Chapter 1 - Introduction to Networking

UNIT 1

INTRODUCTION TO

NETWORKING

LEARNING OUTCOME

Student should be able to:

1. List advantages of networked computing relative to standalone computing.

2. Differentiate between peer-to-peer networks and client/server networks

3. Differentiate Local Area Network (LAN), Metropolitan Area Network (MAN), Wide Area Network (WAN)

WHAT IS NETWORKING?

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.

A network is nothing more than two or more computers connected to each other so that they can exchange information, such as email messages or documents or share resources, such as disk storage.

CHARACTERISTIC OF

COMPUTER NETWORK

http://www.functionx.com/networking/Lesson01.htm

NETWORKING

Advantages

A user can logon to a computer anywhere on the

network and access their

work files from the file

server.

Computers can be managed centrally - with the same

software installed on each

one.

Time - it is much faster to install an application once

on a network - and copy it

across the network to every

workstation.

Disadvantages

If something goes wrong with the file

server the whole

network.

The technical skills needed to manage a

network are much

higher than working on

a stand-alone

computer.

http://www.ictgnvq.org.uk/unit10/advantages_and_disadvantages.htm

NETWORK VS STAND ALONE

Advantages Sharing printers, plotters,

modems etc saves money and time.

Security - the Network Manager can allocate usernames and passwords to all users to try to prevent unauthorized access.

I is easy and convenient to monitor users for example websites visited or documents printed this can be done using software running on the server.

Disadvantages It can be frustrating to print to

a printer in another room and then find after a long trek that there is no paper in the printer!

Users may use up too much of the storage space and this may cause problems on the network.

Users may use too much bandwidth for example when listening to music files or watching video clips preventing others from using the network facilities properly.

http://www.ictgnvq.org.uk/unit10/advantages_and_disadvantages.htm

PEER-TO-PEER NETWORKS

(P2P)


(P2P) 1. The simplest form of a network.

2. Traditional p2p networks typically consist of two or more general purpose personal computer, with modest processing capabilities.

3. By default, no computer on a peer to peer has more authority than another.

4. However, each computer can be configured to share only some of its resources and prevent access to other resources.


(P2P) 1. Each computer holds its files and resources.

Other computers can access these resources but a computer that has a particular resource must be turned on for other computers to access the resource it has. For example, if a printer is connected to computer A and computer B wants to printer to that printer, computer A must be turned ON.

2. A Peer to peer capable network operating system, such as Windows 95, Windows 98 and Windows for Workgroups are usually the best choices for home and small office networks.

ADVANTAGES AND

DISADVANTAGES OF P2P

Advantages

Network is fast and simple to setup and

maintain.

Less expensive to set up and maintain than

other types of

networks.

No need for network administrator.

Disadvantages

Not secure enough. In simple installations, data and other resources shared by network users can be easily discovered and used by unauthorized people.

Not practical for larger computer.

Not flexible as network grows larger, adding or changing significant elements of the network may be difficult.

CLIENT-SERVER NETWORKS


A network that uses a server to enable clients to share data, data storage space, and devices is known as a client/server network.

Another way of designing a network is to use a central computer, known as a server, to facilitate communication and resource sharing between other computers on the network, which are known as clients.



Every computer on a client/server network acts as a client or a server. (It is possible, but uncommon, for some computers to act as both.)

Clients on a network can still run applications from and save data to their local hard disk. But by connecting to a server, they also have the option of using shared applications, data, and devices.


Clients do not share their resources directly with each other, but rather use the server as an intermediary through connectivity devices such as switches or routers.

Client-Server network operating systems, such as Windows NT and Novel NetWare are better for larger scale organizations that require fast network access for video, publishing, multimedia, spreadsheet, database, and accounting operations.

ADVANTAGES OF CLIENT-

SERVER NETWORKS

User logon accounts and passwords for anyone on a server-based network can be assigned in one place.

Access to multiple shared resources (such as data files or printers) can be centrally granted to a single user or groups of users.

Problems on the network can be monitored, diagnosed, and often fixed from one location.

ADVANTAGES OF CLIENT-

SERVER NETWORKS

Servers are optimized to handle heavy processing loads and

dedicated to handling requests from

clients, enabling faster response time.

Because of their efficient processing and larger disk storage, servers can

connect more than a handful of

computers on a network.

