Networking

  What is a backbones ? backbones are large networks owned by some communication companies such as Sprint, Verizon (MCI), AT&T, and NTT.  What is peering points ? The backbone networks are connected through some complex switching systems, called peering points. At the second level, there are smaller networks, called  provider networks  . What is provider networks ? that use the services of the backbones for a fee.  The provider networks are connected to backbones and sometimes to other provider networks. What is customer networks ? The customer networks are networks at the edge of the Internet that actually use the services provided by the Internet. They pay fees to provider networks for receiving services.  Read also : What is Internet ? Internet network ? ISPs vs customer vs provider vs backbones Network Switching Definition & Types ? circuit-switched networks VS packet-switched networks ? What is Intern et Service Providers (ISPs) ? Backbones and provider networks are also c

 NETWORK TYPES

  Bus Topology What is Bus Topology ?   is multipoint.  One long cable acts as a backbone to link all the devices in a network . Nodes are connected to the bus cable by drop lines and taps. A drop line is a connection running between the device and the main cable. A tap is a connector that either splices into the main cable or punctures the sheathing of a cable to create a contact with the metallic core.  As a signal travels along the backbone, some of its energy is transformed into heat.  Therefore, it becomes weaker and weaker as it travels farther and farther.  For this reason there is a limit on the number of taps a bus can support and on the distance between those taps. What are Bus topology advantages and disadvantages? What are the advantages of a Bus network ( topology) ? Advantages of Bus topology : Advantages of a bus topology include ease of installation.  Backbone cable can be laid along the most efficient path, then connected to the nodes by drop lines of various lengths.

  What is the difference between star topology and mesh topology ?   In the star topology : star topology In a star topology, each device has a dedicated point-to-point link only to a central controller  usually called a hub. The devices are not directly linked to one another. Unlike a mesh topology. a star topology does not allow direct traffic between devices. The controller acts as an exchange:  If one device wants to send data to another, it sends the data to the controller, which then relays the data to the other connected device . A star topology is less expensive than a mesh topology.  In a star, each device needs only one link and one I/O port to connect it to any number of others. In a mesh topology : Mesh Topology  every device has a dedicated point-to-point link to every other device. The term dedicated means that the link carries traffic only between the two devices it connects.   😉thank you all my friends 

  Ring Topology What is Ring Topology ?  Ring Topology : In a ring topology, : each device has a dedicated point-to-point connection with only the two devices on either side of it.  How does a ring topology work? A signal is passed along the ring in one direction, from device to device, until it reaches its destination. Each device in the ring incorporates a repeater. When a device receives a signal intended for another device.  its repeater regenerates the bits and passes them along . What is Mesh Topology ?   What are the advantages and disadvantages of a mesh network ( topology) ? What are Ring topology advantages and disadvantages? What are the advantages of a Ring network ( topology) ? Why do we use ring topology? Advantages of Ring topology : A ring is relatively easy to install and reconfigure. Each device is linked to only its immediate neighbors (either physically or logically). To add or delete a device requires changing only two connections. fault isolation is simplified.  i

  Mesh Topology What is Mesh Topology ?  In a mesh topology :  every device has a dedicated point-to-point link to every other device.  The term dedicated means that the link carries traffic only between the two devices it connects. What is the example of mesh topology? What is a full mesh topology? Full mesh topology occurs when every node has a circuit connecting it to every other node in a network. A fully connected mesh topology. What are the advantages of a mesh network ( topology) ? Advantages of mesh topology : A mesh offers several advantages over other network topologies. First, the use of dedicated links guarantees that each connection can carry its own data load, thus eliminating the traffic problems that can occur when links must be shared by multiple devices. Second, a mesh topology is robust. If one link becomes unusable, it does not incapacitate the entire system. Third, there is the advantage of privacy or security. When every message travels along a dedicated line, onl

  Physical Topology types of physical topology :   The term physical topology : What meant by topology : refers to the way in which a network is laid out physically. Two or more devices connect to a link.  two or more links form a topology. The topology of a network is the geometric representation of the relationship of all the links and linking devices (usually called nodes) to one another. What are Types of network topology : There are four basic topologies possible:  1_mesh  2_star 3_bus 4_and ring. 1_mesh : What is Mesh Topology ?  In a mesh topology :  every device has a dedicated point-to-point link to every other device.  The term dedicated means that the link carries traffic only between the two devices it connects. What is the example of mesh topology? What is a full mesh topology? Full mesh topology occurs when every node has a circuit connecting it to every other node in a network. A fully connected mesh topology. What are the advantages of a mesh network ( topology) ? Advan

