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
4.1.2 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
4.1.3 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
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
4.2.2 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
4.2.3 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 (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