Introduction - Networks

• LAN (Local Area Network)– Does not Type 1 Telecommunication carrier – Cover limited area (maximum 20km)

– Factories, Hospitals, Schools

• WAN (Wide Area Networks)– Uses Type 1 Telecommunication carrier – Cover wider area with high speed digital lines

MELJUN CORTESMELJUN CORTES

Network

WAN

Network: Classified by place which used

Company A (HQ)

Company A (BR)

Company A (BR)

LAN

LAN

Local Area Network

LAN: Network located limited place such as inside building or floor.

3F 2F

1F

Wide Area Network

LAN

LAN

WAN

Common Carrier owned the Communication line

WAN: Connects between two different places via Common Carrier’s line

3.1.1 Features of a LAN

• Benefits of LAN– Share resources such as database – Centralized information

– Highly reliable, high quality of communication within limited area

– No line charges of use of line – Few Transmission Errors – Allow open distributed systems – User manage the entire network

Classification of LAN

Network Topology Star Type

Bus Type

Ring Type

Mid (1 to 2Mbps)

High (100 Mps)

Twisted Pair

Coaxial

Optic-fiber

Infra-red, Radio

Baseband

Broadband

CSMA/CD

Token Passing

CSMA/CA

Transmission Speed

Transmission Media

Transmission Method

Network Topology

LAN Classification by Connection type and Usage

Backbone LAN

Access LAN

Access LANAccess LAN

Access LAN: Connects personal computers and serversBackbone LAN: High speed and high reliability which bundles Access LAN

Network Topology

3.1.2 Topology of LAN

Terminal 6

Terminal 5

Terminal 4 Terminal 3

Terminal 2

Terminal 1

(1)

• Features of Star Networks– Easy to add and move terminals connected

to network– Restriction on no. of connectible terminals

and distance from concentrator – One terminal fail would not affect the entire

network– If concentrator fails the entire network will

go down

3.1.2 Topology of LAN

3.1.2 Topology of LAN

• Features of bus network are:– Simplest wiring, but if terminals is moved

bus wiring must be redone– Restriction on length of bus and no. of

terminals – Allows multi-destination transmission– Collision of data may occur – Unnecessary data eliminated by

terminators

3.1.2 Topology of LAN

3.1.2 Topology of LAN

Terminal 1

Terminal 2

Terminal 3 Terminal 4

Terminal 5

Terminal 6

• Features of ring networks are:– Data passes around the ring in one direction – If destination address matches terminal then data

is seized, otherwise data is passed on

– Data transmission control can stop data collisions

– Establishment of bypass route is necessary

3.1.2 Topology of LAN

3.1.3 LAN Connection Architecture - continue

• (1) Peer-to-peer– Requires no dedicated server machine– Each machine considered equal

– Personal terminals manage all tasks

– Simple and cheap to construct – Not suitable for heavy data loads– Not suitable for advanced computations