Transcript

Chapter 4 Types of NetworkChapter 4 Types of Network

4.14.1 LAN and WAN

4.24.2 Network TopologyNetwork Topology

BusBus

StarStar

RingRing

MeshMesh

Chapter 4 Types of Network

4.1 LANs, MANs and WANs4.1 LANs, MANs and WANs

According to the geographical area covered, networks can be classified into LAN

Local Area Network

MANMetropolitan Area Network

WANWide Area Network

PANPersonal Area Network

Chapter 4 Types of Network

4.1.1 LAN

Local Area Network (LAN) formed by joining computers

in short distancese.g. within the same building or within a campus

can be found in home, offices, schools and universities, etc.

the technology used is mainly Ethernetmaximum effective length of UTP cable < 100 msometimes need fiber-optic cables

Chapter 4 Types of Network

4.1.1 LAN

Chapter 4 Types of Network

4.1.2 MAN

Metropolitan Area Network (MAN) connects two or more LANs

within a specific geographic region• e.g. town/city

Each LAN is connected to a routerby long distance communication links

• phone lines

• microwave

• fiber-optic cable

mainly privateusers are required to login to use the serviceexcept for those maintained by ISPs

Chapter 4 Types of Network

4.1.2 MAN

Chapter 4 Types of Network

4.1.3 WAN

Wide Area Network (WAN) connects two or more LANs distances measured in miles

across countriesby routers and communication links

Large companies: private WANs each branch form a LAN

• linked together to form the WAN

The Internet public WAN

• supported by ISPs all over the world

Chapter 4 Types of Network

4.1.3 WAN

Chapter 4 Types of Network

PAN

Personal Area Network (PAN) linking mobile devices to a computer

Mainly BlueTooth

Chapter 4 Types of Network

4.1.4 Users’ View

Users

cannot easily distinguish between LAN, MAN and WAN

because they look and operate in similar way

Chapter 4 Types of Network

4.2 Network Topology

Network topology the shape of the logical linking of devices on a network

Common topologies bus star ring

Chapter 4 Types of Network

4.2.1 Bus Topology (1/2)

Bus topology consists of a long cable

to link the devices on the network shared medium usually a coaxial cable

Adv: easy to install least amount of cable

Disadv: difficult to trouble-shootmain cable fails → entire network fails

Typical examples Ethernet 10Base-2, 10Base-5

Chapter 4 Types of Network

4.2.1 Bus Topology (2/2)

Chapter 4 Types of Network

4.2.2 Star Topology (1/2)

Star topology consists of a cable concentrator

hub/switch all data transfer pass through

Adv. easy to maintain flexible in adding or removing nodes failure of a node will not affect whole network

Disadv. hub fails → entire network fails largest amount of cables hub-based can be deteriorate if the network grows

Examples: Almost all Ethernet networks & Wireless LAN

• except for the old 10Base-2 and 10Base-5

Chapter 4 Types of Network

4.2.2 Star Topology (2/2)

Chapter 4 Types of Network

4.2.3 Ring Topology (1/3)

Ring topology connects devices in a closed ring Data travels in one direction

until it reaches the destination or returns to the sender

Adv. can support large number of nodes

Disadv.a node fails → entire network failsexpensive

Examples:• Token Ring -- common in mainframe systems

Chapter 4 Types of Network

4.2.3 Ring Topology (2/3)

Chapter 4 Types of Network

4.2.3 Ring Topology (3/3)

Physical Wiring of a ring network

nodes are connected to a central device called Multistation

Access Unit (MAU)

cables are physically wired in a star

Chapter 4 Types of Network

4.2.4 Comparison between Topologies

Topologies Advantages Disadvantages

Bus • Require least actual wires • Difficult to trouble-shoot because the cable connection extends to all nodes

• If the main cable is broken, the network fails.

Star • Easy to maintain• Flexible in adding or

removing nodes• If a node fails, the network

can still operate

• If the hub fails, the entire network fails

• Require more cabling• The performance of a hub-based

network would deteriorate if there are too many nodes

Ring • Can support large number of nodes (without the problem of collisions associated with a hub-based network)

• Failure in any node will cause failure of the entire network

• Expensive

Chapter 4 Types of Network

4.2.5 Mesh Topology

Mesh topology each computer connects

to all other computers most expensive redundancy – fault-

tolerant


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