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1.5 Network, Topologies, Protocols and Layers - Coggle Diagram
1.5 Network, Topologies, Protocols and Layers
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Packet Switching - most efficient use of LAN, more secure than other methods. TCP splits data into multiple packets. IP routes the individual packets in different directions. TCP checks the transmission between 2 points was successful. TCP sequences the packets back into the correct order at the destination.
Uses of IP addressing, MAC addressing, and protocols
MAC Addresses A MAC address is a unique serial number assigned to each network interface controller (NIC). This allows a network to uniquely identify any device, even when a dynamic IP address is assigned using DHCP, each time the device connects to a network. The device’s IP address changes depending on the network and the MAC address is unique to the device.
IP Addresses When connected to a network each device is given a unique IP address. A switch on the network knows where the node with this address is and routes the message to it accordingly. IP addresses can be static or dynamic. A node given a static address always keeps the same address. A node given a dynamic address has a different address assigned to it each time it connects to the network.
Protocols
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HTTP and HTTPS - Hypertext Transfer Protocol - governs communication between a webserver and a client. HTTPS (secure) includes secure encryption to allow transactions to be made over the internet.
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SMTP - Simple Mail Transfer Protocol - governs the sending of email over a network to a mail server.
POP and IMAP - Post Office Protocol and Internet Message Access Protocol - govern retrieving emails from email servers. POP is an older implementation, largely replaced by IMAP.
Ethernet - a standard for networking technologies used for communication on a wired LAN. Includes a number of associated protocols. A layer 2 standard for providing reliable, error free communication between 2 points.
Wi-Fi
Disadvantages: Speeds are slower than wired networks, relies on signal strength to WAP, signal be obstructed, less secure than wired networks.
Encryption - wireless networks broadcast data so it must be encrypted to be secure. This is done by scrambling the data into cipher text using a master "key".
Advantages: Users can move around freely, easier to set up, less expensive, convenient to use, can handle large number of users, transfer of information to social media is much easier
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Concept of Layers
There are four layers to be considered:
Application layer - encodes/decodes the message in a form that is understood by the sender and the recipient.
Transport layer - breaks down the message into small chunks (packets). Each packet is given a packet number and the total number of packets. The recipient uses this information to assemble the packets together in the correct order. It also allows the recipient to see if there are any missing packets.
Network layer - adds the sender’s IP address and that of the recipient. The network then knows where to send the message, and where it came from.
Data link layer - enables the transfer of packets between nodes on a network, and between one network and another.
Why are layers used? - It reduces complex problems into manageable sub-problems. Devices can be manufactured to operate a particular layer. Products from different vendors will work together
