router has use the following command
On Router: Type #show start