Network Protocols KS4
- 1. NETWORK PROTOCOLS FOR KS4 OCR GCSE COMPUTER SCIENCE (J277) MRS KNIGHT
- 2. STARTER NETWORKS . . . How much can you recall? Networks, LANs & WANs Quiz (Google Form)
- 3. QUICK RECAP OF LAST LESSON IP Address Internet Protocol address Unique address for each device on a network. Each address has 4 sets of up to 3 digits (IPv4), each with a maximum value of 255. Used to route packets on a WAN. MAC Address Media Access Control Every individual device in the world has a unique MAC Address. Used to route frames on a LAN, directed by the switch. TCP / IP Transfer Control Protocol / Internet Protocol TCP - Rules for communicating over the internet. IP - Rules for communicating over the internet
- 4. LEARNINGOBJECTIVES •Define network protocols and why they are needed. •Identify and explain standard internet protocols in the application layer, e.g. HTTP, HTTPS, FTP, SMTP, POP, and IMAP. KEY WORDS: Protocol, DNS, HTTP, HTTPS, FTP, POP, IMAP, SMTP, TCP/IP, MAC addresses, layers.
- 5. SUCCESS CRITERIA ALL will have a basic understanding of why protocols are used. ALL will be aware of some protocols and what they are used for. MOST should be able to explain why protocols are used. MOST should be able to identify and explain specific protocols. SOME could give detailed explanations with examples of why protocols are used. SOME could give detailed explanations for most protocols.
- 6. WHAT ARE NETWORK PROTOCOLS? 1. A network PROTOCOL is set of RULES for communication over a network. 2. This STANDARDISATION allows interoperability between systems locally and across the globe. 3. Protocols describe HOW the standards work. QUESTION: Why do we need these standards?
- 7. 10-MINUTE TASK CREATE A PROTOCOL Get into groups of 3-4 Create a protocol for sending simple text messages across a network. Write out the steps that your protocol will follow to send the message. Test your protocol by sending a message across your group. REQUIREMENTS 1. Send a message of at least 80 characters including spaces. 2. Split your message into ‘chunks’. 3. Each ‘chunk’ can contain a maximum of 8 characters. 4. ‘Chunks’ might not reach the other computer in order. 5. Both the sender and the receiver of the message must be confident that the full message has been received.
- 8. TCP/IP – 4 LAYER PROTOCOL STACK APPLICATION LAYER TRANSPORT LAYER INTERNET LAYER LINK LAYER PROVIDES END-TO-END COMMUNICATION BETWEEN 2 HOSTS. DETERMINES LANGUAGE, PACKET SIZE, ETC. ADDRESSES AND PACKAGES DATA READY FOR TRANSMISSION. ROUTES PACKETS ACROSS THE NETWORK. PHYSICAL HARDWARE, I.E. ROUTERS, CABLES, NETWORK INTERFACE CARDS (NIC). DHCP, DNS, HTTP, HTTPS, FTP, SMTP, POP, IMAP TCP, UDP IP4 OR IP6 TWISTED PAIR, WI-FI, FIBRE. PROVIDES USER INTERFACE, I.E. WEB BROWSERS AND EMAIL PROGRAMS.
- 9. Hypertext Transfer Protocol Hypertext Transfer Protocol Transfers non-secure web pages between web servers and web browsers (client) across the internet. The data is not private. Securely transfers encrypted web pages between web servers and web browsers (client) across the internet. The data remains private. HTTP HTTP VERSUS HTTP Image courtesy of Rahul Kumar Mandal at medium.com 2021. HTTP/HTTPS is mainly used to access web pages but is also the protocol used for various apps too.
- 10. Enables sending, receiving and sharing of files across the internet. FTP is not encrypted and therefore insecure. Image courtesy of EDUCBA.COM 2021. File Transfer Protocol FTP
- 11. SMTP SIMPLE MAIL TRANSFER PROTOCOL Used by email client application to send email. SMTP server listens for SMTP request from email client. SMTP relays emails via email servers throughout the internet. Image courtesy of GEEKFLARE.COM 2021.
- 12. Image courtesy of Tech4Law.co.za 2021. INTERNET MESSAGE ACCESS PROTOCOL POST OFFICE PROTOCOL IMAP creates a COPY of the email on the device. IMAP leaves a COPY on the mail server. After opening the email, it CAN be viewed on other devices too (unless it is deleted). POP does NOT create a client copy of the email. POP does NOT leave a copy on the mail server. After opening the email, it CANNOT be viewed on other devices. VERSUS POP controls the fetching/download of emails from the mail server to the client. IMAP controls the download/upload of emails to and from the mail server.
