Routers and its discription

Routers and its discription

Components of a router

 

COMPUTER	ROUTER
HARDDISK	FLASH
RAM	RAM
NVRAM	NVRAM
ROM	ROM

FLASH
     It is similar to the hard disk of your computer it is EEPROM.(Electrical Erasable Programmable Read Only Memory)
     It contains the copy of IOS (Internetworking Operating System)

RAM
     Random Access Memory
     It is volatile Memory
     In case of any sudden power failure all the changes made but not saved get lost.
     It contains the running configuration file.
o    Running Configuration
§    It is the configuration that has been changed but not saved.
NVRAM
     Configuration file is always in NVRAM.
     In case of which all changes made and saved will not get lost.
     It contains the startup configuration file.
o    Startup configuration
§    It is configuration that has been changed as well as saved.

ROM

     POST (Power On Self Test). it is used for hardware testing.
     BOOT STRAP it’s specify the router from where to load the operating system in the router.
     MINI IOS
o    It is the mini IOS.
o    Mini IOS is the minimum set of driver that is required to boot the router.

Router Booting Sequence

1.    POST
2.    BOOT STRAP
a.    Its specify the router from where to load the IOS.
3.    By default the router will load the IOS from flash to RAM.
4.    Then the router will look for the saved configuration as start up configuration in NVRAM if it gets this configuration then it will load with that configuration else it will try to go into the setup mode.
a.    Would you like to enter into initial configuration Y/N.?

DYNAMIC SYSTEM CONFIGURATIONP

ART OF A ROUTER

There are two main part of the router
     LINES
     INTERFACES
INTERFACES
    Interfaces are used to connect the router with the LAN or WAN.
    Over interface we specify the IP addresses
Type of the interfaces
    Ethernet port (used to connect the router with a computer)
    Serial port (used to connect the router with other router)
    BRI (Basic Rate Interface Port) used for WAN connectivity.
LINES
    Lines are used to get the access of a router in order to configure the router.
    Over line we specify the login and password. Always firstly we specify the   
             Password and then we enter the login. Login command activates the line only.
Type of the lines
    Console line
    Vty line (virtual type)
    Auxiliary
PORTS
Ethernet ports
it is an interface that is used to make your router a member of LAN. It is used for LAN connectivity.

Two types of Ethernet ports:
1.    RJ 45 female port
2.    AUI (Attachment Unit Interface) 15 pin model. In case of AUI Ethernet transceiver will be used. AUI is always simple Ethernet port. i.e. 10 Mbps.

Three categories of the Ethernet port e0, e1, and e0/0
1.    Simple Ethernet  port  10 Mbps
2.    Fast Ethernet port 100 Mbps
3.    Gigabit Ethernet port  1000 Mbps

Notes
    The router Ethernet port address is the default gateway for all the systems that are member of that LAN.

Console port:
·    It is line that is used to get the access of a router in order to configuration it locally.
·    Console wire or roll over wire is used for this purpose.
·    One end of this console cable is male RJ-45 and other end is com(female) or serial of (9 pin connector)
·    It is RJ-45 female ports.

BRI port
·    Basic Rate Interface
·    It is port where we connect our dedicated ISDN line to our routers.
·    It is a RJ-45 female port.


Telephone line    ISDN(Integrated Service Digital Network)      
It is an analog line     It is a digital line      
It provides only audio support    It provides both audio , video and data       
It provides to the max of 56 kbps.    It has two B and one D channel. Each B channel is of 64 kbps and
D is of 16 kbps. i.e. total 144 kbps.   


Auxiliary port:

·    It is a line through which we can get access of router in order to configure it and that is also remotely.
·    It is port where we connect our dedicated telephone to our router.

VTY port
·    Virtual type
·    It is a logical part that does not exist physically.
·    It is used to activate telnet service over the router for that purpose we have to set login and password over the vty line.
·    Line vty 0 4
·    Password
·    Login

Serial port
·    It is the port where we connect either two routers directly or remotely.
·    It is used for WAN connectivity.
·    It uses v.35 cable.
·    Locally when two router are directly connected using a serial cable.
·    Two type of serial port
o    60 pin modular port (DB 60)
o    Smart serial
·    DB 60
o    It is a 60 pin modular port it is always IT( 1 T mean one terminal)
·    Smart serial
o    Latest and compact
o    It can be 1T as well as 2T.
o    Two categories of serial interface card.
§    WIC 1T WAN interface Card 1 terminal.
·    Only DB60 and smart serial

§    WIC 2T : WAN Interface Card 2 terminal  ( means two port on a single interface like USB interface)
·    Only smart serial.

Serial cable types
    End to end DT/DC cable – 60 pin or smart serial.
One end of the serial cable is DTE (Data Terminating Equipment)
Other end of the serial cable is DCE (Data Circuit terminating Equipment)
DCE is always females. We have to set the clock rate on the 64000.

Different modes of operation

1.    User Execution Mode
a.    VTY
b.    CONSOLE
c.    AUXILIARY
By using enable command we can enter in the privilege mode.
2.    Privileged mode
a.    We can copy or save the configuration in this mode
b.    All the command of show is executed in this mode.
3.    global configuration mode
a.    We can change the configuration in this mode.

User execution mode
     It is very limited type of mode, in it neither we can see or nor we can change the router configuration.
     Command used in this mode are
a.    Ping
b.    telnet
c.    traceroute
     There are two type of the password.
a.    Simple enable password
·    Plain text password
·    Priority low
·    To set password command is
1.    enable password (password)

note :à this simple password can be seen by show running-config command. Because it is not encrypted.
b.    Enable secret password
·    Encrypted form
·    High priority
·    To set secret password command is
1.    enable secret (password)

note :-- this password never be seen by the show running-config command. Because it is encrypted.
c.    Both passwords never are same.


Privileged mode


It is a mode where we can see or save the router configuration. But we cannot change the router’s configuration.
Commands used in this mode are
Show commands are used to see the configuration.
Copy commands are used to save the router configuration.
Debug commands are used to see the router backend processing to the front end.

Global configuration mode
We can enter in this mode by using the command config terminal  or configure
It is the mode where we can change the router’s configuration.
The commands used at this mode are
We can change or set the hostname of the router.
We can change or set the enable secret password
We can set the banners.
Line configuration mode
It is a mode where we can change the configuration relating to any specific line.
Commands used at this mode are
Login
Password

Interface configuration mode

It is a mode where we can change the configuration related to any interface
Commands used at these modes are

We can set the clock rate
We can change or set the IP address.
We can change the status of a specific interface