TYPES OF NETWORKS

LOCAL AREA NETWORK (LAN)


Supplies networking capability to a group of computers in close proximity to each other such as in an office building, a school, or a home.

A LAN is useful for sharing resources like files, printers, games or other applications. A LAN in turn often connects to other LANs, and to the Internet or other WAN.


Most local area networks are built with relatively inexpensive hardware such as Ethernet cables, network adapters, and hubs. Wireless LAN and other more advanced LAN hardware options also exist.

Specialized operating system software may be used to configure a local area network. For example, most flavors of Microsoft Windows provide a software package called Internet Connection Sharing (ICS) that supports controlled access to LAN resources.


The term LAN party refers to a multiplayer gaming event where

participants bring their own computers

and build a temporary LAN.

METROPOLITAN AREA

NETWORK (MAN)

METROPOLITAN AREA

NETWORK (MAN)

A metropolitan area network (MAN) is a computer network that usually spans

a city or a large campus. A MAN

usually interconnects a number of

local area networks (LANs) using a

high-capacity backbone technology,

such as fiber-optical links, and

provides up-link services to wide area

networks (or WAN) and the Internet.

METROPOLITAN AREA

NETWORK (MAN) The IEEE 802-2002 standard describes a MAN

as being :

A MAN is optimized for a larger geographical area than a LAN, ranging from several blocks of buildings to entire cities. MANs can also depend on communications channels of moderate-to-high data rates. A MAN might be owned and operated by a single organization, but it usually will be used by many individuals and organizations. MANs might also be owned and operated as public utilities. They will often provide means for internetworking of local networks.

WIDE AREA NETWORK (WAN)

WIDE AREA NETWORK (WAN)

A wide area network (WAN) is a computer network that covers a broad area (i.e., any

network whose communications links cross

metropolitan, regional, or national boundaries).

This is in contrast with personal area networks (PANs), local area networks (LANs), campus

area networks (CANs), or metropolitan area

networks (MANs) which are usually limited to a

room, building, campus or specific metropolitan

area (e.g., a city) respectively.

LEARNING OUTCOME


1. Explain client, server, workstation,

network interface card, network

operating system, node, connectivity

device, backbone, segment, topology

and transmission media.

2. Distinguish the computer network

topologies : bus, ring, star and hybrid.

ELEMENT IN CLIENT-SERVER

NETWORKS

ELEMENT

Client

Server

Workstation

Network Interface Card

Network Operating System

Node Segment

Backbone

Connectivity Device

Topology

Transmission Media


NETWORKS

Client

A computer on the network that request resources or services from another computer on a network.

Server

A computer on the network that manages shared resources among client.


NETWORKS Workstation A computer on which a person performs

everyday regular assignments. A workstation is primarily a personal computer (PC). It can also be a laptop. Almost any modern PC can be used as a workstation and participate to a network.

Network Interface Card (NIC) The device inside the computer that

connect a computer to the network.



NETWORKS Network Operating System (NOS)

The software that run on a server and enables the server to:

i. Manage data and other resources for a number of client.

ii. Ensure that only authorized users access the network.

iii. Control which type of files a user can open and read.

iv. Restrict when and from where users can access the network.

v. Dictate which rules computer to communicate.

vi. Supply application to clients.

A software that allows multiple computers to communicate, share files and hardware devices with one another.

Examples of network operating systems include Novell NetWare, Microsoft Windows NT, Microsoft Windows 2008 Server, Sun Solaris, Linux.


NETWORKS

Node

A client, server or other device that can

communicate over the network and that is

identified by a unique number, known as its

network address.

Segment

A part of network. Usually a segment is

composed of a group of nodes that use the

same communications channel for all their

traffic.


NETWORKS

Backbone

The part of a network (connection) to

which segments and shared devices

connect. A backbone is sometimes

referred to as a network of network because its role in interconnecting

smaller parts of LAN or WAN.


NETWORKS Connectivity Device

A specialized device that allow multiple networks or multiple parts of the networks to connect and exchange data. Examples : repeater, hub/switch, bridges, router, gateways.

Topology

The physical layout of a computer networks.

Transmission Media

The means through which data is transmitted and received. Examples : coaxial cable, STP, UTP, fiber optic.

Network Topology

BUS

STAR

RING

HYBRID

BUS

Each node (workstation, server, switch and etc) is connected to a single cable.

