MODULE 2 Flashcards
It is an interconnected set of autonomous computers.
Computer Network
Computer networks have emerged as a result of the convergence of two technologies of this century
Computer and Communication
The exchange of data between two nodes (e.g., computer) via some form of transmission media (e.g., cable).
Data Communication
3 types of data flow
✓ Simplex
✓ Half Duplex
✓ Full Duplex
In this case data flows in only one direction on the data communication line (medium).
Simplex
Data flows in both directions but not at the same time. If one device is sending, the other can only receive (vice versa).
Half Duplex
Data flows in both directions simultaneously. Device can send and receive at the same time.
Full Duplex
It is a set of rules that govern data communication.
Protocol
Protocol used in network communications also define:
✓ Message Encoding
✓ Message Formatting and encapsulation
✓ Message timing
✓ Message size
✓ Message delivery options
Illustration of message encoding:
Message source – Encoder (Signal) – Transmitter – Transmitter Medium – Receiver - Decoder (Signal) - Message Destination
Both sender and receiver must agree upon a format.
Message Formatting
The process in which some extra information is added to the data item to identify the sender and receiver.
Data Encapsulation
Long messages must be broken into smaller pieces to travel across a network so that the transmission medium can handle it.
Message Size
3 Types of Message Delivery Options
✓ Unicast
✓ Multicast
✓ Broadcast
2 Types of Transmission Network
✓ Broadcast Network
✓ Point-to-point Network
It has a single communication channel that is shared by all the machines on the network.
Broadcast Networks
This system generally also
allows possibility of addressing
the packet to all destinations (all nodes on the network). When
such a packet is transmitted
and received by all the
machines on the network, this mode of operation is known as ___ .
Broadcast Mode
Some Broadcast systems also supports transmission to a sub-set of machines, something
known as ___ .
Multicasting