generic model, supports connectionless and conection oriented services, changes at one layer do not affect the others/// dis: very complex, duplication of services in different layers, purely a theorethical model
industry standard model, interoperable, scalable client=oriented architecture///// dis: not generic in nature but rather protocol dependend, not optimized for small networks, does not distinghuish phisical layers and data link layers
hamming code: how many bits can be detected and how manye can be corrected
key points: fixed set of states, one state at a time, a sequence of inputs is sent to the machine, every state has a set of transitions and every transition is associated with an input and pointing to a state