Key Take aways:

• in order for datagrams to be transmitted between computer devices, the data must be 'chopped up' into small pieces known as data packets

• in order for the packets to not get lost or muddled up or go to the wrong destination, each packet must be constructed in a spacific way according to the protocols being used to transmit it.

• Generally, each packet will consist of a header, a payload and a trailer

  • Header - stores information about sender and destination as well as info about the packet itself (how many other packets there are, which number order, checksum ....)

  • payload refers to the data that is to be transferred - ie the message

  • a trailer indicates the end of a block of data that iis being sent - it can also hold error checking information

• Packet switching refers to a method of transmitting data accross a network, each packet traveling independently across the network using the fastest available route.

• Once all packets have been received they are then reconstucted and translated by the software on the destination device

• Data can travel across parallel wires simultaneously or they can travel 1 bit at a time down a single wire (serial)

  • • simplex is when data can only travel down a wire in one direction - only good over very short distances

    • full-duplex is when data can travel 1 bit at a time down a wire in both direction (like a phone)

    • half-duplex is when data can travel 1 bit at a time down a wire in both direction but only one drection at a time (like a walkie talkie)

• bits of data can be lost or transposed during transfer - it is important to check and maintain the accuracy of data

• It is also important to encrypt data to secure it as it travels and whilst it is stored.