- 13. SUMMARY - WHY TCP/IP ? APPLICATION LAYER TRANSPORT LAYER INTERNET LAYER LINK LAYER PROVIDES END-TO-END COMMUNICATION BETWEEN 2 HOSTS. DETERMINES LANGUAGE, PACKET SIZE, ETC. ADDRESSES AND PACKAGES DATA READY FOR TRANSMISSION. ROUTES PACKETS ACROSS THE NETWORK. PHYSICAL HARDWARE, E.G. ROUTERS, CABLES, NETWORK INTERFACE CARDS (NIC). DHCP, DNS, HTTP, HTTPS, FTP, SMTP, POP, IMAP TCP, UDP IP4 OR IP6 TWISTED PAIR, WI-FI, FIBRE. PROVIDES USER INTERFACE, I.E. WEB BROWSERS AND EMAIL PROGRAMS.
- 14. RETRIEVAL GRID (PLENARY) HTTP DNS IMAP FTP SMTP HTTPS IP TCP POP
- 15. RETRIEVAL GRID ANSWERS HYPERTEXT TRANSFER PROTOCOL DOMAIN NAME SERVER INTERNET MESSAGE ACCESS PROTOCOL FILE TRANSFER PROTOCOL SIMPLE MAIL TRANSFER PROTOCOL HYPERTEXT TRANSFER PROTOCOL (SECURE) INTERNET PROTOCOL TRANSFER CONTROL PROTOCOL POST OFFICE PROTOCOL
- 16. CONFIDENCE LEVEL? VERY CONFIDENT Understood ALL of it, very confident. FAIRLY CONFIDENT Understood MOST of it, fairly confident. OKAY Understood SOME of it and need some support. NEXT LESSON: Threats to computer systems and networks. HOME WORK: Watch video: Threats to Networks (Research threats – google doc).
Editor's Notes
- #4: All communication requires rules to determine how the communication is made. Rules that govern communication are known as protocols. There are many types of protocol but the ones that govern addressing are: Internet Protocol (IP) When connected to a network each device is given a unique IP address. Address consists of 4 sets of up to 3 digits, each with max value of 255 (separated by dots). Dynamic IP addressing allows more devices to connect than there are available addresses. When a device disconnects from the network, its address is freed up for another device to use. When the first device reconnects it is assigned any free address. This method is called IPv4, which when devised, was deemed to be enough. Massive increase in internet devices mean IPv4 run out of addresses. IPv6 includes 6 sets of 3 digits, greatly increases the number of possible addresses to trillions. Media Access Control (MAC) Unique serial number assigned to each network interface controller (NIC). Allows network to identify any device, even when a dynamic IP address is assigned using DHCP, each time the device connects to a network. Device’s IP address changes depending on network & MAC address is unique to device. A MAC address consists of a string of hexadecimal numbers, e.g. 1A:5B:6H:98:78:35 MAC address is assigned by manufacturer of NIC & cannot be changed. If device has more than one NIC, e.g. a wired NIC & a wireless NIC, each NIC has its own MAC address.
- #5: Ask students to write these objectives down in their books.
- #7: OCR definitions is “A network PROTOCOL is set of RULES for communication over a network.” This and only this will receive the exam mark.
- #8: Group activity: 10-Minute Task (NB. Students to be grouped as per covid seating plan to maintain minimal contact.) 5 minutes to complete task 5 minutes to present the task How will the receiver know what order to reassemble the chunks in? What information needs to be with their chunks to make this possible? What does this mean will happen to the number of chunks sent? Many? Lost? Different routes? How will the sender AND receiver know that the message has been fully received? Could we send some information at the start of the protocol so that the receiver knows how much to expect? How can we ensure that any confirmation messages are received at both ends? Responses from 5 randomly picked groups; 1 person per group nominated to report back (1 minute per team). How successful was their protocol? Did they follow all the steps as described? Did they find any problems? What would improve the protocol?
