Lecture 3 Network Protocols and Communications

1. Lecture 3Network Protocols and Communications Objectives: • Explain how rules are used to facilitate communication. • Explain the role of protocols and standards organizations in facilitating interoperability in network communications. • Explain how devices on a LAN access resources in a small to medium-sized business network.

2. The RulesData Networks • Data networks are systems of end devices, intermediary devices, and the media connecting the devices. For communication to occur, these devices must know how to communicate. • These devices must comply with communication rules and protocols. TCP/IP is an example of a protocol suite.

3. The RulesElements of Communications • Communication begins with a message, or information, that must be sent from one individual or device to another using many different communication methods. • All of these methods have 3 elements in common: - message source, or sender - destination, or receiver - a channel

4. The RulesMessage Delivery Options

5. ProtocolsRules that Govern Communications

6. ProtocolsNetwork Protocols • How the message is formatted or structured • The process by which networking devices share information about pathways with other networks • How and when error and system messages are passed between devices • The setup and termination of data transfer sessions

7. ProtocolsInteraction of Protocols • Application Protocol – Hypertext Transfer Protocol (HTTP) • Transport Protocol – Transmission Control Protocol (TCP) • Internet Protocol – Internet Protocol (IP) • Network Access Protocols – Data Link & Physical layers

8. Protocol SuitesProtocol Suites and Industry Standards • A standard is a protocol used in the networking industry • Many of the protocols that comprise a protocol suite reference other widely utilized industry standards • The use of standards in developing and implementing protocols ensures that products from different manufacturers can work together for efficient communications • Institute of Electrical and Electronics Engineers (IEEE) or the Internet Engineering Task Force (IETF)

9. Protocol SuitesProtocol Suites and Industry Standards

10. Protocol SuitesTCP/IP Protocol Suite and Communication

11. Reference ModelsThe Benefits of Using a Layered Model • Provides a common language to describe networking functions and capabilities. • Assists in protocol design: protocols that operate at a specific layer have defined interface to the layers above and below. • Prevents technology or capability changes in one layer from affecting other layers. • Fosters competition: products from different vendors can work together.

12. Reference ModelsThe OSI Reference Model • The OSI model describes the processes of encoding, formatting, segmenting, and encapsulating data for transmission over the network.

13. Reference ModelsThe TCP/IP Reference Model • The TCP/IP protocol suite is an open standard protocol that has been endorsed by the networking industry and ratified, or approved, by a standards organization.

14. Reference ModelsComparing the OSI and TCP/IP Models TCP/IP combines the presentation and session layer issues into its application layer Both have comparable transport and network (Internet) layers TCP/IP combines the OSI data link and physical layers into its network access layer

15. Data EncapsulationCommunicating the Messages • 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 destination protocol stack. • Segmenting message benefits • Different conversations can be interleaved • Increased reliability of network communications • Segmenting message disadvantage • Increased level of complexity

16. Data EncapsulationProtocol Data Units (PDUs) • Protocol Data Units (PDUs) are named according to the protocols of the TCP/IP suite: data, segment, packet, frame, and bits.

17. Moving Data in the NetworkAccessing Local Resources • Network Address • Source IP address • Destination IP address • Data Link Address • Source data link address • Destination data link address

18. Accessing Local ResourcesCommunicating with Device / Same Network

19. Accessing Local ResourcesMAC and IP Addresses ARP Request R1 192.168.1.1 11-11-11-11-11-11 PC1 192.168.1.110 AA-AA-AA-AA-AA-AA S1 R1 PC2 192.168.1.111 BB-BB-BB-BB-BB-BB FTP Server 192.168.1.9 CC-CC-CC-CC-CC-CC

20. Accessing Remote ResourcesDefault Gateway 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

21. Accessing Remote ResourcesCommunicating Device / Remote Network

22. Animation • 3113 Message encoding • 3114 Letter • 3242 OSI • 3323 ARP Activity • 3224 Protocol and layers • 3245 OSI layer functions • 3315 PDU

23. Introduction to Networks Chapter 3: Network Protocols and Communications Further Exploration …

24. Network Protocols and StandardsStandards Organizations

25. Standards OrganizationsOpen Standards • The Internet Society (ISOC) • The Internet Architecture Board (IAB) • The Internet Engineering Task Force (IETF) • Institute of Electrical and Electronics Engineers (IEEE) • The International Organization for Standards (ISO)

26. Standards OrganizationsISOC, IAB, and IETF

27. Standards OrganizationsIEEE • 38 societies • 130 journals • 1,300 conferences each year • 1,300 standards and projects • 400,000 members • 160 countries • IEEE 802.3 • IEEE 802.11

28. Standards OrganizationsISO

29. Standards OrganizationsOther Standards Organization • The Electronic Industries Alliance (EIA) • The Telecommunications Industry Association (TIA) • The International Telecommunications Union – Telecommunications Standardization Sector (ITU-T) • The Internet Corporation for Assigned Names and Numbers (ICANN) • The Internet Assigned Numbers Authority (IANA)

30. Accessing Remote ResourcesUsing Wireshark to View Network Traffic