Data communication

คุ�ณลั�กษณะ 3 อย่�างที่��มี�ผลัต่�อการสื่��อสื่ารข้�อมี�ลั1. Delivery

2. Accuracy

3. Timeliness

(Real time transmission)

Components

Massage

Step 1:Step 2:Step 3:………………

Step 1:Step 2:Step 3:………………

Protocol Protocol

Sender ReceiverMedium

Components1. Massage

- text - number - pictures- sound - Video

2. Sender- a computer - workstation - telephone handset - video camera

3. Receiver- a computer - workstation - telephone handset - television

4. Medium

- twisted pair wire - coaxial cable

- fiberoptic cable - laser

- radio wave or satellite microwave

5. Protocol

Components

Basic Concepts

Line configuration

Topology

Transmission mode

Categories of networks

Internetworks

1. Line configuration

Line configuration

MultipointPoint-to-point

Two categories of line configuration

Link

LinkWorkstation Workstation

WorkstationMainframe

Point-to-point

Multipoint

Link

2. Topology

Topology

StarMesh Tree Bus Ring

Mesh

ต่�วอย่�างกรณ�ที่��มี�เคุร��องคุอมีพิ�วเต่อร� 8 เคุร��องต่�องการเชื่��อมีต่�อก�นในร�ปแบบ

Mesh ให้�คุ'านวณห้า Number of link แลัะ Number of point per Device

Solution

Number of link = n(n-1)/2 = 8(8-1)/2 = 28

Number of point per Device = n-1 = 8-1=7

Star

Hub

Tree

HubHub Hub

Hub

Bus

Dropline

Dropline

Dropline

Dropline

Tap Tap Tap Tap

Cable end Cable end

Ring

Hybrid Topologies

Hub

Hub

Bus

Ring

Star

Star

3. Transmission Mode

Transmission Mode

Full-duplexSimplex Half-duplex

Simplex

€

MainframeMonitor

Direction of data

Half -duplex

Workstation

Direction of data at time 1

Direction of data at time 2Workstation

Full-duplex

Workstation

Direction of data all the time

Workstation

4. Categories of network

Local Area Network (LANs)

Metropolitan Area Network (MANs)

Wide Area Network (WANs)

Local Area Network (LAN)

Single building LAN

Local Area Network (LAN)

Backbone

Multiple building LAN

Metropolitan Area Network (MAN)

Public city networkPublic city network

Wide Area Network (WAN)

5. Internetworks

WANWAN

LANLAN

LANLAN

LANLAN

LANLAN

LANLAN

MANMAN

R

R

R

R

R

R

R R