Some Show Commands

• RTR# show running-config          
• RTR# show startup-config
• RTR# show flash
• RTR# show version

Magic Keys for help:

1. [tab] : Completes the command.
2. ? : Displays the command that are usable in the required mode.

Initial Configurations

Setting Hostname:
Router(Config)# hostname RTR
RTR(Config)#

Putting IP address to an interface:
RTR(Config)# interface f0/0             -----> 0 = Zero
RTR(Config-if)# ip address 192.168.1.1 255.255.255.0
RTR(Config-if)# no shutdown     ----> Activating the interface
RTR(Config-if)# exit
RTR(Config)#

Configuring Console:
RTR(Config)# line console 0                  -----> 0 = Zero
RTR(Config-line)# password console
RTR(Config-line)# exit

Securing VTY ports:
RTR(Config)# line vty 0 4
RTR(Config-line)# password telnet
RTR(Config-line)# exit

Securing Priviledge Mode:
RTR(Config)# enable secret cisco
or, RTR(Config)# enable password cisco

Saving Router's Configuration:
RTR# copy running-config startup-config
or,
RTR# write
or,
RTR# write memory

Modes of router

1) User executive mode:
" Router> "
Commands eg. telnet, traceroute, ping





2) Privilege executive mode:
Router> enable <enter>

" Router# "

3) Global Configuration Mode:
entire configuration is done in this mode
Router# config terminal <enter>
" Router(Config)# "

Physical Connection

start>programs>accessories> communication>hyperterminal

or PuTTY / teraterm

Boot Sequence

Boot Sequence:
i.     POST (Power-On Self Test)
ii.     ROM
iii.     Flash (IOS) (flash ----> TFTP)
iv.     NVRAM (Loads configuration)
v.     In case no configuration file, goes to setup mode.

CISCO Router Components

Router Components:
ROM     : Contains bootstrip
Flash    : Store CISCO IOS
NVRAM     : Non Volatile Random Access Memory: Stores startup-config
RAM     : Stores running Config

IP Adressing

- It is a 32-bit addressing scheme.
- Each octet is separated by periods.             A        B     C       D
                                                                 E.g.:  192 . 168 . 10   .  10
                                                                 S.M:  255 . 255 . 255 .  0
A / B / C / D =  8 - Bit

CSMA/CD : Day 3

1. Carrier Sense Multiple Access / Collision Detection:

     It is the working principle of Ethernet.

2. Communication:

• Half Duplex: Either send or receive. E.g. Wireless, hub
• Full-Duplex: Both send & receive at the same time. E.g. Modern switch.

3. MAC Address:

• 48 - bit physical address



MAC Address

• First 24-bit is known as OUI (Organizationally Unique Identifier)

 

4. Cabling Standard:

• Standard is maintained by TIA / EIA
• Auto-MDX is a feature which can accept both serial and crossover cable.

5. Broadcast Domain:

•  Area of the broadcast up to where the broadcast can go.
• Every port of a router is a broadcast domain.

6. Collision Domain: 

• Every switch-port is a collision domain.
• Every switch-port separates a collision domain.