Module 1 - Introduction to Data Communications and Networks Flashcards
Data Communications
process of transferring digital information between two or more points.
Information
knowledge, idea, concept
Data
processed information
Computer Network
interconnected set of independent computers
Not Networks
- Master/slave computers
2. Computer with dumb terminals and printers
Benefits of Data Communication and Networking
- Speed
- Convenience
- Cost Reduction / Resource Sharing (printers, disk drives)
- Network can become communication medium: ex: www / videoconferencing
Topologies for Network Hardware Devices
- Ring
- Star
- Tree
- Fully Connected
- Bus
- Irregular
Enumerate Network Classifications
- LAN - Local Area Network
- MAN - Metropolitan Area Network
- WAN - Wide Area Network
internetwork / internet
WAN that connects several LANs
Types of transmission technology
- broadcast / multi-access networks - also called MABN - multiple access / multi-access broadcast network
- point-to-point networks
Modes of Point-to-Point Links
- Simplex - one direction only
- Half-Duplex - both directions but not simultaneously
- Full-Duplex - both directions simultaneously
Peers
Layers of equal level
Interface
A boundary between layers that tells the layer above the interface how to access the layer below.
Defines which primitives (operations) and services the lower layer offers to the upper layer.
Primitive
an operation
Protocol
rules followed by peers
Entity
An active element in a layer, can be software or hardware
Layer N
Service Provider
Layer N+1
Service User
Well-Defined Interface
- Performs well-understood functions
- Minimizes the amount of information passed between layers, thereby avoiding redundancy and long interlayer transaction
- Makes it simpler to replace the implementation, as long as the replacement offers the exact same services to the upper layer
MABN
multi-access broadcast network
ISO
International Organization for Standardization
OSI
Open Systems Interconnection
OSI Seven Layers
- Application Layer
- Presentation Layer
- Session Layer
- Transport Layer
- Network Layer
- Data Link Layer
- Physical Layer
Physical Layer, 4 Important characteristics
- Mechanical
- Electrical
- Functional
- Procedural