- #9: Impress the importance of the Transmission Control Protocol/Internet Protocol (TCP/IP) model layers and how it breaks the sending of messages into smaller, separate tasks/chunks. Each component handles a different part of the communication. 4 TCP/IP Layers: Application: Encodes/decodes message in the format understood by the sender and the recipient. Transport: Breaks message into small chunks (packets). Network: Adds the sender and recipients IP addresses. The network then knows where to send the message, and where it came from. Data Link: Transfers packets between nodes on a network, and between one network and another. Layering allows standards to be developed, but also allows scope to be adapted for new hardware and software over time. For example, different software packages (applications) may use the same transport, network and link layers but have their own application layer. The way the program encodes the message changes - the rest of communication method remains the same. This allows interoperability. Changing from IPv4 to IPv6 addressing only affects the network layer, yet other layers remain unaffected. This allows improvements to be made without having to redefine whole communication methods.
- #10: Hypertext Transfer Protocol - governs communication between a webserver and a client. HTTP Transfers non-secure web pages between web servers & web browsers (client) across the internet. The data is not private. HTTPS (secure) includes secure encryption to allow transactions to be made over the internet. HTTPS Securely transfers encrypted web pages between web servers & web browsers (client) across the internet. The data remains private.
- #11: FTP: Enables sending, receiving and sharing of files across the internet. FTP is not encrypted & therefore insecure.
- #12: SMTP: Used by email client application to send email. SMTP server listens for SMTP request from email client. SMTP relays emails via email servers throughout the internet.
- #13: POP is an older implementation, largely replaced by IMAP. POP: Fetching/downloading emails from mail server to client. Does NOT create client copy. Does NOT leave a copy. After opening, email CANNOT be viewed elsewhere. IMAP: Download/upload emails to & from mail server. IMAP creates device COPY. IMAP leaves COPY on mail server. After opening, email, CAN be viewed elsewhere (unless deleted).
- #14: Reiterate the importance of the Transmission Control Protocol/Internet Protocol (TCP/IP) model. Layers break up the sending of messages into separate components and tasks. Each component handles a different part of the communication. Allows for easier error fixes. 4 TCP/IP Layers: Application: Encodes/decodes message in the format understood by the sender and the recipient. Transport: Breaks message into small chunks (packets). Network: Adds the sender and recipients IP addresses. The network then knows where to send the message, and where it came from. Data Link: Transfers packets between nodes on a network, and between one network and another. Layering allows standards to be developed, but also allows scope to be adapted for new hardware and software over time. For example, different software packages (applications) may use the same transport, network and link layers but have their own application layer. The way the program encodes the message changes - the rest of communication method remains the same. This allows interoperability. Changing from IPv4 to IPv6 addressing only affects the network layer, yet other layers remain unaffected. This allows improvements to be made without having to redefine whole communication methods.
- #15: HTTP: Transfers non-secure web pages between web servers & web browsers (client) across the internet. The data is not private. HTTPS: Securely transfers encrypted web pages between web servers & web browsers (client) across the internet. The data remains private. FTP: Enables sending, receiving and sharing of files across the internet. FTP is not encrypted & therefore insecure. SMTP: Used by email client application to send email. SMTP server listens for SMTP request from email client. SMTP relays emails via email servers throughout the internet. POP: Fetching/downloading emails from mail server to client. Does NOT create client copy. Does NOT leave a copy. After opening, email CANNOT be viewed elsewhere. IMAP: Download/upload emails to & from mail server. IMAP creates device COPY. IMAP leaves COPY on mail server. After opening, email, CAN be viewed elsewhere (unless deleted).
- #16: HTTP: Transfers non-secure web pages between web servers & web browsers (client) across the internet. The data is not private. HTTPS: Securely transfers encrypted web pages between web servers & web browsers (client) across the internet. The data remains private. FTP: Enables sending, receiving and sharing of files across the internet. FTP is not encrypted & therefore insecure. SMTP: Used by email client application to send email. SMTP server listens for SMTP request from email client. SMTP relays emails via email servers throughout the internet. POP: Fetching/downloading emails from mail server to client. Does NOT create client copy. Does NOT leave a copy. After opening, email CANNOT be viewed elsewhere. IMAP: Download/upload emails to & from mail server. IMAP creates device COPY. IMAP leaves COPY on mail server. After opening, email, CAN be viewed elsewhere (unless deleted).
- #17: We learned about network protocols today. Next lesson, we will learn about threats to computer systems and networks. Assessment Snapshot: Pull example emoji faces and ask them to copy as per their own feelings about the topic. For the ‘Starter’ at the beginning of the next lesson, ask learners what they can recall from the last lesson on network protocols. Ask different learners to come out “Be Mrs Knight” and give 1 minute mini teach on the different protocols.