Basics of Data Communication
COMPUTER NETWORKS - CS65
Department of EEE,MEPCO
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Data communications (Datacom) is the engineering Datacom) discipline concerned with the communication between devices. A network is a set of devices (often referred to as nodes) nodes) connected by communication links. links. A computer network is any set of computers or devices connected to each other via some form of transmission medium with the ability to exchange data. Here information is presented in a form which is agreed upon by the parties creating and using the data. A computer network must be able to meet a certain number of criteria. The most important of these are criteria. Performance : measured in “throughput” & “delay” Reliability : measured by the frequency of failure or time taken by the link to recover from failure. failure. Security : protecting from unauthorized access or damage
January 25, 2011
BASICS OF DATA COMMUNICATION
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- Direct – Simple and directly connected COMPONENTS Five components of communication 1. Message 2. Sender 3. Receiver 4. Transmission Medium 5. Rules to be followed for communication(Protocol)
DIRECT NETWORK
- Indirect – Two entities must depend on the functioning of other entities to exchange data. All the entities may be within a group or two or more group.
January 25, 2011
January 25, 2011
Prepared by Dr.S.Muralidharan
1
COMPUTER NETWORKS - CS65
Department of EEE,MEPCO
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PHYSICAL TOPOLOGY : Refers to the way in which a network is laid out physically. Two or more devices connect to a link; two or more links form a topology. A fully connected mesh topology (five devices)
January 25, 2011
January 25, 2011
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Advantages :
• • • •
A star topology connecting four stations
Dedicated connection between a pair of computers guarantees the congestion free data transfer Failure of one link does not affect the data transfer Each message travels through dedicated path.
Department of EEE,MEPCO
Page 2
Data communications (Datacom) is the engineering Datacom) discipline concerned with the communication between devices. A network is a set of devices (often referred to as nodes) nodes) connected by communication links. links. A computer network is any set of computers or devices connected to each other via some form of transmission medium with the ability to exchange data. Here information is presented in a form which is agreed upon by the parties creating and using the data. A computer network must be able to meet a certain number of criteria. The most important of these are criteria. Performance : measured in “throughput” & “delay” Reliability : measured by the frequency of failure or time taken by the link to recover from failure. failure. Security : protecting from unauthorized access or damage
January 25, 2011
BASICS OF DATA COMMUNICATION
Page 3
Page 4
- Direct – Simple and directly connected COMPONENTS Five components of communication 1. Message 2. Sender 3. Receiver 4. Transmission Medium 5. Rules to be followed for communication(Protocol)
DIRECT NETWORK
- Indirect – Two entities must depend on the functioning of other entities to exchange data. All the entities may be within a group or two or more group.
January 25, 2011
January 25, 2011
Prepared by Dr.S.Muralidharan
1
COMPUTER NETWORKS - CS65
Department of EEE,MEPCO
Page 5
Page 6
PHYSICAL TOPOLOGY : Refers to the way in which a network is laid out physically. Two or more devices connect to a link; two or more links form a topology. A fully connected mesh topology (five devices)
January 25, 2011
January 25, 2011
Page 7
Page 8
Advantages :
• • • •
A star topology connecting four stations
Dedicated connection between a pair of computers guarantees the congestion free data transfer Failure of one link does not affect the data transfer Each message travels through dedicated path.