![]() ![]() Follow along the pattern of 3 volts / 0 volts coming down the wire Go through all the bits, from left to right Send each byte (slight simplification):.1500 bytes * 8 bits-per-byte = 12000 bits total.Look at transmission of one 1500 byte packet.It is not required that all the packets be the same size, just that every byte of the image is sent in one packet or another. In this case, say each packet is about 1500 bytes (a typical packet size), then the bytes of the 50KB image could be divided into about 32 packets of around 1500 bytes each. The packet is the natural unit of transmission within networking. The first question is: how are the bytes of the image file on one computer sent to the other computer over the ethernet cable (or over Wi-Fi)?įor transmission, the 50KB of the image is divided into packets. Later we'll scale this up to the full Internet case of two computers on separate sides of the world. networking between two computers separated only by an ethernet cable. We'll start with the simplest case of two computer connected with an ethernet cable, and we want to send a 50KB jpeg image file from one computer to the other. Then image.jpg divides into about 32 packets.This is the "one hop" LAN case (scale up to whole world later).send an image file between ethernet connected computers An RJ-45 connector is about the size of your pinkie finger, like a wide phone wire plug. The most common form of ethernet wiring is 100base-T (100 megabit) with "RJ-45" connectors on the ends. A typical LAN application is networking the computers in one room or in one floor of a building. Ethernet cable lengths are typically limited to 100 meters, in keeping with its "local" orientation. Networking speeds generally quoted in bits-per-second, as aboveĮthernet cables plugged into the back of a Wi-Fi router (Linksys WRT54g)Įthernet is an extremely common and influential wired LAN standard, so we'll start there.letter "b" confusion - note "mbps" and "gbps" refer to bits not bytes.1 gigabit, 1 billion bits per second, aka 1 gbps, 1000 mbps 100 megabits, 100 million bits per second, aka 100 mbps Wires about as thick as a drinking straw.Very popular wired LAN technology, 1974.We'll start by looking at LAN (local area network) technology - connecting 2-50 computers in a house or on one floor of a building. Later, show scale up to world-wide internet.We'll look at this fetch-web-page example a few different ways to see how the internet works. Your browser gets back all this data and formats it for your screen so you can read the text, click links etc. The machine sends back a large response which is the web page - maybe 200KB - and ends the call. The request is small, about 1KB (1 kilobyte). Suppose your laptop is connected to the internet, and you type "" into your browser - what happens? Your computer contacts the computer "- placing a "call" in effect - and sends a request for the main web page. The Internet is like a global phone system for computers: a computer can "call" another computer on the internet to get or send a little information. When you wake up, how long passes before using a network?Ĭomputer networks are complicated in the details, but the basic ideas of how it all works are surprisingly simple, and that's what we're going to study.Worth knowing the basics, you are using the network constantly.A computer places a "call" to exchange data with another computer.Computer Networks are like a phone system for computers.Receiving Device’s IP address: 192.168.0.Here we look at the most basic features of networking and packets.Receiving Device’s Port Number: 20 (using udpAddrMake ).Sending PDMM’s Port Number: 10 (using udpCreate and create the Socket to send Data). ![]() PDMM to PC communications – key function blocks Note: You may need to use different IP Addresses that fits with your network addressing scheme. The program “ udpProgram” in the project UDP test Send-Receive First Transmission Each Way.kas has been added to a. This application note uses the PC utility Packet Sender (download at ) to perform simple communications between a PxMM and a PC. ![]()
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