INTRODUCTION TO NETWORKING

INTRODUCTION TO NETWORKING

COMMUNICATION MODES

1. Simplex (one way communication)
2. Half Duplex (two way communication but not simultaneously)
3. Full Duplex (two way communication simultaneously)

Duplex and Speed Mismatch Issue

This issue creates if any switch and NIC not have the same setting, due to this packets starts to drops.
Syntax:
Switch (config) #int fa0/1
Switch (config-if) #duplex full
Switch (config-if) #speed 100

Manufacturing Terms of Cisco

EOS (End of sale)
It is use for such product whose manufacturing become terminates, but is warranty is valid due to sold in market before.
EOL (End of life)
It is use for such product whose manufacturing as well as warranty become stop. So the Cisco does not support such device and consider as garbage.
IOS (Internetwork operating system)
It is the operating system use by router or layer-3 switches.
Examples: version 12.3, 12.2, 12.1, 12.0, 11.3

SWITCH

It is a device use for networking (LAN), they based on specific chip that is represented by ASIC (Application specific Integrated chip).

Modular Switch

Such switches in which we can add the additional cards when need.
Layer-2 Switches
Such switches which only do switching.
Examples: (CISCO Express 500) and (CISCO Catalyst 2940, 2950, 2960 series).
Layer-3 Switches
Such switches which can do switching as well as routing.
Example: (CISCO Catalyst 3550, 360, 370, 4500, 6500 Series).

ROUTER
It is a internetworking device (WAN), they based on microprocessor.

Cisco Switch And Router Hardware Components
1) RAM 2) NVRAM 3) FLASH 4) ROM

RAM
It is such memory where the running configuration (user configuration) exists.

NVRAM
It is such memory where the data stored permanently and this configured data is refer by the term “start-up-configuration”.

FLASH
It is such memory where the IOS present and here the data also present permanently.

ROM
It is such memory where all modes of switch or router exist, these modes called the ROM monitor mode; they come after the IOS load.

Switches and Routers boot sequence

• At Post point, the hardware is check.
• At Flash point, IOS files or IOS check.

Best Regards, 

S. N. Jafar