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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Routers create an internetwork.

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

Internetworking Basics

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Internetworking devices

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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The OSI Model

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The upper layers

The OSI Model

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The lower layers

The OSI Model

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The Layer Functions

The OSI Model

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Connection-Oriented Communication

The OSI Model

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Flow Control

The OSI Model

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Windowing

OSI Model The Transport layer

Reliable delivery

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The OSI Model

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Network LayerRouting Table used in a router

The OSI Model

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Router in an internetwork

Data Link Layer

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The OSI Model

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A Switch in an network

The OSI Model

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A hub in an network

Review Question

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Hub Hub

How many broadcast domains are shown?

Review Question

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Hub HubHub HubHub Hub

Switch Switch

How many collision domains are shown?

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Which of the hosts can transmit simultaneously without causing

collisions?

HubSwitch

How many collision and broadcast domains are show?

A FEDB C

Written Labs and Review Questions

– Open your books and go through all the written labs and the review questions.

– Review the answers in class.

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