dc lec- (network models)

DATA COMMUNICATION

Lecture-6Lecture-6

Recap of Lecture 5

• Protocols• Elements of Protocols• Standards• De-Jure• De-Facto

• Standard organizations• Internet Standards

Overview of Lecture 6

• Roles of Computer in Network• Peer• Client• Server

• Network Models• Peer to Peer (Workgroup)• Server Based (Domain Environment)

Role of Computers in Network

• There are three roles of computer in a Local Area Network

• Clients• Peers• Servers.

Role of Computers in Network (cont.)

• Clients

• A computer is called a “client” in a LAN if it contains following characteristics:

• It uses the network resources/services.• It must have a client operating system

installed on it, e.g. Win98/NT/2000Professional/XP/Vista.

• It always request server for any service.


• Peers

• A computer is called a “peer” in a LAN if it contains following characteristics:

• It provides and uses network resources.• It must have a peer operating system

installed on it, e.g. Win98/NT/2000Professional/XP/Vista.


• Servers

• A computer is called a “server” in a LAN if it contains following characteristics:

• It provides the network resources/services.• It must have server operating system

installed on it, e.g. Win NT 4 Server/2000 server/2003 Server/2008 server.

• It accepts the requests of clients.

NETWORK MODELS

Network Models

• Three main types of Network Models

1.Peer to Peer Network 2.Server-Based Network 3.Hybrid Network

Peer to Peer Network (Workgroup)

• No server No client• Every computer is a Peer• Peer is the computer, which both uses and provides

network resources. • No central login process• little security control

• Uses • Sharing disk space and resources such as printer and

faxes. • Operating Systems Used• Win 98/2000 Professional/XP/Vista

Peer to Peer Network (Cont.)

• WORKGROUP

• Workgroup is a group name given to a set of computers that are logically and physically connected together within a peer-to-peer network to share resources.

• Recommended number of computers is 10.


• ADVANTAGES:

• No extra investment in server hardware and software is required.

• Easy setup.• No network administrator is required.• Ability of users to control resources sharing.• No reliance on other computer for their

operation.• Lower cost for small network.


• DISADVANTAGES:

• Additional load on computers because of resources sharing.• Inability of peers to handle as many networks connection

as server.• Lack of central organization, which make data hard to find.• Weak security.• Lack of central management, which makes large peer

network hard to work with.• Extra cost on training the users in order to manage

resources.

Server-Based Network

• Defined by the presence of servers on a network that provide security and administration of the network.

• Server-Based or Client-Server networks divide processing tasks between clients and servers.

• Clients request services such as file storage and printing, and servers deliver them.

• Server computers typically are most powerful than client computer.

• Minimum limit of clients and servers is 1 and maximum limit depends on different factors.

• This network is managed with respect to domain.

Server-Based Network (Cont.)

• DOMAIN

• group name given to a set of computers that are logically and physically connected together within a server-based network.

• Domain security and logon permissions are controlled by special servers called domain controllers.

• There is one master domain controller in each domain, called Primary Domain Controller (PDC), which may be assisted by secondary domain controllers, called Backup Domain Controllers (BDC).


• ADVANTAGES:

• Strong central security.• Central file storage, which allows all users to work from the

same set of data and provides easy backup of critical data.• Ability to share expensive equipment, such as laser

printers.• Freeing of users from the tasks of managing the sharing

the resources.• Easy manageability of a large number of users.• Central organization, which keeps data from getting lost

among computers.


• DISADVANTAGES:

• Expensive dedicated hardware for servers.• Expensive network operating system software

and client licenses.• A dedicate network administrator (usually

required).

Hybrid Network

• Contains all three types of computers operating on• Servers• Clients• Peers.

• It generally has active domains and workgroups. • This means that while most shared resources are

located on servers, network users still have access to any resources being shared by peers in workgroup.

• It also means network users do not have to log on to the domain controller to access workgroups resources being shared by peers.

Hybrid Network (Cont.)

• ADVANTAGES

• Hybrid networks provide the advantages of server-based network and many of the advantages of peer-to-peer network.

Hybrid Network (Cont.)

• DISADVANTAGES

• Hybrid computing shares the disadvantages of server-based networking.

Summary

• Roles of Computer in Network• Peer• Client• Server

• Network Models• Peer to Peer (Workgroup)• Server Based (Domain Environment)

dc lec- (network models)

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