A signal from the source travels in both directions to all machines connected on the bus cable until it finds the intended recipient.

If the machine address does not match the intended address for the data, the machine ignores the data.

BUS

Alternatively, if the data does match the machine address, the data is accepted.

Since the bus topology consists of only one wire, it is rather inexpensive to implement when compared to other topologies. However to manage this network topology require higher cost.

BUS

What is the advantages of this topology?

Easy to connect a computer or peripheral to a linear bus.

Requires less cable length than mesh or star topologies.

It is cheaper than any other topologies.

BUS

What happen is the single cable fail or damaged?

Additionally, since only one cable is utilized, it can be the single point of failure. If the network cable breaks, the entire network will be down.

BUS

Others disadvantages of this topology?

Terminators are required at both ends of the backbone cable.

Addition of new devices requires modification or replacement of the backbone.

The managing cost of network is too high.

STAR

Each network host is connected to a central hub or switch with a point-to-point connection.

All traffic that traverses the network passes through the central hub.

The hub acts as a signal repeater.

STAR

The star topology is considered the easiest topology to design and implement.

What is the advantages of this topology?

Easy to install and reconfigure.

No disruptions to the network when connecting or removing devices.

Easy to detect faults and to remove parts.

Robustness, that is, if one link fails, only that link is affected, other links remain active.

STAR

The star topology is considered the easiest topology to design and implement.

What is the advantage of this topology?

An advantage of the star topology is the simplicity of adding additional nodes.

STAR

What is the disadvantage if this topology?

The primary disadvantage of the star topology is that the hub represents a single point of failure.

Requires more cable length than a bus topology.

More expensive than bus topologies because of the cost of the hubs and etc.

RING

A network topology that is set up in a circular fashion in which data travels around the ring in one direction and each device on the right acts as a repeater to keep the signal strong as it travels.

RING

Each device incorporates a receiver for the incoming signal and a transmitter to send the data on to the next device in the ring. The network is dependent on the ability of the signal to travel around the ring.

http://www.datacottage.com/nch/troperation.htm

RING

What is the disadvantage of

this topology?

The failure of one machine will cause

the entire network

to fail.

http://wiki.answers.com/Q/Advantages_and_disadvantages_of_topologies

HYBRID

Hybrid networks use a combination of any two or more topologies in such a way that the resulting network does not exhibit one of the standard topologies (e.g., bus, star, ring, etc.).

HYBRID

A hybrid topology is always produced when two different basic network topologies are connected. Two common examples for Hybrid network are: star ring network and star bus network

HYBRID

Star Ring Network

Star Bus Network

HYBRID

Advantages of this topology?

Can be designed in many ways for various purposes.

Provides better result according to the management.

Disadvantages of this topology?

Difficult to identify the problem if entire system is down.

Learning Outcome


1. Identify organization that set standards for networking : ANSI, EIA, TIA, IEEE, ISO, ITU, ISOC, IANA, ICANN.

2. Explain source, channel and destinations.

3. Explain rules of communications.

4. Explain message encoding, formatting, size, timing and patterns.

Information Search

Form group of 3 students.

You will be entering Poster Competition about the standards for networking:

1. ANSI (American_National_Standards_Institute) fares | faeez

2. EIA/TIA (Electronic_Industries_Alliance / Telecommunications Industry Association) eynani | leow

3. IEEE anselm | farhan

4. ISO (International_Organization_for_Standardization) amirul hakim | az-syafiz

5. ITU (International_Telecommunication_Union) walid | syahmi

6. ISOC (Internet_Society) kugendran | fauzie

7. IANA (Internet_Assigned_Numbers_Authority) khumuthavalli

8. ICANN nur hanani

EXERCISE

1. Draw a diagram showing three computer and one printer connecting to each other using: a. Bus topology

b.Star topology

c. Ring topology

2. One computer wants to send file to printer. By using the diagram you created in question one, draw the data path/route taken by this file for the three topology mention above.

PRINCIPLES OF

COMMUNICATION

Channel A distinct communication path between

two or more nodes, much like a lane is a distinct transportation path on a freeway.

Channels may be separated either logically (as in multiplexing) or physically (as when they are carried by separate wires).

