DATA COMMUNICATION slides

1. DATA
COMMUNICATION
LECTURE-4

2. RECAp Of LECTURE 3
• Physical Structureof Network
• Physical Topologies
1. Bus
2. Mesh
3. Star
4. Ring
5. Tree
6. Hybrid

3. OvERvIEw Of LECTURE 4
• Categoriesof Networks
• PAN
• LAN
• MAN
• WAN
• Interconnection of Networks: Internetworks
• Internet

4. CATEgORIEs/ TypEsCATEgORIEs/ TypEs
OfOf
NETwORksNETwORks

5. CATEgORIEs Of NETwORksCATEgORIEs Of NETwORks
• Computer networkscan becharacterized by their;
1. Size
2. purpose.

6. CATEgORIEs Of NETwORksCATEgORIEs Of NETwORks
(by sIzE)(by sIzE)
• Thesizeof anetwork can beexpressed by thegeographic areathey occupy
and thenumber of computersthat arepart of thenetwork.
• Networkscan cover anything from ahandful of deviceswithin asingle
room to millionsof devicesspread acrosstheentireglobe.
• Someof thedifferent networksbased on sizeare:
1. Personal areanetwork (PAN)
2. Local areanetwork (LAN)
3. Metropolitan areanetwork (MAN)
4. Wideareanetwork (WAN)

7. CATEgORIEs Of NETwORksCATEgORIEs Of NETwORks
(by pURpOsE)(by pURpOsE)
• In termsof purpose, many networkscan beconsidered general purpose,
which meansthey areused for everything from sending filesto aprinter to
accessing theInternet.
• Sometypesof networks, however, serveavery particular purpose.
• Someof thedifferent networksbased on their main purposeare:
1. Storageareanetwork, or SAN
2. Enterpriseprivatenetwork, or EPN
3. Virtual privatenetwork, or VPN

8. pERsONAL AREA NETwORkpERsONAL AREA NETwORk
• Network organized around an individual person within a single building (small
officeor residence).
• A typical PAN would includeoneor more
– computers,
– telephones,
– peripheral devices,
– video gameconsoles
– and other personal entertainment devices.
• If multiple individuals use the same network within a residence, the network is
sometimesreferred to asahomeareanetwork, or HAN.

9. Personal area network (cont..)Personal area network (cont..)
• In a very typical setup, a residence will have a single wired Internet connection
connected to amodem.
• This modem then provides both wired and wireless connections for multiple
devices.
• The network is typically managed from a single computer but can be accessed
from any device.
• Thistypeof network providesgreat flexibility.
• For example, it allowsyou to:
• Send a document to the printer in the office upstairs while you are sitting on the
couch with your laptop.
• Upload thephoto from your cell phoneto your desktop computer.
• Watch moviesfrom an onlinestreaming serviceto your TV.
• If this sounds familiar to you, you likely have a PAN in your house without
having called it by itsname.

10. local area networkslocal area networks
“A local areanetwork (LAN) isadata
communication system that allowsanumber
of independent devicesto communicate
directly with each other in alimited
geographic area.”

11. local area networks (cont..)local area networks (cont..)

12. local area networks (cont..)local area networks (cont..)
• Privately owned and links the devices within a small geographical
area.
• LAN isbasically established in a
• singleoffice,
• building,
• campus,
• or acity.
• Depending on the needs of an organization and the type of
technology used, a LAN can as simple on two PCs and printer or it
can extend throughout a company and include voice, sound and
video peripherals.
• Currently, LAN sizeislimited to afew kilometers.

13. local area networks (cont..)local area networks (cont..)
• ShareResourcesbetween PC or Workstation.
• Resourcesto beshared are
• Hardware
• Printer, Scanner, CD-Rom
• Software
• an application program
• or data.
• LANsaredistinguished from other typesof network by
• Geographical Area(Size)
• transmission media
• topology.

14. local area networks (cont..)local area networks (cont..)
• In general, agiven LAN will useonly onetypeof transmission
medium.
• Themost common LAN topologiesare
• Bus,
• Star
• Ring.
• Traditionally, LANshavedataratesin the
• 4Mbps
• 16Mbps
• 100Mbps to 1000Mbps with gigabits systems in
development.

