COMPUTER NETWORKS

CREATED BY:

USMAN SHAFIQ

WALEED ZAFAR

FAHAD NADEEM

SHEHROZ KHAN

CONTENTSINTRODUCTIONCOMPUTER NETWORKTYPES OF NETWORKCLASSIFICATION OF NETWORK ARCHITECTURE

INTRODUCTION A computer network is a telecommunications network that allows computers

to exchange data. The physical connection between networked computing devices is

established using either cable media or wireless media. The best-known computer network is the internet.

COMPUTER NETWORK A collection of computing devices that are connected in various ways

in order to communicate and share resources. Usually, the connections between computers in a network are made

using physical wires or cables. However, some connections are wireless, using radio waves or

infrared signals.

TYPES OF NETWORK Based on the size and the coverage

area, networks are categorized into the following types:

Personal Area Networks (PANs) Local Area Networks (LANs)Metropolitan Area Networks (MANs)Wide Area Networks (WANs)

PERSONAL AREA NETWORKS (PANs) A personal area network (PAN) is a computer network used for communication

among computer and different information technological devices close to one person.

Is a small network established for communication between different devices, such as laptops, computers, mobiles, and PDAs.

A pan may include wired and wireless devices. The reach of a pan typically extends to 10 meters.

LOCAL AREA NETWORK(LANs) A local area network (LAN) is a network that connects computers

and devices in a limited geographical area such as a home, school, office building, or closely positioned group of buildings.

Each computer or device on the network is a node. Wired LANs are most likely based on Ethernet technology.

LOCAL AREA NETWORK

HISTORY

The increasing demand and use of computers in universities and research labs in the late 1960s generated the need to provide high-speed interconnections between computer systems.

A 1970 REPORT FROM THE LAWRENCE RADIATION LABORATORY DETAILING THE GROWTH OF THEIR "OCTOPUS" NETWORK GAVE A GOOD INDICATION OF THE SITUATION.

OCTOPUS NETWORK’S FIGURE

CABLES THAT ARE USED IN IN LOCAL AREA NETWORK

Early LAN cabling had generally been based on various grades of coaxial cable.

Shielded twisted pair was used in IBM's Token Ring LAN implementation.

CABLES THAT ARE USED IN IN LOCAL AREA NETWORK

But in 1984, StarLAN showed the potential of simple unshielded twisted pair by using Cat3 cable—the same simple cable used for telephone systems.

This led to the development of 10-Base-T (and its successors) and structured cabling which is still the basis of most commercial LANs today.

CABLES THAT ARE USED IN IN LOCAL AREA NETWORK

Fiber-optic cabling is common for links between switches, but fiber to the desktop is uncommon.

TECHNICAL ASPECTS

Network topology describes the layout of interconnections between devices and network segments.

At the Data Link Layer and Physical Layer, a wide variety of LAN topologies have been used, including ring, bus, mesh and star, but the most common LAN topology in use today is switched Ethernet.

TECHNICAL ASPECTS

At the higher layers, the Internet Protocol (TCP/IP) has become the standard, replacing NetBEUI, IPX/SPX, AppleTalk and others.

Simple LANs generally consist of one or more switches. A switch can be connected to a router, cable modem, or ADSL modem for Internet access

WLAN (WIRELESS LOCAL AREA NETWORK)

A WLAN is a wireless computer network that links two or more devices using a wireless distribution method within a limited area such as a home, school, computer laboratory, or office building.

WLAN (WIRELESS LOCAL AREA NETWORK)

Most modern WLANs are based on IEEE 802.11 standards, marketed under the Wi-Fi brand name.

Wireless LANs have become popular in the home due to ease of installation, and in commercial complexes offering wireless access to their customers; often for free.

WHAT IS IEEE 802.11? IEEE 802.11 is a set of media access control (MAC) and

physical layer specifications for implementing wireless local area network (WLAN) computer communication in the 2.4, 3.6, 5 and 60 GHz frequency bands.

