Network Topologies and Communication Methods: Key Concepts
What are LANs?
A Local Area Network (LAN) is a communication system that connects computers at high speed within a limited area, usually within the same building. A LAN consists of network hardware and software, providing the ability to share resources, including software, information, hard drives, directories, and printers.
What is a MAN?
A Metropolitan Area Network (MAN) is used to interconnect LANs. They are not geographically limited in size and often need to interface with special hardware, telephone lines, and modems.
What is a WAN?
A Wide Area Network (WAN) is used to connect several MANs. WANs often require special hardware. WAN links can also include satellite, fiber optics, infrared devices, and lasers. The Internet is a computer network connected to form a WAN.
What is Bus Topology?
Bus Topology logically extends from a central system. When a signal traverses the bus (usually a coaxial cable), each connection hears the signal that carries a destination address. It is easy to install, any computer can be the server, terminators are placed at the ends, and it uses cable terminators and T-connectors.
What is Star Topology?
In Star Topology, each computer is connected to a centrally located hub. The hub is a hardware device with multiple ports, allowing network cables to be connected.
What is Ring Topology?
In Ring Topology, each computer is connected in a ring. Ring topologies are almost always logical, with the physical topology being a star.
What is a Protocol?
A Protocol is a set of rules that define how communications should be structured in networks, including format, sequence, timing, revision, and error correction.
What is a Standard?
A Standard is an adopted network specification that includes guidelines and rules referring to the type of components to be used, how to connect them, and the communication protocols to be employed.
What is Network Topology?
Network Topology is the physical form of interconnection between network devices.
What is the Physical Topology of a Network?
The Physical Topology of a network is the current physical layout of the network, showing how the nodes are connected to each other.
What is the Logical Topology of a Network?
The Logical Topology of a network is the method used to communicate with other nodes, representing the route taken by network data between different network nodes.
What are the Characteristics of Coaxial Cable?
Coaxial Cable supports distances of 200 to 500 meters. It has a conductor, insulation, a shield, and a protective cover. The conductor is made of copper and may be one or more threads.
What are the Characteristics of Twisted Pair Cable?
Twisted Pair Cable is mainly used for telephone lines, also known as 10BASE-T. There are two types: Shielded Twisted Pair (STP) and Unshielded Twisted Pair (UTP). It should not be installed in fragile walls. It is the oldest type and is very secure.
What is a Waveguide?
A Waveguide is a metal tube where waves propagate, allowing electromagnetic waves to pass while avoiding interference. Examples include satellite dishes. It runs on gas or a vacuum tube for better communication and is used in TV signals.
What are the Characteristics of Fiber Optics?
Fiber Optics has a bandwidth of 50 MHz. It uses pulses of light, is thinner than a hair, and achieves maximum distances of 200 meters for local networks from node to node. It has a bandwidth of 200 Mbits per second.
What is Bandwidth?
Bandwidth is the space in the center frequency of the electromagnetic spectrum used by a transmitter. Its transmission speed is measured in bits per second.
What is Simplex Transmission Mode?
In Simplex Transmission Mode, data is transmitted in one direction, and the receiver is unable to transmit.
What is Half-Duplex Transmission Mode?
In Half-Duplex Transmission Mode, communication occurs in turns, in one direction or another. Each participant on the same link acts as a transmitter/receiver in turn.
What is Full-Duplex Transmission Mode?
In Full-Duplex Transmission Mode, data is transmitted in both directions simultaneously.
What is a Concentrator and its Characteristics?
A Concentrator is a device responsible for distributing the signal. It is divided into passive and active types. Passive concentrators only distribute the signal, while active ones amplify and divide it.
Why are the Threads in a Twisted Pair Cable Braided?
The threads in a twisted pair cable are braided to reduce electromagnetic interference on nearby pairs.
What is Non-Persistent CSMA?
Non-Persistent CSMA (Carrier Sense Multiple Access) involves detecting if the medium is occupied before sending the first data packet. If busy, it waits a random time to recheck and repeats this process until the medium is unoccupied. Upon finding it free, it sends the information packet.
How Does Token Ring Passing Work?
Token Ring Passing operates by generating a bit pattern called a token that circulates unidirectionally through all nodes in a ring network. When a node wants to send a packet, it waits for the token, then changes the last bit to indicate it is busy. The token carries the information, and upon returning to the source node, the token is freed and can be occupied by another node.
How Does Token Bus Passing Work?
Token Bus Passing uses the same technique as the ring, but there must be a logical ring formed by a sequence of addresses.
What is a Repeater?
A Repeater is a device that amplifies the signal. It receives and relays the signal, regenerating it without making any changes to the organization and structure of the information.