Sybex CCNA 640-802 Chapter 1: Internetworking Instructor & Todd Lammle
Chapter 1 Objectives
• The CCNA Topics Covered in this chapter include:
– Internetworking basics– Network segmentation– How bridges, switches, and
routers are used to physically and logically segment a network
– How routers are employed to create an internetwork
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Internetworking Basics
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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.
Internetworking Basics
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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
Internetworking Basics
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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
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.
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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.
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24
Which of the hosts can transmit simultaneously without causing
collisions?
HubSwitch
How many collision and broadcast domains are show?
A FEDB C