Internetwork Operating System IOS

Router Theoretical Image 

IOS is Cisco's internetwork operating system. Just as PCs have operating systems and LANs have network operating systems, it is Cisco's belief that internetwork need their own operating systems. Cisco's goal was to create an operating system that could evolve as the network evolved.Cisco IOS is a multitasking operating system that is integrated with routing, switching, internetworking, and telecommunications functions.

It is a CLOSED SOURCE model that works only on CISCO devices. It's a command line interface hence can be  difficult to those who love to work on gui.though i personally never had any problem in working as the commands are easy to remember and execute. the Current version of IOS is 15.2(4)M2

Now as the IOS is present on the devices ,they can be as accessed by connecting a terminal or PC to a console port on a networking device. A terminal emulation package or Telnet is used to access the IOS software.

NAMING CONVENTION OF IOS FILES

Whenever " show flash " command is executed on privilege Mode you will find something like this
c2600-ik9s-mz.121-3.T.bin

• c2600 --- denotes the CISCO hardware
• ik9s-- feature supported
• m- indicates the memory location
• z-- show the compression technique used
• 121--Maintenance release
• 3-- individual release
• T-- train Identifier

DIFFERENT TYPES OF FLASH MEMORY LOCATIONS
   

Code	Location
F	IN FLASH
M	IN RAM
R	IN ROM
L	LOCATED AT RUN TIME

DIFFERENT TYPES OF COMPRESSION

CODE	COMPRESSION
Z	IN ZIP
X	IN MZIP
W	IN STAC COMPRESSION

All the information left, will be discussed in detail in the future Blogs..
Till then bye

keep Looking...

OSI Layers

In the last blog , we saw what the OSI Layers .Now its time to see what each layer is ,in short

A) Application Layer-It is employed in software packages which implement client-server software. When an application on one computer starts communicating with another computer, then the Application layer is used.

B) Presentation Layer-This provides function call exchange between host operating systems and software layers. Mostly dealing with compression ,encryption and decryption

C) Session Layer-The Session layer defines how data conversations are started, controlled and finished. It allows to create dialog between the systems  .

D) Transport Layer -  Ordering and reassembling of packets that may have been broken up to travel across certain media. It guaranties that the packet reached the destination successfully.

E) Network Layer- Mostly, the routing of packets is done here. Responsible for the delivery of packets end to end and implements a logical addressing scheme to help accomplish this.

F) Data Link Layer - Its divides the packet into frames and provide error correction by adding a trailer bit to the frame.

G) Physical Layer--This layer deals with the physical aspects of the media being used to transmit the data. Deals with the conversion of data bits into electric signals , their transmission and synchronization .

This can be easily memorized by 

" ALL PEOPLE SEEMS TO NEED DATA PROCESSING"

hope u understood and Best of Luck.

keep looking....

Network Interface Controller/Card (NIC)

NIC or network interface card or network adapter, LAN adapter is an important  hardware requirement for connectivity . Actually this interface  card provides us the 'gateway' through which data from one computer A can be transfered to another computer B. Its somewhat the  same as normal gate that we use in daily life to enter and exit.
A NIC technically is network adapter hardware in the form factor of an add-in card such as a PCI or PCMCIA card. Its actually a stick( looking somewhat like ram) and is mostly having an RJ45 connector at their one end.( u can see it at the back of ur laptop or PC..its where ur Ethernet wire is attached). Here is an image of what NIC looks like:

NIC is OSI layer 2 device (DATA LINK LAYER U can see this for more osi blog) . its consist of factory fitted 48bit address similar to that of ip address, here its called the MAC address or the Media Access Control address which is in .human-friendly form, is represented in  six groups of two hexadecimal digits, separated by hyphens (-)  or  colons (:), in transmission order.
For example ,consider the following

• 01-23-45-67-89-ab

•  01:23:45:67:89:ab

•  0001.4202.8360

the last one is not used much now days.

Basics Of Networking

Hey guys, this is the first time i m blogging and would like to start by talking about networking. What is  networking ,what u require for networking and few interesting  facts about  it...
So lets begin.

What is networking ??

In the world of computers, networking is the practice of linking two or more computing devices together for the purpose of sharing data. Networks are built with a mix of computer hardware and computer software.In easy words , what we are trying to do is that we want computer A to send a file to computer B ,so that i can be view over there.But we can use storage devices for this purpose.But what if  A is in C.A and B in Delhi. Its for this we need a system through which we can send the data while  maintaining its integrity ,authenticity and prevent manipulation  ..
Hardware  requirements are as follow :-

• computer /laptops ( at least two of them)
• NIC ( network interface card)
•  Connecting wires( a large variety is available)
• IOS (Internetwork Operating System)
• Topology used to connect the systems
• ID numbers,that identify two systems( usually called ipv4 ,ipv6)

Another important question 

Why do we require networking?? 

The answer is very interesting.

1. sharing of info/data  that is required while working on the a project
2. individual software cost is higher than that of  network softwares
3. reducing the number of hardware ( using  a single printer /fax for, say, 100 computers)
4. this is one of the most basic reason why students like us think of networking..( actually even i started it because of it)..Its Gaming ...

In the next blog i will tell u  about NIC and Connecting wires, i will also be telling about  the OSI Model and few other things...


Keep looking ..