001-006 Flashcards
is the exchange of data between two devices via a transmission medium
Data Communications
Four Fundamental Characteristics of Data Communications
- Delivery
- Accuracy
- Timeliness
- Jitter
Data Representations
- Text
- ASCII
- Extended ASCII
- UNICODE
- ISO
- Numbers
- Images
- Audio
- Video
Direction of Data Flow
- Simplex - one way
- Half Duplex - one at a time
- Full Duplex - both all the time
Set of devices connected by communication links
Network
When task is divided among computers
Distributed processing
Network Criterias
- Performance
- Reliability
- Security
Types of Connection
- Point-to-Point
- Multipoint
Physical Topologies
- Mesh
- Star
- Bus
- Ring
Every device has a dedicated point to point link to every other device
Mesh topology
Every device has a dedicated point to point link only to a central controller
Star topology
- is multipoint.
- One long cable acts as a backbone to link all the devices in a network
Bus topology
each device has a dedicated point-to-point connection with only the two devices on either side of it.
Ring topology
Categories of Network
LAN
MAN
WAN
Early: 4-16 Mbps
Today: 100-1000 Mbps
LAN
- Group of connected communicating devices
- 2 or more network that can communicate with each other
Internet
Set of rules that governs data comms
Protocols
It is the structure or format of the data
Syntax
It is the meaning of each section of bits
Semantics
It is when data should be sent and how fast it should be sent
Timing
Data Communication Standards
de facto
de jure
Standards that have not been approved but adopted as one
de facto
Officially recognized standards
de jure
Standards Organizations
ISO
ITU-T
ANSI
IEEE
EIA
OSI MODEL LAYERS
APSTNDP
It is the adding of headers/data packets
Encapsulation
removing of headers/data packets
Decapsulation
Provides interface to the network
Application layer
Converts codes & reformats data
Presentation layer
Layer concerned w/ syntax and semantics of data transmitted
Presentation layer
Coordinates interaction between end-to-end application process
Session layer
handles reliable delivery of messages
Transport layer
Routed Protocols
IP
AppleTalk
IPX
Routing Protocols
Distance Vector
Link State
Hybrid
Types of Distance Vector Routing protocols
RIP
IGRP
Types of Link State Routing protocols
OSPF
IS-IS