09-04-2012, 04:57 PM
Introduction to Routers
introduction to routers.ppt (Size: 1.04 MB / Downloads: 92)
Router
Works at Layer 3, Network Layer (IP) in an intelligent manner.
Can connect Different Network segments, if they are in the same building or even on the opposite side of the globe.
Work in LAN, WAN environments.
Allow access to resources by selecting the best path.
Change packets size and format to match the requirements of the destination network.
Hardware Components
There are 7 major hardware components of a router:
CPU
RAM
NVRAM
Flash
ROM
Console
Interfaces
CPU
CPU performs functions just as ordinary PC.
It executes commands given by the IOS.
RAM
Hold the ARP cache, fast-switching cache and queues.
Store routing tables, performs packet buffering,
It also provides temporary memory for the configuration file of the router while the router is powered on.
FLASH
it saves your configuration
It holds the Cisco IOS image file, as well as backups
ROM
It holds information about the systems hardware components
INTERFACE
provide connectivity to LAN, WAN, and Console.
Software Components
As with a computer, A router or switch can not function without an operating system.
Cisco internetwork Operating System (IOS) is the software that controls the Routing and Switching Functions of internetworking devices.
Establish a Console Session
To establish a Hyper Terminal Session
Connect the terminal with an RJ-45-to-RJ45 Rollover cable or
RJ45-to-DB-9 or
RJ45-to-DB-25 Adapter
IOS Command Modes
User EXEC mode
Privileged EXEC mode
Global configuration mode
Interface configuration mode
Router configuration mode
Standard ACL
Filter packets on basis of source IP address
Access list no. {0-99}
Standard ACL is always applied at destination.
Standard Access List Configuration Syntax