SOURCE DESTINATION

Channel

PRINCIPLES OF

COMMUNICATION

The sender (source) who creates the message to be transmitted

A medium that carries the message. (channel)

The receiver (sink) who receives the message. (destinations).

SOURCE DESTINATION

Channel

RULES OF COMMUNICATION

Establish a link Issue a command and command qualifier

Send, receive

Acknowledgment of command Acknowledgement field in Ethernet frame

Dissection messages Packet, frame

Error detection and correction cyclic redundancy check (CRC)

Termination of transmission

EXAMPLE

TERMINOLOGIES IN NETWORK

1. Message Encoding

Example: Specific Area Message Encoding or SAME is the protocol used to encode the Emergency Alert System (EAS) and NOAA Weather Radio in the U.S

2. Message Formatting

Example: ICMP message use in ping, tracert

3. Message Size

Example: Thus smtp2.example.com declares that it will accept a fixed maximum message size no larger than 14,680,064 octets

TERMINOLOGIES IN NETWORK

4. Message Timing

Example: ttl time to live

5. Message Patterns

A Message Exchange Pattern (MEP) describes the pattern of messages

required by a communications protocol to

establish or use a communication

channel.

Learning Outcome


1. Identify cards on expansion board inside a computer : PIC NIC, PIC Express NIC.

2. Identify cards installed to the computers bus externally : PCMCIA adapter, USB port, FireWire, Compact Flash NIC.

3. Identify On-board NIC.

4. Identify NIC.

NETWORK INTERFACE CARD

(NIC)

Various types of Network Interface Card :

1. Cards on an expansion board inside a computer (PCI NIC, PCI Express NIC)

2. Cards installed to the computers bus externally (PCMCIA adapter, USB port, Fire Wire, Compact Flash NIC)

3. On board NIC

4. Wireless NIC

NETWORK INTERFACE CARD

(NIC) A circuit board or chip, which allows the

computer to communicate to other computers on a Network for the purpose of sharing resources, information and computer hardware.

This board can be connected to a cable or other method of transferring data such as infra red.

Utilizing network cards to connect to a network allow users to share data such as companies being able to have the capability of having a database that can be accessed all at the same time, send and receive e-mail internally within the company, or share hardware devices such as printers.

PART OF NETWORK INTERFACE

CARD (NIC) CONNECTORS

Network cards have three main types of connectors. Below is an example of what a network card may look like.

BNC - As illustrated in the above picture, the BNC connector is a round connector which is used for Thinnet or 10Base-2 Local Area Network.

DB9 - DB9 connectors were commonly used before for serial peripheral devices like keyboards, mice, joysticks, etc.

In network it used in token ring topology network.


CARD (NIC)

RJ45 - Today, one of the most popular types of connections used with computer

networks. RJ45 looks similar to a phone

connector or RJ11 connector but is slightly

larger.


CARD (NIC)

LED -The LEDs indicates if it detects a network; generally by a green light

which may flash as it communicates,

and then a red light which indicates

collisions which will generally flash or

not flash at all.

TYPES OF NETWORK

INTERFACE CARD (NIC)

Installed on an expansion board inside a computer

PCI NIC

PCI Express NIC

TYPES OF NETWORK


Cards installed to the computers bus externally

PCMCIA Adapter

USB Network Adapter

FireWire Network Adapter

Compact Flash NIC

PCMCIA - Personal Computer

Memory Card

International Association is an industry organization best know

for developing a standard network

adapter using the PC Card form factor.

The PC Card form factor was designed for thinness, and PCMCIA is therefore

especially well suited for notebook

computers. Most notebooks contain

two PCMCIA slots that hold one or two

of these cards.

USB NETWORK

ADAPTER

FIREWIRE NETWORK ADAPTER

Compact Flash NIC

TYPES OF NETWORK


On-board NIC

TYPES OF NETWORK


Wireless NIC

Wireless PCMCIA network adapter Wireless PCI network adapter

Wireless USB adapter

Wireless Compact Flash network adapter

LAN CONNECTIVITY

HARDWARE Repeater

An electronic device that receives a signal and retransmits it at a higher level and/or higher power, so that the signal can cover longer distances.

To regenerate the signal when the signal received is weak or interference, this device will make a copy of bits to bits by the original signal strength.

Repeaters work with the actual physical signal, and do not attempt to interpret the data being transmitted, they operate on the Physical Layer, the first layer of the OSI model.

