Network protocols & communications

1. Network protocols & communications Chapter 3 Intro to Routing & Switching

2. objectives • Upon completion of this chapter, you should be able to: • Explain why protocols are necessary in communication • Explain the role of standards organizations in establishing protocols • Explain how the TCP/IP model and the OSI model are used for standardization of communication • Explain how data encapsulation allows data to be transported • Explain how local hosts access local resources • Explain how local hosts access remote resources

3. What is communication?

4. 3.1.1 The Rules

5. The rules • Must follow same rules to communicate • Name some ways of everyday communicating • What do you need to communicate? • Network communication is similar • Source/destination • Rules of how message is sent include: • Message encoding; Message formatting and encapsulation; Message size; Message timing; Message delivery options

6. Message encoding • ENCODING • Converting info for travel on media • Ex: bits into electricity, light, radio waves • DECODING • Interpret info from media • Ex: electricity, light, radio waves into bits

7. Message formatting & encapsulation FRAME

8. Message size • What if books where one long sentence? Hard to understand. • When you speak, messages broken up in sentences • Easier to process in smaller parts • Size of frames small • Messages broken into small pieces • Each segmented message is encapsulated & sent • Frames de-encapsulated, put back together & read at destination

9. Message timing • How fast or slow to talk • Access method • Speak at same time= collision • Wait turn to speak • Flow control • Speak fast= confusion • Control flow of data • Response timeout • No response= repeat question • Rules for how long to wait for response & retransmit

10. Delivery options

11. review • Data is packaged up. What is this process called? • Encapsulation • The message and addressing info is encapsulated into a ___________. • Frame • Converting bits for travel on an Ethernet cable is known as what? Also, what is it converted into? • Encoding; electricity

12. review • What kind of message goes to everyone? • Broadcast • A room is filled with 25 computers. PC1 sends a message to PC4, 7, 10, 15, and 20. What kind of message has been sent? • Multicast • Too much data is being sent too quickly between two communicating devices. If you don’t want dropped packets, what timing method would control how much is being sent at a time? • Flow control

13. 3.2.1 protocols

14. Common protocols • Many protocols work together to send data

15. 3.2.2 Protocol suites

16. Protocol suite • Set of protocols that work together • Standards developed to allow interoperability • IEEE • Proprietary protocols • One vendor controls how it operates • AppleTalk & Novell are examples • We’ll look at TCP/IP, an open standard

17. Tcp/ip model

18. Data communication

19. 3.2.3 Standards organizations

20. Standards • Open standards are good • ISOC- Internet Society • IEEE- electrical standards • 802.3 Ethernet • 802.11 Wireless • ISO- standards/ created OSI model • EIA/TIA- electrical & telecommunications • ICANN- IP addressing/domains • IANA- runs under ICANN

21. review • Define a proprietary protocol. • Protocol that an organization controls • What is the IEEE standard for Ethernet? • 802.3 • What is the IEEE standard for wireless? • 802.11 • You are requesting a web page… • What protocol is used 1st? • HTTP • What protocol ensures delivery of it? • TCP • What protocol helps find the best path? • IP • What protocol formats it for transmission? • Ethernet

22. 3.2.4 Reference models

23. Tcp/ip model

24. Tcp/ip model

25. Osi model

26. Comparing the models

27. activity

28. review • What is layer 4 of the OSI model? • Transport • What is layer 3 of the OSI model? • Network • Which layer finds the best path? • Network • Which layer is responsible for delivery of the data? • Transport • A piece of data at a layer is known as what? • PDU

29. review • What layer turns data into bits for transmission on a cable, for example? • Physical • Where are IP addresses? • Network • HTTP is at which layer? • Application • Where is data divided into segments? • Transport • What is the PDU at layer 2? • Frames

30. 3.3.1 Data encapsulation

31. encapsulation • Data divided into smaller segments • Many conversations can be sent • Multiplexing • Only parts of missing message can be resent

32. PDU

33. encapsulation

34. De-encapsulation

35. activity • Complete the activity on 3.3.1.5

36. review • In the TCP/IP model… • Data is sent from the Internet layer to the Network Access layer. • False • Segments are sent from the Transport layer to the Internet layer. • True • At which layer of the TCP/IP model would you find the logical address, or IP address? • Internet layer • Name the OSI model from 7 to 1

37. 3.3.2 Accessing local resources

38. addressing

39. Local transmission- arp • To find the MAC address of a device within your network… • ARP request sent as a broadcast • DOES NOT GO OUTSIDE A NETWORK • Includes the IP of the destination • Every NIC looks at it; only one with that IP will respond with its MAC address

40. 3.3.3 Accessing remote resources

41. Get out of the network! • If destination IP is outside of network, it gets sent to the default gateway address • Router port to get out of the network R2 172.16.1.99 22-22-22-22-22-22 PC 1 192.168.1.110 AA-AA-AA-AA-AA-AA R1 192.168.1.1 11-11-11-11-11-11 Web Server 172.16.1.99 AB-CD-EF-12-34-56 FTP Server 192.168.1.9 CC-CC-CC-CC-CC-CC PC 2 192.168.1.111 BB-BB-BB-BB-BB-BB

42. Proxy arp • You don’t know the destination MAC • ARP can’t be sent outside of the network • The DG’s MAC address is substituted

43. review • Which process finds out the MAC address of a PC on the local network? • ARP • At the Internet & Network layer, which address is logical? • IP address • Which address is physical? What layer of the OSI? • MAC; Data Link • When sending data outside your network, which address is used for the destination MAC? • Default gateway MAC address

44. Review & study • Complete the study guide handout • Take the quiz on netacad.com • Jeopardy review

45. summary In this chapter, you learned: • Devices must comply with communication rules and protocols. TCP/IP is an example of a protocol suite. • Most protocols are created by a standards organization such as the IETF or IEEE. • The most widely-used networking models are the OSI and TCP/IP models.

46. summary • Data that passes down the stack of the OSI model is segmented into pieces and encapsulated with addresses and other labels. • The process is reversed as the pieces are de-encapsulated and passed up the protocol stack. • The OSI model describes the processes of encoding, formatting, segmenting, and encapsulating data for transmission over the network. • The TCP/IP protocol suite is an open standard protocol.

47. summary • The names of layers in the OSI & TCP/IP models. • Protocol Data Units (PDUs) are data, segment, packet, frame, and bits. • ARP & Proxy ARP are used in sending data. • Applying models allows individuals, companies, and trade associations to analyze current networks and plan the networks of the future.

48. Network protocols & communications Chapter 3 Intro to Routing & Switching