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Chapter 1 : Explore the Network, image, image, image - Coggle Diagram

- - - - A network is a group of computer and devices that communicate by wire and cable. It can be as small as two computer connected by a cable in a home office or as large as several thousand computers connected across the world via a combination of cable, phone lines and cellular links
  - - - Internet
        
        connecting computer to any other computer in the world
        
        via router and servers
        
        they can send and receive all kind of information
      - Difference between extranet and intranet
        
        a. Extranet
        
        Share content accessed by group through cross enterprise
        boundaries.
        
        b. Intranet
        
        Share content accessed by members within a single
        organization
  - - - a. Fault Tolerance
        -Fault Tolerance is that the Internet is always available to the millions of users who rely on it.
        -Requires a network architecture that is built to be fault tolerant.
        -is one that limits the effect of a failure, so that the fewest number of devices are affected by it.
        -also built in a way that enables quick recovery when such a failure occurs.
        -depend on multiple paths between the source and destination of a message.
        -If one path fails, the messages can be instantly sent over a different link.
      - b. Scalability
        
        scalable network can expand quickly to support new users and applications.
        
        without affecting the performance of the service being delivered to existing users.
      - c. Quality Of Service
        -is also an ever-increasing requirement of networks today.
        -New applications available to users over internetworks,
        -such as voice and live video transmissions.
      - d. Security
        -Securing a network infrastructure includes physically securing devices that provide network connectivity.
        -preventing unauthorized access to the management software that resides on those devices.
  - - - Fundamental Of Network Models:
        
        b)Clients Server Networks
        
        use a central computer , known as server
        
        to facilitate communication and resource sharing between other computers on the network , client.
        
        A network that uses a server to enable clients to share data, data
        storage space, and devices is known as a client/server network.
        
        A client/ server archicture used to refer to design of a network, clients rely on servers for resource sharing and processing.
        
        a)Peer -to- peer Networks(P2P)
        
        Advantages:
        
        Easy set up
        
        Less Complexity
        
        Lower Cost
        
        Can be used for simple task
        
        Disavantages:
        
        No centralized administration
        
        Not secure
        
        Not Scalable
        
        All Devices will act both whuch can slow their performance
    - - Host can be used as client, server or both. For example , elements of client/server are client , server, workstation, network operating system, host, node ,connectivity device ,backbone, segment, tapology , protocol, transmission media .Next for fundamental of network models have two, which is peer-to-peer networks and clients server networks. For clients server networks can use a central computer that known as server for facilitate communication and resource sharing between other computers on the networks, which is client and the server are enable client to share data ,data storage space or everything that known as a client/server network. Each of it has many advantages and disadvantages of the networks.
  - - - Network help us to learn, communicate, work and play. It have a lot of advantages like share resources but still have disadvantages like data security concern and undesirable sharing
- - - - Receiver
        
        The device which receives the data messages.
      - Transmission Medium
        
        The physical path by which a message travels from
        sender to receiver.
      - Sender
        
        The device which sends the data messages
      - Protocol
        
        A set of rules that governs the data communications.
      - Message
        
        The information to be communicated like text, pictures, video
    - - Message delivery option
        
        Multicast Message (one-to-many delivery)
        
        Unicast Message ( one-to-one delivery)
        
        Broadcast Message (many-to-many delivery)
      - Message Formatting and Encapsulation
      - Message encoding
        
        Encoding between hosts must be in
        appropriate format for the medium.
      - Message Timing
        
        Access method
        
        Flow control
        
        Response Timeout
      - Message size
        
        Long messages must also be broken into smaller
        pieces to travel across a network.
    - - Destination (Receiver)
        
        The destination receives the message
        and interprets it.
      - Channel (Media)
        
        Provides the pathway over which the message
        can travel from source to destination.
      - Source (Sender)
        
        Message sources are people, or electronic devices that need to communicate a message to other individuals or devices
    - - Before communicating with one another, individuals must use established rules or agreements to govern the conversation. Protocols are necessary for effective communication.The protocols used are specific to the characteristics of the communication method, including the characteristics of the source, destination and channel.
  - - - Network Protocols define a common format.
        
        A common format and set of rules of
        exchanging messages between devices.
      - Common networking protocols
        
        Hypertext Transfer protocol (HTTP)
        
        Transmission control Protocol (TCP)
        
        Internet Protocol (IP)
      - Protocols Interaction
        HTTP - an application protocol that governs the way a
        web server and web client interact.
        TCP - transport protocol that manage the individual
        conversation.
        IP - encapsulates the TCP segment into packets,
        assigns addresses, and delivers to the destination
        host.
        Ethernet - allow communication over a data link and
        physical transmission of data on the network
        media.
    - - Protocols suites and Industry standard
        
        a set of protocols that work together to provide comprehensive network communication services.
        
        TCP/IP protocol suite is an open standard, they are available free and any vendor can implement these protocols in hardware or software.
      - Development of TCP/IP
        
        Advanced Research projects agency network (ARPANET) was the predecessor to today's internet .
      - TCP/IP communication process
        These are the procedure when sending data from a web server to a client:
        
        Webserver prepare HTML. The HTTP application layer protocol sends the data to transport layer.
        
        The transport layer break the data into segments and identifies each.
        
        next the IP source and destination addresses are added, creating an IP packet.
        
        The ethernet information is then added creating the ethernet frame, or data link
        frame.
        
        When receiving the data link frames from the web server, the client processes and removes each protocol.
        
        first the ethernet header is removed
        
        then the IP header
        
        then the transport layer header
        
        finally HTTP information is processed and sent to the client's web browser.
  - - - Application - contains protocols used for process-toprocess communications.
      - Presentation - provides for common representation of the data.
      - Session - provides services to the presentation layer to organize its dialogue and to manage data exchange.
      - Transport - defines services to segment, transfer, and reassemble the data.
      - Network - provides services to exchange the individual pieces of data over the network between identified end devices.
      - Data Link - provides methods for exchanging data frames between devices over a common media.
      - Physical - describes the mechanical, electrical, functional, and procedural means to transmit bits across physical connections.
      - The 7 Layer of OSI
    - - Open Standard.
      - Also called The TCP/IP Model or the Internet Model.
      - Created in the early 1970s for internetwork communications.
    - - OSI model
        the network access layer
      - TCP/IP model
        further divided to describe discrete functions that must occur at these layers.
      - Similarities
        
        share similar architecture.
        
        share a common application layer
        
        Both models have comparable transport and network layers.
        
        Knowledge of both models is required by networking professionals.
      - Differences
        
        Protocol standard
        
        combines the presentation and session layer issues into its application layer
        
        combines the OSI data link and physical layers into the network access layer
        
        a simpler model
    - - Summary
        Associating the protocols that set the rules of data communications with the different layers of these models is useful in determining which devices and services are applied at specific points as data passes across LANs and WANs. TCP/IP has 4 layer there are Application layer, transport layer, internet layer, and network access layer. The OSI has 7 layer there are application layer, presentation layer, session layer, transport layer, network layer, data link and physical layer. TCP and OSI have similarities and differences.