15. 15
lan access Methodslan access Methods
• Broadcasting
• In a broadcast LAN, transmitted information will be
received by all stations simultaneously. The medium
access schemes are random access such as CSMA/CD
which may cause contention, and controlled access such as
token-passing, in which no contention will occur.
• Switching
• In aswitched architecture, aswitch forward datapacketsto
their destinations that may be a single user station or
another LAN segment.

16. 16
• Ethernet
• Fast Ethernet,
• Gigabit Ethernet
• 10G Ethernet
• Fiber Channel
• Hipper LAN
• Token ring
• ATM LAN
• FDDI (Fiber Distributed DataInterface)
• WirelessLAN
• ……..
• There are also some other technologies such as 100VG,
token bus, ARCnet, but thosearealmost obsolete.
Various local area networksVarious local area networks

17. Metropolitan area networksMetropolitan area networks

18. Metropolitan area networksMetropolitan area networks
(Mans)(Mans)
• A MAN isdesigned to extend over an entirecity or state.
• It may be a single network such as a cable television network,
or it may be a means of connecting a number of LANs into a
large network so that resources may be shared LAN-to-LAN
aswell asdevice-to-device.
• For example, a company can use a MAN to connect the
LANsin all of itsofficesthroughout acity.
• A MAN may be wholly owned and operated by a private
company, or it may beaserviceprovided by apublic company
such as local telephone company. A MAN is larger than LAN
but smaller than WAN in size.

19. wide area networkswide area networks
• Networking implemented on far away or long geographical
distances.
• For Example, networking implemented between two
continentsor countries.
• WAN is always based on connection between different LANs
and MANs.
• For Example, network between campuses of a university in
different statesof acountry.

20. wide area networkswide area networks

21. wide area networkswide area networks
“WAN provideslargedistancetransmission of
data, voice, imageand video information over
largegeographical areasthat may comprisea
country, acontinent or even thewholeworld.”

22. wide area networks
• TYPES OFWAN
• EnterpriseWAN
• A WAN that is wholly owned and is used by a single
company isknown as“EnterpriseWAN”.
• In other words network between two or more cities,
states, or countriesfor aspecific person or company,
• e.g. Network of Habib Bank Limited in Pakistan, and
network of NADRA throughout Pakistan.
• Global WAN
• A WAN that is accessible throughout the world for
anybody isknown asGlobal WAN,
• e.g. Internet and PSTN all over theworld.

23. wide area networkswide area networks
• A WAN can beas complex as thebackbones that connect theInternet or as
simpleasadial-up linethat connectsahomecomputer to theInternet.
• Wenormally refer to the
• first asaswitched WAN
• and to thesecond asapoint-to-point WAN.
• The switched WAN connects the end systems, which usually comprise a
router (internetworking connecting device) that connects to another LAN
or WAN. Examplesare:
• X.25
• FrameRelay.
• AsynchronousTransfer Mode(ATM) network
• wirelessWAN.
• Point-to-point WAN is normally a line leased from a telephone or cable
TV provider that connects a home computer or a small LAN to an Internet
service provider (ISP). This type of WAN is often used to provide Internet
access.

24. wans:wans:
a switCHed wan and a point-to-point wana switCHed wan and a point-to-point wan

25. Internetworks
• When two or more networks are connected, they become an internetwork, or
internet.
• As an example, assume that an organization has two offices, one on the east
coast and theother on thewest coast. Theestablished officeon thewest coast
has a bus topology LAN; the newly opened office on the east coast has a star
topology LAN.
• The president of the company lives somewhere in the middle and needs to
havecontrol over thecompany from hishouse.
• To create a backbone WAN for connecting these three entities (two LANs
and the president's computer), a switched WAN (operated by a service
provider such asatelecom company) hasbeen leased.
• To connect the LANs to this switched WAN, however, three point-to-point
WANsarerequired.
• These point-to-point WANs can be a high-speed DSL line offered by a
telephonecompany or acablemodern lineoffered by acableTV provider.

26. A HeteroGeneoUs network MADe
oF FoUr wAns AnD two LAns

27. Internetworks

28. sUMMAry
• Categoriesof Networks
• PAN
• LAN
• MAN
• WAN
• Interconnection of Networks: Internetworks
• Internet

29. ASSIGNMENT # 1
“Brief Introduction and History of
INTERNET”

30. sUGGesteD reADInG
• Section
 1.2,
 1.3,
• “DataCommunicationsand Networking” 4th Edition by Behrouz
A. Forouzan
• Sections
 1.3,
• “Dataand Computer Communication” 6th Edition by William
Stallings