CISCO IOS– CISCO IOS stands for International Operating System.
CISCO IOS is a type of Os which install Cisco routers and Switches. It is propriety solution of CISCO.
The First IOS developed in 1986 by ‘WILLIAM YAGARS‘ It is responsible for—
- Carry Network protocol and function.
- Provide security.
- Provide High-Speed Network Traffic.
These are different kinds of IOS version developed by CISCO. Its latest version is 150.
The router is a layer 3(Network Layer) device, which connects two or more different network. It also Provides the best route between source and destination.
COMPONENT OF CISCO IOS ROUTER–
- EXTERNAL COMPONENTS- These are different kinds of an external component of the router.
- SERIAL PORT– Router to WAN connectivity.
- ETHERNET PORT–LAN connectivity.
- BRI–Basic Rate Interface(ISDN Connectivity).
- AUI–Additional LAN Port
- AUX–Auxillary Port(WAN Connectivity).
- CONSOLE PORT–To configure the Router/switch from Computer.
2. INTERNAL COMPONENTS-
- MOTHERBOARD– Gives a platform to connect all the devices.
- ROM–(Read Only Memory) It has four components.
- RAM– It is a volatile memory, which holds the only active configuration of the router. It also holds routing table and ARP table.
- NV-RAM–It is a non-volatile memory, which stores startup configuration.
- FLASH MEMORY– It contents IOS of the router.
CONFIGURATION REGISTRY VALUE–
It is a 16-bit value which is represented in the hexadecimal format that tells the router from where it will boot.
There are four type of REGISTRY VALUE–
- 0*2100–This value tells the router to boot from ROM MONITOR MODE(SAFE MODE).
- 0*2101–This value tells the router to boot from mini IOS.
- 0*2102–This value tells the router to boot from FLASH with NVRAM/startup configuration. It is the default configuration REGISTRY VALUE.
- 0*2142–This value tells the router to boot from FLASH, but ignore NVRAM configuration (Used for Password breaking).
ROUTER POST SEQUENCE–
- BOOT STARTUP