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Ccna ch01
- 1. © Wiley Inc. 2006. All Rights Reserved. CCNA: Cisco Certified Network Associate Study Guide CHAPTER 1: Internetworking
- 2. © Wiley Inc. 2006. All Rights Reserved. The CCNA exam topics covered in this chapter include the following: Technology •Describe network communications using layered models •Compare and contrast key characteristics of LAN environments •Describe the components of network devices •Evaluate rules for packet control
- 3. © Wiley Inc. 2006. All Rights Reserved. The Basic Network The basic network allows devices to share information The term “Computer Language” refers to Binary code (0’s or 1’s)
- 4. © Wiley Inc. 2006. All Rights Reserved. The Basic Internetwork A router creates an internetwork
- 5. © Wiley Inc. 2006. All Rights Reserved. Routing Protocols When you have more then one router, a routing protocol is used to share network information between the routers.
- 6. © Wiley Inc. 2006. All Rights Reserved. Internetworking Basics Possible causes of LAN traffic congestion: • Too many hosts in the broadcast domain • Broadcast storms • Multicasting • Low Bandwidth
- 7. © Wiley Inc. 2006. All Rights Reserved. Internetworking Basics Advantages of using routers in your network: • Routers don’t forward broadcasts by default. • Routers can filter the network based on layer-3 (Network layer) information (i.e., IP address).
- 8. © Wiley Inc. 2006. All Rights Reserved. Internetworking Basics
- 9. © Wiley Inc. 2006. All Rights Reserved. Internetworking Models • The OSI Reference Model • The Layered Approach • Advantages of OSI layered model – Allows multiple-vendor development through standardization of network components – Allows various types of network hardware and software to communicate. – Prevents changes in one layer from affecting other layers, so it does not hamper development.
- 10. © Wiley Inc. 2006. All Rights Reserved. The OSI Reference Model OSI Reference Model’s Seven Layers – Application Layer – Presentation Layer – Session Layer – Transport Layer – Network Layer – Data Ling Layer – Physical Layer
- 11. © Wiley Inc. 2006. All Rights Reserved. The OSI Reference Model • Network devises that operate at all seven layers: – Network Management stations (NMS) – Web and Application servers – Gateways (not default gateways) – Network hosts
- 12. © Wiley Inc. 2006. All Rights Reserved. The OSI Reference Model The Lower Layers •Provides reliable or unreliable delivery •Performs error correction before retransmit •Provides logical addressing, which routers use for path determination •Combines packets into bytes and bytes into frames •Provides access to media using MAC address •Performs error detection not correction •Moves bits between devices •Specifies voltage, wire speed, and pin-out cables
- 13. © Wiley Inc. 2006. All Rights Reserved. The OSI Reference Model The Transport Layer • Flow Control • Connection-Oriented Communication • Acknowledgements
- 14. © Wiley Inc. 2006. All Rights Reserved. The OSI Reference Model
- 15. © Wiley Inc. 2006. All Rights Reserved. The OSI Reference Model The Transport Layer (Windowing)
- 16. © Wiley Inc. 2006. All Rights Reserved. The OSI Reference Model The Network Layer
- 17. © Wiley Inc. 2006. All Rights Reserved. The OSI Reference Model The Network Layer Each router interface is broadcast domain. Routers break up broadcast domains by default and provide WAN services
- 18. © Wiley Inc. 2006. All Rights Reserved. The OSI Reference Model The IEEE Data Link Layer has two sublayers: • Media Access Control (MAC) 802.3 •Logical Link Control (LLC) 802.2
- 19. © Wiley Inc. 2006. All Rights Reserved. Switching (LAN Segmentation) Each segment has its own collision domain. All segments are in the same broadcast domain.
- 20. © Wiley Inc. 2006. All Rights Reserved. Hubs •All devices in the same collision domain •All devices in the same broadcast domain •Devices share the same bandwidth
- 21. © Wiley Inc. 2006. All Rights Reserved. The OSI Reference Model The Physical Layer •Sends and receives bits; 1’s & 0’s •Specify electrical, mechanical, procedural, and functional requirements •DTE/DCE interfaces identified •Hubs (Multi-port repeaters)
- 22. © Wiley Inc. 2006. All Rights Reserved. Ethernet Networking • A connection media access method that allows all hosts on a network to share the same bandwidth (Uses Data Link & Physical Layer specifications) • CSMA/CD • Half Duplex • Full Duplex
- 23. © Wiley Inc. 2006. All Rights Reserved. Ethernet at the Data Link Layer • Ethernet addressing = Hardware or MAC • Framing – Types of Ethernet frames: • Ethernet II • IEEE 802.3 • IEEE 802.2 • SNAP Ethernet Networking
- 24. © Wiley Inc. 2006. All Rights Reserved. Ethernet Frames
- 25. © Wiley Inc. 2006. All Rights Reserved. Ethernet Networking Ethernet Frames
- 26. © Wiley Inc. 2006. All Rights Reserved. Ethernet Networking Ethernet at the Physical Layer The Expanded IEEE Ethernet 802.3 Standards •100BaseTX •100BaseFX •1000BaseCX •1000BaseT •1000BaseSX •1000BaseLX
- 27. © Wiley Inc. 2006. All Rights Reserved. 802.3 Half duplex (CSMA/CD) Unidirectional data flow Higher potential for collision Hubs connectivity One wire pair Shared collision domain Lower Effective Throughput Hub Full duplex Point-to-point only Attached to dedicated switched port Requires full-duplex support on both ends Collision free Collision detect circuit disabled Two wire pair Duplex Overview
- 28. © Wiley Inc. 2006. All Rights Reserved. Ethernet Cabling Straight-Through Cable
- 29. © Wiley Inc. 2006. All Rights Reserved. Ethernet Cabling Crossover Cable
- 30. © Wiley Inc. 2006. All Rights Reserved. Ethernet Cabling Rolled Cable
- 31. © Wiley Inc. 2006. All Rights Reserved. HyperTerminal
- 32. © Wiley Inc. 2006. All Rights Reserved. HyperTerminal
- 33. © Wiley Inc. 2006. All Rights Reserved. Console HyperTerminal Settings
- 34. © Wiley Inc. 2006. All Rights Reserved. Wireless Networking
- 35. © Wiley Inc. 2006. All Rights Reserved. Wireless Networking Wireless Network Types • Narrowband Wireless LANs • Personal Communication Services (PCS) • Narrowband PCS • Broadband PCS • Satellite • Infrared Wireless LANs • Spread Spectrum Wireless LANs
- 36. © Wiley Inc. 2006. All Rights Reserved. Data Encapsulation
- 37. © Wiley Inc. 2006. All Rights Reserved. Data Encapsulation
- 38. © Wiley Inc. 2006. All Rights Reserved. Port Numbers at the Transport Layer
- 39. © Wiley Inc. 2006. All Rights Reserved. The Cisco Three-Layer Hierarchical Model
- 40. © Wiley Inc. 2006. All Rights Reserved. How many collision domains are shown? Hub Hub How many broadcast domains are shown?
- 41. © Wiley Inc. 2006. All Rights Reserved. How many broadcast domains are shown? Hub HubHub HubHub Hub Switch Switch How many collision domains are shown?
- 42. © Wiley Inc. 2006. All Rights Reserved. Which of the hosts can transmit simultaneously without causing collisions? HubSwitch How many collision and broadcast domains are show? A FEDB C
Editor's Notes
- The reason that networks were even created is so that we can easily share information and files. Before networks, we had to use floppy disks or other type of physical media to share files. Before Local Area Networks (LANs), we used mainframes from IBM, Honeywell, DEC, and others. The first LANs used coax connectivity but distance and amount of hosts that could be on a network were limited. On a basic network, hardware addresses (MAC addresses) are used to communicate between the hosts. Hosts communicate with a language referred to as binary code – which is 0’s and 1’s.
- In an internetwork, hosts still use hardware addresses to communicate between each host on the LAN. However, in an internetwork, hosts use logical addresses (IP addresses) to communicate with hosts on a different LAN (other side of the router). Each connection into a router is a different logical network (broadcast domain).
- Routing protocols are used to tell neighbor routers about networks that they are not directly connected to. The routers place these networks in their routing table (map of the internetwork) Examples of routing protocols are RIP, RIPv2, IGRP, EIGRP and OSPF. EIGRP is a Cisco proprietary routing protocol and is the preferred routing protocol for most networks. You only have Cisco routers in your internetwork, right? Once all the routers have converged (all have the same routing table), then a routed protocol (typically and hopefully just IP) can send packets through the internetwork. In smaller networks, you can create static routes instead of using a routing protocol. However, EIGRP works well in small and large networks, so why go through the hassle of static routes? (except for maybe a default route to the Internet).
- <number> Half-duplex Ethernet is defined in the original 802.3 Ethernet and uses only one wire pair with a digital signal running in both directions on the wire. It also uses the CSMA/CD protocol to help prevent collisions and to permit retransmitting if a collision does occur. If a hub is attached to a switch, it must operate in half-duplex mode because the end stations must be able to detect collisions. Half-duplex Ethernet—typically 10BaseT—is only about 30 to 40 percent efficient as Cisco sees it, because a large 10BaseT network will usually only give you 3- to 4Mbps—at most. 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. This means that with full duplex data transfer, you get a faster data transfer compared to half-duplex. And because the transmitted data is sent on a different set of wires then the received data, no collisions will occur—sweet! Full-Duplex is collision free Half-Duplex is subject to collisions Full-Duplex provides higher throughput than Half-Duplex Ethernet of the same bandwidth Half-Duplex operates in a shared collision domain Full-Duplex operates in a private collision domain
- <number> Two collision domains, two broadcast domains. A router breaks up both collision domains and broadcast domains and a hub breaks up no collision domains.
- <number> One broadcast domain, seven collision domains are shown. By default, switches break up collision domains with each port, but are one broadcast domain by default.
- <number> Only the hosts connected to the switch can transmit simultaneously without causing collisions. Four collision domains are shown, one broadcast domain. By default, switches break up collision domains with each port, but they are only one broadcast domain by default.