CHEM237 Lecture 15: CS100 Module 5
27 Jan 2019
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Document Summary
Ethernet: need device than can transfer info through the cable, connection device requires unique identifier mac (media access control) address, speed ratings . Wifi voice: just a radio wave, can be sent for kilometers but uses a lot of power, how does it work, need an access point, broadcasts a name, additional security, very similar to ethernet. Cellular (3g/lte: electromagnetic radiation, 3g 3rd generation, long-term evolution (lte, range: kilometers, nosier environments, more power, unique identifier: imei (international mobile station equipment identity, wifi takes more power than 3g. Tcp: transmission control protocol (alternative to this is udp, user datagram protocol) Tcp: quality control, break large message into smaller packers (numbered, acknowledge received packers, request missing packets, reassemble large message from packers, tcp breaks message into little packets. Ip: ip address, sends packets of information from one source to another, packets contain addressing information and data, 4 numbers, each in the range 0 255 256 options, but are running out, plan b.
