Networking Flashcards
Network Categories
PAN
LAN
MAN
WAN - Combination of two or more MAN and LAN.s
Network Topologies
Bus
Ring
Star
Mesh
Hybrid
Best Network topology
Hybrid
Reasons: Fault tolerant
Cons: Expensive to set up
Types of data Transmission mediums
- Analog Signal: using infinite levels of intensity over a period of time. Hence, resulting in a continuous waveform
- Digital Signal: using binary digits (which has a finite number of possibilities
Analogue Transmission Cons
- Susceptible to electromagnetic interference
- Susceptible to distortion
Components of data transmission
- Sender
- Receiver
- Data
- Channel (medium)
- Protocol
Transmission modes
- Simplex
- Half duplex
- Full duplex
Methods of transmission
i. Serial (Synchronous & Asynchronous)
ii. Parallel
Multiplexing
Process of combining multiple signals or data streams into a single signal or transmission medium
Types of multiplexing
- Time Division Multiplexing (TDM)
- Frequency Division Multiplexing (FDM)
- Wave Division Multiplexing
- Statistical Time Division Multiplexing ( STDM)
Circuit Switching and Packet Switching
Circuit switching is an older method that was used in traditional telephone networks. In circuit switching, a dedicated physical circuit is established between the sender and the receiver for the duration of the communication session. This circuit is reserved exclusively for the use of that communication session, even if there is no data being transmitted. This means that the resources of the network are tied up for the duration of the session, even if there are periods of inactivity. Circuit switching is ideal for applications that require a continuous and dedicated connection, such as voice calls.
Packet switching, on the other hand, is a newer method of transmitting data that is used in modern computer networks, including the Internet. In packet switching, data is divided into small packets that are sent individually from the source to the destination. Each packet is sent independently and can take a different route to the destination. This means that the network resources are shared among many users and applications, and packets from different sources can be interleaved on the same transmission medium. Packet switching is ideal for applications that require bursty data transmission, such as file transfers and web browsing.
In summary, circuit switching is a method of establishing a dedicated connection between two points, while packet switching is a method of transmitting data in small, independent packets over a shared network.
What is distortion
Distortion in network media occurs when the original signal is altered or degraded during transmission over a network medium. Distortion can occur due to several factors, including attenuation, noise, interference, and delay.
Attenuation
Attenuation is the loss of signal strength as it travels over a network medium. The signal strength reduces as the distance between the transmitting and receiving devices increases. Attenuation is more significant in wired networks, such as copper or fiber optic cables, than in wireless networks.
Types of Network Media
Wired and Unwired Networks
OR
Bounded Media:
1. Twisted Pair (Shielded and Unshielded)
2. Coaxial
3. Fiber Optic
Unbounded Media
Sources of Distortion (4)
- Attenuation: Decrease in Amplitude of signals as they travel along transmission Media.
- Limited Bandwidth:
- Noise and Crosstalk
- Delay Distortion
Types of Bounded Media
- Coax
- Twisted Pair
- Fiber-Optics
Types of Coax
- Thinnet (10Base2)
- Thicknet (10Base5)
Define the term Computer Networks
Computer Networks refer to a collection of interconnected computers and other devices that communicate and share resources with one another. They are designed to enable the exchange of data, information, and resources among connected devices, allowing users to access and share data across different locations.
What is Data Encapsulation?
When data is transmitted over a network, it goes through multiple layers of the OSI (Open Systems Interconnection) or TCP/IP model. Each layer adds its own header and sometimes a trailer to the original data, forming a new unit known as a “protocol data unit” (PDU) specific to that layer.
The encapsulated data moves down through the layers during the transmission from the sender to the receiver. At each layer, the PDU is processed and the corresponding layer’s header and trailer are added or removed
OSI Model
- Physical
- Data-Link
- Network
- Transportation
- Segment
- Presentation
- Application
Sources of distortion
- Thermal Noise
- Delay Distortion
- Limited Bandwidth
- Noise
- Attenuation
Bounded Vs Unbounded Media
1. Bounded media use physical cables or conductors to transfer data from one point to the other eg.
Twisted Pair, Coax, Fiber-optics
2. Unbounded Media: Transmission of data through air or space without using any physical medium.
eg, Bluetooth, Wi-fi, infrared
Coax cable Application
- Television Distribution
- Long distance Telephone connection
- LAN
- Short run computer systems link
Define Data Communication
Data Communication is the transmission of Analog or Digital data over a communication medium or between two or more devices
Define Network Gateway
A Hardware or Software that connects two or more networks together.
A gateway can perform the following:
1. Protocol conversion,
2. data routing
3. Data routing
4. packets
filtering
5. Security and access control
