DATA COMMUNICATION slides

1. DATA
COMMUNICATION
LeCTUre-6LeCTUre-6

2. reCAp Of LeCTUre 5
• Protocols
• Elementsof Protocols
• Standards
• De-Jure
• De-Facto
• Standard organizations
• Internet Standards

3. OvervIew Of LeCTUre
6
• Rolesof Computer in Network
• Peer
• Client
• Server
• Network Models
• Peer to Peer (Workgroup)
• Server Based (Domain Environment)

4. rOLe Of COMpUTers IN
NeTwOrk
• There are three roles of computer in a Local
AreaNetwork
• Clients
• Peers
• Servers.

5. rOLe Of COMpUTers IN
NeTwOrk (CONT.)
• Clients
• A computer is called a “client” in a LAN if it contains
following characteristics:
• It usesthenetwork resources/services.
• It must have a client operating system installed
on it, e.g.
Win98/NT/2000Professional/XP/Vista.
• It alwaysrequest server for any service.

6. rOLe Of COMpUTers IN
NeTwOrk (CONT.)
• Peers
• A computer is called a “peer” in a LAN if it contains
following characteristics:
• It providesand usesnetwork resources.
• It must have a peer operating system installed
on it, e.g.
Win98/NT/2000Professional/XP/Vista.

7. Role of ComputeRs in
netwoRk (Cont.)
• Servers
• A computer is called a “server” in a LAN if it contains
following characteristics:
• It providesthenetwork resources/services.
• It must have server operating system installed on it, e.g.
Win NT 4 Server/2000 server/2003 Server/2008 server.
• It acceptstherequestsof clients.

8. netwoRk
moDels

9. netwoRk moDels
• Threemain typesof Network Models
1.Peer to Peer Network
2.Server-Based Network
3.Hybrid Network

10. peeR to peeR netwoRk
(woRkgRoup)
• No server No client
• Every computer isaPeer
• Peer is the computer, which both uses and provides network
resources.
• No central login process
• littlesecurity control
• Uses
• Sharing disk spaceand resourcessuch asprinter and faxes.
• Operating SystemsUsed
• Win 98/2000 Professional/XP/Vista

11. 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
apeer-to-peer network to shareresources.
• Recommended number of computersis10.

12. peeR to peeR netwoRk
(Cont.)
• ADVANTAGES:
• No extra investment in server hardware and software is
required.
• Easy setup.
• No network administrator isrequired.
• Ability of usersto control resourcessharing.
• No relianceon other computer for their operation.
• Lower cost for small network.

13. Peer to Peer Network
(CoNt.)
• DISADVANTAGES:
• Additional load on computersbecauseof resourcessharing.
• Inability of peers to handle as many networks connection as
server.
• Lack of central organization, which makedatahard to find.
• Weak security.
• Lack of central management, which makes large peer
network hard to work with.
• Extracost on training theusersin order to manageresources.

14. Server-BaSed Network
• Defined by the presence of servers on a network that provide
security and administration of thenetwork.
• Server-Based or Client-Server networks divide processing
tasksbetween clientsand servers.
• Clients request services such as file storage and printing, and
serversdeliver them.
• Server computers typically are most powerful than client
computer.
• Minimum limit of clients and servers is 1 and maximum limit
dependson different factors.
• Thisnetwork ismanaged with respect to domain.

15. Server-BaSed Network
(CoNt.)
• DOMAIN
• group name given to aset of computersthat arelogically and
physically connected together within aserver-based network.
• Domain security and logon permissions are controlled by
special serverscalled domain controllers.
• There isone master domain controller in each domain, called
Primary Domain Controller (PDC), which may be assisted
by secondary domain controllers, called Backup Domain
Controllers(BDC).

16. Server-BaSed Network
(CoNt.)
• ADVANTAGES:
• Strong central security.
• Central file storage, which allows all users to work from the
sameset of dataand provideseasy backup of critical data.
• Ability to shareexpensiveequipment, such aslaser printers.
• Freeing of users from the tasks of managing the sharing the
resources.
• Easy manageability of alargenumber of users.
• Central organization, which keeps data from getting lost
among computers.

17. Server-BaSed Network
(CoNt.)
• DISADVANTAGES:
• Expensivededicated hardwarefor servers.
• Expensive network operating system software and client
licenses.
• A dedicatenetwork administrator (usually required).

18. HyBrid Network
• Containsall threetypesof computersoperating on
• Servers
• Clients
• Peers.
• It generally hasactivedomainsand workgroups.
• This means that while most shared resources are located on
servers, network users still have access to any resources being
shared by peersin workgroup.
• It also means network users do not have to log on to the domain
controller to accessworkgroupsresourcesbeing shared by peers.

19. Hybrid Network (CoNt.)
• ADVANTAGES
• Hybrid networks provide the advantages of server-based
network and many of the advantages of peer-to-peer
network.

20. Hybrid Network (CoNt.)
• DISADVANTAGES
• Hybrid computing shares the disadvantages of server-
based networking.

21. Summary
• Rolesof Computer in Network
• Peer
• Client
• Server
• Network Models
• Peer to Peer (Workgroup)
• Server Based (Domain Environment)