Lan man wan

3. Understand the rationale for the existence of networks.Understand the rationale for the existence of networks.
Distinguish between the three types of networks:Distinguish between the three types of networks: LANsLANs,, MANsMANs,,
andand WANsWANs..
After reading this chapter, the reader shouldAfter reading this chapter, the reader should
be able to:be able to:
OOBJECTIVESBJECTIVES
List different connecting devices and the OSI layers in whichList different connecting devices and the OSI layers in which
each device operates.each device operates.
UnderstandUnderstand client-server modelsclient-server models..
Understand theUnderstand the OSI modelOSI model andand TCP/IPTCP/IP..

4. NETWORKS,NETWORKS,
LARGE AND SMALLLARGE AND SMALL

5. NetworkNetwork
 Computer networkComputer network ––
A combination of computersA combination of computers
connected throughconnected through transmissiontransmission
mediamedia..
• LAN (Local Area Network)LAN (Local Area Network)
• MAN (Metropolitan Area Network)MAN (Metropolitan Area Network)
• WAN (Wide Area Network)WAN (Wide Area Network)
 InternetworkInternetwork – (e.g. Internet)– (e.g. Internet)
Networks can be connected usingNetworks can be connected using
connecting deviceconnecting device..

6. Model and ProtocolModel and Protocol
 ModelModel ––
thethe specificationspecification set by aset by a standardsstandards
organizationorganization as aas a guideline forguideline for
designing networksdesigning networks..
 ProtocolProtocol ––
a set of rulesa set of rules that controls thethat controls the
interaction of different devices in ainteraction of different devices in a
network/internetwork.network/internetwork.

7. CATEGORIESCATEGORIES
OFOF
NETWORKSNETWORKS

8. Categories of networks

9. LAN (Local Area Network)LAN (Local Area Network)
 AllowAllow resource sharingresource sharing betweenbetween
computers.computers.
• ComputersComputers
• Peripheral devicesPeripheral devices
• Transmission medium (e.g. cable)Transmission medium (e.g. cable)
 3 types of topology3 types of topology
• Bus topologyBus topology
• Star topologyStar topology
• Ring topologyRing topology

10. LANs
 Hub –Hub –
• a device thata device that
facilitates connectionfacilitates connection
• LAN acts logically like a bus.LAN acts logically like a bus.
 Star –Star –
the dominant topology today.the dominant topology today.

11. MAN

12. MAN (Metropolitan Area Network)MAN (Metropolitan Area Network)
 Uses services provided by aUses services provided by a network servicenetwork service
provider. (Tel. Company)provider. (Tel. Company)
• Individual users’ computersIndividual users’ computers
• Organizations’ LANsOrganizations’ LANs
 Many Tel. Company provide a popular MANMany Tel. Company provide a popular MAN
service calledservice called SMDSSMDS (Switched Multimegabit Data(Switched Multimegabit Data
Services)Services)
• Prior to SMDS's arrival in 1995,Prior to SMDS's arrival in 1995,
the only way to connect LANs was throughthe only way to connect LANs was through
aa dedicated private linededicated private line..

13. WAN

14. WAN (Wide Area Network)WAN (Wide Area Network)
 The connection ofThe connection of individual computersindividual computers oror
LANsLANs over a large areaover a large area (country, world).(country, world).
 User using aUser using a telephone linetelephone line to connect toto connect to
anan ISP (Internet Service Provider)ISP (Internet Service Provider) is usingis using
a WAN.a WAN.
• Negotiates feeNegotiates fee
 ISPISP
 Tel. companyTel. company

15. CONNECTINGCONNECTING
DEVICESDEVICES

16. Connecting devices

17. Repeater (L1)
 RegeneratesRegenerates the signal.the signal.
 Extends the physical lengthExtends the physical length of a network.of a network.

18. Repeaters operate at the first layer ofRepeaters operate at the first layer of
the OSI model.the OSI model.
Note:Note:

19. Bridge/SwitchBridge/Switch
 BridgeBridge
• A traffic controllerA traffic controller
• Divide aDivide a long buslong bus intointo smaller segmentssmaller segments
so that each segment isso that each segment is independentindependent trafficwise.trafficwise.
• Regenerate dataRegenerate data
 SwitchSwitch
• AA sophisticated bridgesophisticated bridge withwith multiple interfacesmultiple interfaces..
• A station that needs to send aA station that needs to send a frameframe sends itsends it
directly to the switch.directly to the switch.

20. Bridge (L1-L2)

21. Bridges operate at the first twoBridges operate at the first two
layers of the OSI model.layers of the OSI model.
Note:Note:

22. Figure 6-10
Switch

23. RouterRouter
 ConnectConnect LANsLANs,, MANsMANs, and, and WANsWANs..
 RoutesRoutes a packet based on thea packet based on the logicallogical
address (network layer)address (network layer) of theof the packetpacket..
 ConnectConnect twotwo independentindependent networksnetworks: LAN-: LAN-
WAN, LAN-MAN, WAN-WAN…WAN, LAN-MAN, WAN-WAN…
V.S.V.S.
 BridgeBridge
• filters a frame based on thefilters a frame based on the physical addressphysical address
(data-link layer)(data-link layer) of theof the frameframe..
• ConnectConnect twotwo segmentssegments of a LAN orof a LAN or twotwo LANsLANs
belonging to the same organization.belonging to the same organization.

24. Figure 6-11
Routers (L1-L3) in an internet

25. Routers operate at the first threeRouters operate at the first three
layers of the OSI model.layers of the OSI model.
Note:Note: