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CCNA Chapter1
This document provides an overview of the contents of the Sybex CCNA certification course. It outlines topics covered like TCP/IP fundamentals, routing, switching, VLANs, and security. It also describes the chapters and objectives, including internetworking basics, layered models, the OSI model, Ethernet networking, and data encapsulation. Cisco's three-layer model is introduced along with examples of switches, hubs, and cabling in a network. Review questions assess understanding of broadcast domains, collision domains, and simultaneous host transmissions.
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CCNA Chapter1
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- 2. CCNA Course Contents • Prerequisite : Good Knowledge in Computer Networking – Introduction to Internetworking. – TCP/IP Fundamentals. – Subnetting , Variable length Subnetting. – IP Routing. – EIGRP and OSPF Protocols. – Layer 2 Switching and Spanning Tree Protocol (STP). – Virtual LANs (VLANs). – Security and Access Lists. – Network Address Translation (NAT). 2
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- 4. Chapter 1 Objectives •The 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 4
- 5. Internetworking Basics How wouldyou say the PC named Bob communicates with the PC named Sally? 5
- 6. Internetworking Basics Switchescan 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. 6
- 7. Internetworking Basics Here’s alist 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 7
- 8. Internetworking Basics Routers create an internetwork. 8
- 9. Internetworking Basics There aretwo 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
- 10. Internetworking Basics Internetworking devices 10
- 11. Internetworking Basics Switched networkscreating an internetwork 11
- 12. 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. 12
- 13. 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. 13
- 14. The OSI Model The upper layers 14
- 15. The OSI Model The lower layers 15
- 16. The OSI Model The Layer Functions 16
- 17. The OSI Model Connection-OrientedCommunication 17
- 18. The OSI Model Windowing 18
- 19. The OSI Model Network Layer Routing Table used in a router 19
- 20. The OSI Model Routerin an internetwork 20
- 21. The OSI Model Data Link Layer 21
- 22. Binary Addressing Binary to Decimal Memorization Chart 10000000 128 11000000 192 11100000 224 11110000 240 11111000 248 11111100 252 11111110 254 11111111 255 Conversion Example 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 22
- 23. The OSI Model A hub in an network 23
- 24. The OSI Model A Switch in an network 24
- 25. Ethernet Networking • Ethernetis 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. 25
- 26. Ethernet Collision Detection CSMA/CD 26
- 27. Half and FullDuplex Half-duplex Ethernet is defined in the original 802.3 Ethernet; 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 27
- 28. Ethernet Addressing The MAC,or hardware, address is a 48-bit (6-byte) address written in a hexadecimal format. 28
- 29. Ethernet Cabling Ethernet cablingis an important discussion. Three types of Ethernet cables are available: • Straight-through cable • Crossover cable • Rolled cable We will look at each in the following sections. 29
- 30. Straight Through The straight-throughcable is used to connect • Host to switch or hub • Router to switch or hub 30
- 31. Crossover Cable The crossovercable can be used to connect • Switch to switch • Hub to hub • Host to host • Hub to switch • Router direct to host 31
- 32. Rolled Cable 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
- 33. What type ofcable is used? 33
- 34. What type ofcable is used for each connection? 34
- 35. Data Encapsulation Whena 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= Protocol DataUnit FCS= Frame Check Sequence 36
- 37. Port Numbers The Transportlayer uses port numbers to define both the virtual circuit and the upper-layer process. 37
- 38. Cisco’s Three-Layer Model Thefollowing are the three layers and their typical functions: • The core layer: backbone • The distribution layer: routing • The access layer: switching 38
- 39. Review Question Hub Hub How many broadcast domains are shown? 39
- 40. Review Question Switch Switch Hub Hub Hub Hub Hub Hub How many collision domains are shown? 40
- 41. Which of thehosts can transmit simultaneously without causing collisions? Switch Hub A B C D E F How many collision and broadcast domains are show? 41
- 42. Written Labs andReview Questions – Open your books and go through all the written labs and the review questions. – Review the answers in class. 42