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networks - Coggle Diagram

- - - - A router stores the addresses of computers on the network and transfers data between devices.
      - Gateways
        
        A gateway joins together two networks that use different base protocols, e.g. links a LAN to WAN.
        
        Bridge
        
        A bridge joins together two networks that use the same base protocols, e.g. links LAN to LAN.
- - - - Disadvantages
        
        If any of the computer systems fail, the ring is broken and data cannot be transmitted efficiently
        if a problem goes down in the main cable or connection the whole entire network goes down
        It is difficult to troubleshoot the ring
        Because nodes are wired together, to add another you must shut down the network
      - The transmission of data is simple as packets travel in one direction only, so no collisions.
        Data is quickly transferred without a bottleneck – consistent data transfer speeds
        Adding additional nodes has very little impact on bandwidth
- - - - Contents of a packet
        
        Length is the number of bits in the packet
        Packet ID is needed so that, afterwards, data from multiple packets can be arranged into the correct order
        Source address is the IP address of the device that sent the data.
        Destination address is the IP of the device that should receive the data
        Protocol is an indication of which protocol (HTTP, FTP, SMTP, etc.) has been used to form the packet.
        Data is the reason a packet is being sent in the first place, Eventually, all packet components are discarded except for the data itself.
        Checksum is a technique that verifies that the data that was sent matches the data that was received
- - - - Advantages
        
        easy to add more computer system without
        disturbing the the network quick and easy to set up suitable for temporary networks
        Cost-effective as less cabling is needed
        
        disadvantages
        
        It is difficult to troubleshoot the bus if there’s a fault
        limited cable lengths and number of stations performance degrades as additional computers are added
        if there is a problem in the main cable or connection the whole network will go down
        Low security
        Proper termination is required
        Data collisions are more likely, which causes the network to slow down. A collision is when two computers try to send a packet at the same time
      - The computers (nodes) are connected to a single cable on which data can be sent, called the bus.
        The bus has terminators on each end, which are needed to close each end of the cable.
        The bus carries data packets along the cable.
        As the packets arrive at each computer system, it checks the destination address contained in the packet to see if it matches its own.
        If the address does not match, the computer system ignores the packet. If the address of the computer system matches that contained in the packet, it processes the data.
- - - - good performance/fast network speed
        easy to set up
        easy to add more computer systems without taking the network down
        failure of workstations will have no
        effect on the network
        Minimal network collisions
        Better security
        
        Sending data over a Star network
        
        Computer A adds computer D’s address to packet
        Computer A sends packet to switch
        Switch looks at address on packet
        Switch compares to stored list of addresses on network
        Switch forwards packet to computer D’s address
      - disavantages
        
        Expensive to install as more cable is required
        Extra hardware required, such as a hub