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- 1. Sybex CCNA 640-802 Chapter 1: Internetworking i
- 2. Chapter 1 Objectives • The CCNA Topics Covered in this chapter include: – Internetworking Basics – Layered Models – The OSI Model – Ethernet Networking – Data Encapsulation – Cisco’s Three-Layer Model – Chapter 1 Written Labs and Review Questions 2
- 3. Internetworking Basics 3 How would you say the PC named Bob communicates with the PC named Sally?
- 4. Internetworking Basics 4 Switches can replace the hub, breaking up collision domains. Keep in mind that the hub used in the figure just extended the one collision domain from the switch port.
- 5. Internetworking Basics 5 Here’s a list of some of the things that commonly cause LAN traffic congestion: •Too many hosts in a broadcast domain •Broadcast storms •Multicasting •Low bandwidth •Adding hubs for connectivity to the network •A bunch of ARP or IPX traffic (IPX is a Novell protocol that is like IP, but really, really chatty. Typically not used in today’s networks.)
- 6. Internetworking Basics 6 Routers create an internetwork.
- 7. Internetworking Basics 7 There are two advantages of using routers in your network: •They don’t forward broadcasts by default. •They can filter the network based on layer 3 (Network layer) information (e.g., IP address). Four router functions in your network can be listed as follows: •Packet switching •Packet filtering •Internetwork communication •Path selection
- 9. Internetworking Basics 9 Switched networks creating an internetwork
- 10. Layered Models The Layered Approach • A reference model is a conceptual blueprint of how communications should take place. • It addresses all the processes required for effective communication and divides these processes into logical groupings called layers. • When a communication system is designed in this manner, it’s known as layered architecture. 10
- 11. The OSI Model • The OSI isn’t a physical model. Rather, it’s a set of guidelines that application developers can use to create and implement applications that run on a network. • It also provides a framework for creating and implementing networking standards, devices, and internetworking schemes. 11
- 12. The OSI Model 12 The upper layers
- 13. The OSI Model 13 The lower layers
- 14. The OSI Model 14 The Layer Functions
- 15. The OSI Model 15 Connection-Oriented Communication
- 17. The OSI Model 17 Network Layer Routing Table used in a router
- 18. The OSI Model 18 Router in an internetwork
- 19. The OSI Model 19 Data Link Layer
- 20. Binary Addressing 20 Binary to Decimal Memorization Chart 10000000 128 11000000 192 11100000 224 11110000 240 11111000 248 11111100 252 11111110 254 11111111 255 BINARY 128 64 32 16 8 4 2 1 DECIMAL 10000100 1 0 0 0 0 1 0 0 132 11010010 1 1 0 1 0 0 1 0 210 10111000 1 0 1 1 1 0 0 0 184 10100110 1 0 1 0 0 1 1 0 166 Conversion Example
- 21. The OSI Model 21 A hub in an network
- 22. The OSI Model 22 A Switch in an network
- 23. Ethernet Networking • Ethernet is a contention media access method that allows all hosts on a network to share the same bandwidth of a link. • Ethernet is popular because it’s readily scalable, meaning that it’s comparatively easy to integrate new technologies, such as Fast Ethernet and Gigabit Ethernet, into an existing network infrastructure. • It’s also relatively simple to implement in the first place, and with it, troubleshooting is reasonably straightforward. 23
- 25. Half and Full Duplex 25 Half-duplex Ethernet is defined in the original 802.3 Ethernet; Cisco says it uses only one wire pair with a digital signal running in both directions on the wire. But full-duplex Ethernet uses two pairs of wires instead of one wire pair like half duplex. And full duplex uses a point-to-point connection between the transmitter of the transmitting device and the receiver of the receiving device. Full-duplex Ethernet can be used in three situations: • With a connection from a switch to a host • With a connection from a switch to a switch • With a connection from a host to a host using a crossover cable
- 26. Ethernet Addressing 26 The MAC, or hardware, address is a 48-bit (6-byte) address written in a hexadecimal format.
- 27. Ethernet at the Physical Layer 27 The IEEE 802.3 and original Ethernet Physical layer specifications.
- 28. Ethernet Cabling 28 Ethernet cabling is an important discussion, especially if you are planning on taking the Cisco exams. Three types of Ethernet cables are available: • Straight-through cable • Crossover cable • Rolled cable We will look at each in the following sections.
- 29. Straight Through 29 The straight-through cable is used to connect • Host to switch or hub • Router to switch or hub
- 30. Crossover Cable 30 The crossover cable can be used to connect • Switch to switch • Hub to hub • Host to host • Hub to switch • Router direct to host
- 31. Rolled Cable 31 Although rolled cable isn’t used to connect any Ethernet connections together, you can use a rolled Ethernet cable to connect a host to a router console serial communication (com) port.
- 32. Using Hyper Terminal 32 Notice the settings for Hyper Terminal
- 33. What type of cable is used? 33
- 34. What type of cable is used for each connection? 34
- 35. Data Encapsulation When a host transmits data across a network to another device, the data goes through encapsulation: • It is wrapped with protocol information at each layer of the OSI model. • Each layer communicates only with its peer layer on the receiving device. 35
- 36. PDU 36
- 37. Port Numbers 37 The Transport layer uses port numbers to define both the virtual circuit and the upper-layer process.
- 38. Cisco’s Three-Layer Model 38 The following are the three layers and their typical functions: • The core layer: backbone • The distribution layer: routing • The access layer: switching
- 39. Review Question 39 Hub Hub How many broadcast domains are shown?
- 40. Review Question 40 Hub Hub Hub Hub Hub Hub Switch Switch How many collision domains are shown?
- 41. 41 Which of the hosts can transmit simultaneously without causing collisions? Hub Switch How many collision and broadcast domains are show? A F E D B C
- 42. Written Labs and Review Questions – Open your books and go through all the written labs and the review questions. – Review the answers in class. 42