VIRTUAL LOCAL AREA NETWORK

A VLAN allows several networks to work virtually as a LAN.

One of the most beneficial elements of a VLAN is that it removes latency in the network, which saves network resources and increases network efficiency.

VLAN TRUNKING PROTOCOL

(VTP) is a Cisco proprietary protocol that propagates the definition of Virtual Local Area Networks (VLAN) on the whole local area network.

VTP carries VLAN information to all the switches.

WHY USE VLAN? To create more flexible designs that group users by

department, or by groups that work together instead of by physical location.

To segment devices into smaller LANs (Broadcast Domains) to reduce overhead caused to each host in the LAN.

WHY USE VLAN? To reduce the workload for the Spanning Tree Protocol

(STP) by limiting a VLAN to a single access switch.

To ensure better security by keeping hosts that work with sensitive data on a separate VLAN.

TYPES OF VLAN STATIC VLAN.

TYPES OF VLAN Dynamic VLAN.

METROPOLITAN AREA NETWORK (MAN)

It is relatively larger than LAN and extends across a city or a metropolitan.

It is created by connecting two or more LANs located at different locations in a city.

EXAMPLE OF MAN• The best example is television cable network available in many

cities.

STANDARD OF MAN DQDB, Distributed Queue Dual Bus, is the metropolitan area

network standard for data communication. It is specified in the IEEE 802.6 standard. The reach of a MANs typically extends up to 20 miles (30 km)

long. A MANs operate at speeds of 34 to 155 Mbit/s.

WHY USE MAN? To Links between LANs with Cables and Wireless

media like microwaves, radio waves, or infra-red laser links.

WHAT IS BMAN?

BMAN (Broadband Metropolitan Area Network) is a telecommunications service from Sprint in the U.S.

WHAT IS BMAN? BMAN provides corporate users in a metropolitan area with

broadband access to the internet on optical fiber lines in a system that preserves a connection even when one line is cut or fails.

Using existing and supplemented infrastructure, BMAN uses a series of interlocking rings so that a connection can be restored within 60 milliseconds if a single line goes down.

WIDE AREA NETWORK(WANs)

A wide area network (WAN) is a computer network that covers a large geographic area such as a city, country, or spans even intercontinental distances.

Wide Area Network

A WAN uses a communications channel that combines many types of media such as telephone lines, cables, and air waves.

Wide Area Network A WAN often makes use of transmission facilities provided by

common carriers, such as telephone companies.

EXAMPLE OF WAN

One of the most prominent examples of the existing wans is the Internet.

WANLeased Lines

WANs are often built using leased lines. At each end of the leased line, a router connects the LAN on

one side with a second router within the LAN on the other. Leased lines can be very expensive.

Circuit Switching and Packet Switching

WANs can also be built using less costly circuit switching or packet switching methods.

WAN

CLASSIFICATION OF NETWORK ARCHITECTURE

The architecture of a network is a logical design that determines how the devices in the network communicate. The commonly used architectures for computer networks are:

Client-server architecture. Peer-to-peer architecture. Hybrid architecture.

CLIENT-SERVER ARCHITECTURE On a network built using the client-server

architecture, the devices communicate to other devices through a central computer referred to as a server.

The server is a terminal with high processing power, which provides services for the other computers on the network.

The client is a terminal that accesses the resources available on a server.

PEER-TO-PEER ARCHITECTURE On a network built using the peer-to-peer architecture, no

specific distinction exists between a client and a server. Any node can provide a service as well as send a  request for

a service from another node on the network. The peer-to-peer network architecture allows sharing of

resources, data, and users. Each node on the network has full control over the  network

resources.

Hybrid Architecture A hybrid, in general, is a composition of two different

types of elements. A hybrid network architecture is created to get the

benefits of both, the peer-to-peer and the client-server architectures, in a network.

REFERENCES

http://en.wikipedia.org

http://www.networkcomputing.com

http://www.networkworld.com

http://www.entrecomputer.com

Computer Networks(Andrew S.Tanenbaum)

Data & Computer communications(William Stallings)

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