Networking BasicsNetworking Basics

Lesson 1

Introduction to Networks

Introduction to NetworksIntroduction to Networks

What is Networking?What is Networking? Networks EnvironmentsNetworks Environments

StandaloneStandalone

NetworkingNetworking LANs Vs WANsLANs Vs WANs

Network definitionNetwork definition

data network is a group of computers data network is a group of computers connected by a network medium. connected by a network medium.

The network medium carries signals The network medium carries signals between computers.between computers.

Signals reduce complex information to the Signals reduce complex information to the simplest possible form.simplest possible form.

Computers communicate by using a Computers communicate by using a language called a protocol.language called a protocol.

Protocol ServicesProtocol Services

Packet acknowledgmentPacket acknowledgment SegmentationSegmentation Flow controlFlow control Error detectionError detection Error correctionError correction Data compressionData compression Data encryptionData encryption

Networks EnvironmentsNetworks Environments

StandaloneStandalone

Networks EnvironmentsNetworks Environments

NetworkingNetworking

Networking BenefitsNetworking Benefits

Sharing Resources Sharing Resources InformationInformation HardwareHardware SoftwareSoftware

Fault ToleranceFault Tolerance Protecting InformationProtecting Information E-mailE-mail

Network Primary TypesNetwork Primary Types

Local Area Networks (LANs)Local Area Networks (LANs)

Wide Area Networks (WANs)Wide Area Networks (WANs)

LANLAN

local area network (LAN) is a collection of local area network (LAN) is a collection of computers located in a relatively small area and computers located in a relatively small area and connected by a common medium.connected by a common medium.

The pattern in which computers in a LAN are The pattern in which computers in a LAN are connected is called the topology.connected is called the topology.

LAN topologies include bus, star, and ring.LAN topologies include bus, star, and ring. The defining protocols for a LAN are the data-The defining protocols for a LAN are the data-

link layer protocols.link layer protocols.

Wide Area NetworkWide Area NetworkA WAN uses an external network A WAN uses an external network

provider to connect LANsprovider to connect LANs..

Example of WAN networkExample of WAN network

EX. Of WAN Frame RelayEX. Of WAN Frame Relay

A packet-switching protocol for connecting A packet-switching protocol for connecting devices on a Wide Area Network (WAN)devices on a Wide Area Network (WAN)

Frame Relay networks support data Frame Relay networks support data transfer rates at T-1 (1.544 Mbps) and T-3 transfer rates at T-1 (1.544 Mbps) and T-3 (45 Mbps) speeds(45 Mbps) speeds

Most telephone companies now provide Most telephone companies now provide Frame Relay service for customers who Frame Relay service for customers who want connections at 56 Kbps to T-1 want connections at 56 Kbps to T-1 speeds speeds

ATMATM

Short for Asynchronous Transfer ModeShort for Asynchronous Transfer Mode technology based on transferring data in cells or technology based on transferring data in cells or

packets of a fixed sizepackets of a fixed size Creates a fixed channel, or route, between two Creates a fixed channel, or route, between two

points whenever data transfer begins (Point to points whenever data transfer begins (Point to Point)Point)

Needs special ATM Device in both network, Needs special ATM Device in both network, sending & receiving sending & receiving

Rarely usedRarely used

A backbone network connects A backbone network connects segments together, forming an segments together, forming an

internet workinternet work..

Administrator Administrator ResponsibilityResponsibility

SecuritySecurity Resources AdministratingResources Administrating Applications & Data MaintainingApplications & Data Maintaining Installation & upgrading Installation & upgrading

Network RequirementsNetwork Requirements

Connections (NIC, Medium)Connections (NIC, Medium) Communication (Protocol)Communication (Protocol) Services Services

Roles of Computers in a Roles of Computers in a networknetwork

ClientsClients Request OnlyRequest Only

ServersServers Reply to Requests OnlyReply to Requests Only

PeersPeers Request & ReplyRequest & Reply

Network TypesNetwork Types

Peer to PeerPeer to Peer No Dedicated ServerNo Dedicated Server

Server BasedServer Based Dedicated Servers & ClientsDedicated Servers & Clients

CentralizedCentralized Dump TerminalDump Terminal

Peer to Peer NetworkPeer to Peer Network

WorkgroupWorkgroup No Central Logon (Local Account)No Central Logon (Local Account)

No Specific OSNo Specific OS

Advantages of Peer to PeerAdvantages of Peer to Peer

No Extra Investment for Hardware or No Extra Investment for Hardware or SoftwareSoftware

Easy SetupEasy Setup No Administrator requiredNo Administrator required Users control what to share Users control what to share No reliance on other computersNo reliance on other computers Lower Cost for small networks (10 users) Lower Cost for small networks (10 users)

Disadvantages of Peer to Disadvantages of Peer to PeerPeer

Additional Load on PCsAdditional Load on PCs Inability to handle many network Inability to handle many network

connections as serversconnections as servers Lack of Central OrganizationLack of Central Organization User should administer their own User should administer their own

computerscomputers Weak securityWeak security

Server Based NetworksServer Based Networks

Domain ModelDomain Model PDC/BDCPDC/BDC Active DirectoryActive Directory

Advantages of Server Based Advantages of Server Based NetworksNetworks

Strong SecurityStrong Security Central File StorageCentral File Storage Share Expensive EquipmentShare Expensive Equipment Dedicated Servers are optimized for their Dedicated Servers are optimized for their

jobjob Users don’t bother managing the network Users don’t bother managing the network

Advantages of Server Based Advantages of Server Based Networks [Cont.]Networks [Cont.]

Single Password allows access to all Single Password allows access to all shared resources depending on shared resources depending on permissionspermissions

Central organizationCentral organization Easy Manageable for large numbers of Easy Manageable for large numbers of

users users

Disadvantages of Server Based Disadvantages of Server Based NetworksNetworks

Expensive Dedicated HardwareExpensive Dedicated Hardware Expensive Network OSExpensive Network OS A dedicated Network Administrator A dedicated Network Administrator

Centralized NetworkCentralized Network

Using Dump-TerminalUsing Dump-Terminal

Server TypesServer Types

File & Print ServerFile & Print Server Database Servers (Application Server)Database Servers (Application Server) Mail ServersMail Servers Fax ServersFax Servers Directory Service Server (Active Directory)Directory Service Server (Active Directory)