  Star Topology : What is star topology?  In a star topology:  each device has a dedicated point-to-point link only to a central controller, usually called a hub. The devices are not directly linked to one another. Unlike a mesh topology. a star topology does not allow direct traffic between devices. How does star topology work? The controller acts as an exchange:  If one device wants to send data to another, it sends the data to the controller, which then relays the data to the other connected device . What is the difference between star topology and mesh topology ?   In the star topology : In a star topology, each device has a dedicated point-to-point link only to a central controller  usually called a hub. The devices are not directly linked to one another. Unlike a mesh topology. a star topology does not allow direct traffic between devices. The controller acts as an exchange:  If one device wants to send data to another, it sends the data to the controller, which then relays the d

  physical structure of computer network  :    physical structures in data communications :   What is the physical structure of computer network ?   What are  network attributes ?  What are the types of connection in the network ?  1___Type of Connection :  A network is two or more devices connected through links.  What is A link ?  is a communications pathway that transfers data from one device to another. -  For communication to occur : two devices must be connected in some way to the same link at the same time. There are two possible types of connections: 1_ point-to-point  Connection  2_ and multipoint  Connection   what is difference between point to point and multipoint connection ? What is a Point to Point Connection? A point-to-point connection provides a dedicated link between two devices. The entire capacity of the link is reserved for transmission between those two devices.  Most point-to-point connections use an actual length of wire or cable to connect the two ends, but ot

  What are components of data communication ? A data communications system has five components :  1__Message : What is Message ? The message is the information (data) to be communicated.  Popular forms of information include text, numbers, pictures, audio, and video.  2__Sender: What is sender ?  The sender is the device that sends the data message.  It can be a computer, workstation, telephone handset, video camera, and so on . 3__Receiver: What is Receiver ? The receiver is the device that receives the message.  It can be a computer, workstation, telephone handset, television, and so on. 4__Transmission medium: What is Transmission medium ? The transmission medium is the physical path by which a message travels from sender to receiver.  Some examples of transmission media include : What are transmission media :  twisted-pair wire  coaxial cable  fiber-optic cable and radio waves. 5__Protocol : What is protocol ? A protocol is a set of rules that govern data communications.  It repres

  Data Flow :   Simplex, Half Duplex, Full Duplex What are the types of data flow? Communication between two devices can be  simplex ,  half - duplex , or  full-duplex. What is simplex communication? 1__Simplex:  In simplex mode : the communication is unidirectional, as on a one-way street. Only one of the two devices on a link can transmit; the other can only receive . The simplex mode can use the entire capacity of the channel to send data in one direction . What is  Half-Duplex  communication? 2__Half-Duplex :  In half-duplex mode : each station can both transmit and receive, but not at the same time. When one device is sending, the other can only receive, and vice versa. NOTE In a half-duplex transmission ,the entire capacity of a channel is taken over by whichever of the two devices is transmitting at the time. The half-duplex mode is used in cases where there is no need for communication in both directions at the same time; the entire capacity of the channel can be utilized for e

  What is data representation? Data Representation :   How is data represented in the computer? Information today comes in different forms such as text, numbers, images, audio, and video.  What is a type in data structure? 1__Text : How do you represent text on a keyboard? In data communications text is represented as a bit pattern, a sequence of bits (0s or 1s). Different sets of bit patterns have been designed to represent text symbols. Each set is called a  code  .  and the process of representing symbols is called  coding . Today, the prevalent coding system is called  Unicode , which uses 32 bits to represent a symbol or character used in any language in the world.  The American Standard Code for Information Interchange ( ASCII ) ,developed some decades ago in the United States,  now constitutes the first 127 characters in Unicode and is also referred to as  Basic Latin. What is Code ? What is Coding ? What is Uncode ? What is American Standard Code for Information Interchange (AS

Introduction to Data Communication: When we communicate :we are sharing information . This sharing can be local or remote. - local communication usually occurs face to face . - remote communication takes place over distance. What is data ? refers to information presented in whatever form is agreed upon by the parties creating and using the data. What is data ? What are Data communications : are the exchange of data between two devices via some form of transmission medium such as a wire cable. NOTE: For data communications to occur : the communicating devices must be part of a communication system made up of a combination of hardware (physical equipment) and software (programs).  The effectiveness of a data communications system depends on four fundamental characteristics: What are the fundamental characteristics of data communication? 1__Delivery: What is delivery ?  The system must deliver data to the correct destination. Data must be received by the intended device or us