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Chapter 3
Communication
Technology
Computer Network
… is a telecommunications network that allows computers to exchange data. In computer networks, networked computing devices pass data to each other along data connections. The connections (network links) between nodes are established using either cable media or wireless media. The best-known computer network is the Internet.
Network Element
1.Sender – devices or sources send data/information
2.Data - message which was sent from sender to receiver
3.Receiver – destination of data/information
4.Media – the way used for passing the data/information
5.Protocol - the principal communications protocol in the Internet protocol suite for relaying datagrams across network boundaries.
Network element
Devices for Network
Computer Network Interface Card (NIC)
Physical Media – Twist pair , Coaxial , Fiber optic, Wireless
Protocol – TCP/IP Network Operating System (NOS)
Benefits of Network
Sharing resource Reduced cost Comfortable Safety for system
Type of Data
Communication
1.Unicast
… communication where a piece of information is sent from one point to another point. In this case there is just one sender, and one receiver. Or called One-to-One
2. Broadcast … communication where a piece of information is sent from one point to all other points. In this case there is just one sender, but the information is sent to all connected receivers. Or called One-to-All
3. Multicast … communication where a piece of information is sent from one or more points to a set of other points. In this case there is may be one or more senders, and the information is distributed to a set of receivers.
Communication
Direction
1.Simplex2.Half-Duplex3.Full-Duplex
1.Simplexcommunication that occurs
in one direction only. An example of a simplex device is a television, radio, satellite etc.
Communication
Direction
2. Half-Duplex the communication is one direction at a time. An example of a half-duplex device is a walkie-talkie two-way radio that has a "push-to-talk" button
Communication
Direction
3. Full-Duplexboth parties can
communicate to the other simultaneously. An example of a full-duplex device is a telephone
Communication
Direction
Type of Network
1.by flow of data2.by function of computer3.by size of service
Centralized Network
flow of data
Distributed Network
flow of data
Peer to Peer OR Workgroup
Client Server
Function of Comp.
LAN , MAN , WAN
Size of Network
… is a network confined to one building or site. Often a LAN is a private network belonging to an organization or business.
… is a network that extends over a large area. A WAN is often created by joining several LANs together, such as when a business that has offices in different countries links the office LANs together.
๐ What’s Ethernet ??? … is a family of computer networking technologies for LANs. The original 10 megabits per second used twisted pair. Later the coaxial cables were replaced with twisted pair, data rates were periodically increased from the original 10 megabits per second to 100 gigabits per second.
1.LANs are most likely based on Ethernet technology, Token Ring, FDDI
Networking Standard
Wire
1.2 Token-Ring … is a protocol which
resides at the data link layer (DLL) of the OSI model. It used a special three-byte frame called a token that travels around the ring. Token-possession grants the possessor permission to transmit on the medium. Token ring frames travel completely around the loop. It was eventually standardized with protocol IEEE 802.5
1.3 FDDI (Fiber Distributed Data Interface)
… is a standard for data transmission in a local area network. It uses optical fiber as its standard underlying physical medium. It’s protocol was derived from the IEEE 802.4 token bus
Wireless
… is any type of computer network that uses wireless data connections for connecting network nodes, or as a connection between various equipment locations.
Type of Wireless
1.WPAN (wireless personal area network)
2.WLAN (wireless local area network)
3.WMAN (wireless metropolitan area network)
4.WWAN (wireless wide area network)
1.WPAN… is a computer network
used for wireless data transmission among devices such as computers, telephones and personal digital assistants such asIR (Infra-Red) , Bluetooth , NFC
2. WLAN is a LAN that uses radio
signals (WiFi) to connect computers instead of cables.
3. WMAN … is optimized for a larger geographical area than a LAN, ranging from several blocks of buildings to entire cities. It has been commercialized under the name "WiMAX"
4. WWAN… is a form of wireless network, requires differences in technology. Wireless networks of all sizes deliver data in the form of telephone calls, web pages, and streaming video.
Networking Standard
Wireless
1.IEEE802.112.IEEE802.11a3.IEEE802.11b4.IEEE802.11g5.IEEE802.11n
… is a set of media access control (MAC) and physical layer (PHY) specifications for implementing wireless local area network (WLAN). It specified two net bit rates of 1 or 2 megabits per second (Mbit/s)
1. IEEE802.11
… allow transmission and reception of data at rates of 1.5 to 54Mbit/s. It operates in the 5 GHz band, so that its not allow using in Thailand.
2. IEEE802.11a
The 802.11b standard has a maximum raw data rate of 11 Mbit/s. Devices operating in the 2.4 GHz range include microwave ovens, Bluetooth devices, baby monitors, cordless telephones and some amateur radio equipment.
3. IEEE802.11b
Like 802.11b, 802.11g devices suffer interference from other products operating in the 2.4 GHz band, for example wireless keyboards.
4. IEEE802.11g
802.11n is an amendment which improves upon the previous 802.11 standards by adding multiple-input multiple-output antennas (MIMO). It operates at a maximum net data rate from 54 Mbit/s to 600 Mbit/s.
5. IEEE802.11n
Effective Criteria
1. Competency2. Reliability3. Security
1. Competency)1.1 time for data transfers
1.2 amount of user in network
1.3 type of media1.4 Devices
2. Reliability2.1 The frequency of failure in data transmission2.2 The duration of the recovery or system recovery in case of failure.2.3 Prevention to the system failure.
3. Security3.1 Right of access to information 3.2 Threat Protection – Virus computer
Benefit of Network
1. Communication1.1 E-board1.2 E-mail1.3 E-conference1.4 Online conversation – Cha
etc.
2. Data searching… to search for data or information on the WWW, which result of searching be Text, Image, Sound, or Multimedia.
3. Business3.1 Electronic data exchange3.2 Electronic funds transfer3.3 Electronic commerce
4. Education E-learning | E-media | distance learning | blended learning | M-learning
5. Medical Telemedicine | Video telephony | Telenursing | Telepharmacy | Telesurgery | Health information technology
Telemedicine
SDU : IT Services
1. SDU Web Hosting Service
2. Identity Manager | IDM
SDU : IT Services
3. SDU Kiosk
SDU : IT Services
4. SDU mailhttps://
sdumail.dusit.ac.th/
SDU : IT Services
5. SDU WIFI
๐ Dusit๐ Dusit Guest๐ Dusit Secure
SDU : IT Services
SDU WIFI
7. WebVPN
SDU : IT Services
http://webvpn.dusit.a
c.th
WebVPN
QUESTION ?