LAN CONNECTIVITY

HARDWARE Hub

An Ethernet hub, active hub, network hub, repeater hub or hub is a device for connecting multiple twisted pair or fiber optic Ethernet devices together and making them act as a single network segment.

Hubs work at the Physical Layer (Layer 1) of the OSI model

Active Hub is called multiport repeater. participate in collision detection, forwarding

a jam signal to all ports if it detects a collision.

LAN CONNECTIVITY

HARDWARE

Switch A network switch or switching hub is a

computer networking device that connects network segments.

The term commonly refers to a network bridge that processes and routes data at the Data Link Layer (Layer 2) of the OSI model.

Switches that additionally process data at the Network Layer (Layer 3 and above) are often referred to as Layer 3 switches or multilayer switches.

LAN CONNECTIVITY

HARDWARE

Difference between Hub & Switch

A switch learns which devices are connected to its ports and then forwards

on packets to the appropriate port only.

Hubs repeat everything they receive and resulting unnecessary traffic being sent to

all devices on the network.

LAN CONNECTIVITY

HARDWARE

HUB SWITCH

Hub is broadcasting device. Switch is point to point

communication.

Hub operates at physical layer. Switch operate at data link

layer.

Hub is not an intelligent service

(dummy device).

Switch is intelligent device.

Hub simply broadcast the

incoming.

Switch uses switching table to

find the correct destination.

Hub cannot be used as repeater. Switch can be used as a

repeater.

LAN CONNECTIVITY

HARDWARE Bridges

A network bridge connects multiple network segments at the Data Link Layer (Layer 2) of the OSI model.

Used to transmit data between networks that using the same protocol.

A bridge and switch are very much alike; a switch being a bridge with numerous ports.

Bridges can analyze incoming data packets to determine if the bridge is able to send the given packet to another segment of the network

LAN CONNECTIVITY

HARDWARE Router

A device that forwards data packets along networks. A router is connected to at least two networks, commonly two LANs or WANs or a LAN and its ISPs network. Routers are also located at gateways, the places where two or more networks connect.

Makes decisions on how to manage the contents of the frame based on protocol and network address.

Routers use headers and forwarding tables to determine the best path for forwarding the packets, and they use protocols such as ICMP to communicate with each other and configure the best route between any two hosts.

LAN CONNECTIVITY

HARDWARE

Router

A router is a networking device whose software and hardware are customized to

the tasks of routing and forwarding

information.

A router has two or more network interfaces, which may be to different

physical types of network (such as copper

cables, fiber, or wireless) or different

network standards

Works in Layer 3 OSI model

LAN CONNECTIVITY

HARDWARE

Gateway

A network gateway is an internetworking system capable of joining together two

networks that use different base protocols.

A network gateway can be implemented completely in software, completely in

hardware, or as a combination of both.

Depending on the types of protocols they support, network gateways can operate at

any level of the OSI model.

LAN CONNECTIVITY

HARDWARE Gateway

Connect two systems using different formatting, communications protocols, or architecture Repackage information to be read by another

system

Operates at multiple OSI Model layers

E-mail gateway Internet gateway LAN gateway Voice/data gateway Firewall

Learning Outcome


1. Install and configure NIC hardware

and software.

2. Illustrate repeater, hub/switch,

bridges, routers, gateways.

Learning Outcome


1. Build simple peer-to-peer network using TIA/EIA-568-A or TIA/EIA-568-B wiring standard.

2. Build simple LAN using two hosts and a switch.

3. Build network drive to share a file.

4. Assemble and configure a network printer in a simple LAN

http://en.wikipedia.org/wiki/American_National_Standards_Institute

http://en.wikipedia.org/wiki/Electronic_Industries_Alliance http://en.wikipedia.org/wiki/Telecommunications_Industry_Ass

ociation

http://en.wikipedia.org/wiki/Ieee http://en.wikipedia.org/wiki/International_Organization_for_Sta

ndardization

http://en.wikipedia.org/wiki/International_Telecommunication_Union

http://en.wikipedia.org/wiki/Internet_Society http://en.wikipedia.org/wiki/Internet_Assigned_Numbers_Auth

ority

http://en.wikipedia.org/wiki/Icann

Documents

Chapter 1 - Introduction to Networking