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Exploring the FunctionsExploring the Functions of Networkingof Networking

What Is a Network?

ICND1 volume 1


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Common Physical Components of a NetworkCommon Physical Components of a Network


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Interpreting a Network DiagramInterpreting a Network Diagram


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ResourceResource--Sharing FunctionsSharing Functions andand BenefitsBenefits

Data and applications

Resources

Network storage

Backup devices


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Impact of User Applications on the NetworkImpact of User Applications on the Network

Impact of User Applications on the

Network

Batch applications

FTP, TFTP, inventory updates No direct human interaction

Bandwidth important, but not critical

Interactive applications

Inventory inquiries, database updates.

Human-to-machine interaction.

Because a human is waiting for a

response, response time is important

but not critical, unless the wait

becomes excessive.

Real-time applications

VoIP, video

Human-to-human interaction

End-to-end latency critical

Impact of User Applications on the Network


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Understanding theUnderstanding the HostHost--toto--HostHostCommunicationsCommunications ModelModel

Older model

Proprietary

Application and combinations software

controlled by one

vendor Standards-based model

Multivendor software

Layered approach

Understanding Host-to-Host Communications


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The OSI Reference ModelThe OSI Reference Model

Reduces complexity

Standardizes interfaces Facilitates modular engineering

Ensures interoperable Technology

Accelerates evolution

Simplifies teaching and learning

Why a Layered Network Model?


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Layer 1:The Physical LayerLayer 1:The Physical LayerThe Seven Layers of the OSI Model


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Layer 2:The Data Link LayerLayer 2:The Data Link Layer


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Layer 3:The Network LayerLayer 3:The Network Layer


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Layer 4:TheTransport LayerLayer 4:TheTransport Layer


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Layer 5:The Session LayerLayer 5:The Session Layer


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Layer 6:The Presentation LayerLayer 6:The Presentation LayerThe Seven Layers of the OSI Model (Cont.)


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Layer 7:The Application LayerLayer 7:The Application Layer

The Seven Layers of the OSI Model (Cont.)


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Encapsulation and DeEncapsulation and De--EncapsulationEncapsulation

Data Encapsulation


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Encapsulation and DeEncapsulation and De--EncapsulationEncapsulation

Data De-Encapsulation


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PeerPeer--toto--Peer CommunicationPeer Communication

Peer-to-Peer Communication


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TCP/IP SuiteTCP/IP Suite

Defines four layers

Uses different names for Layers 1 through 3

Combines Layers 5 through 7 into single

application layer

TCP/IP Stack


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TCP/IP Stack vs. the OSI ModelTCP/IP Stack vs. the OSI Model


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Understanding the TCP/IPUnderstanding the TCP/IP

Internet LayerInternet LayerIP Address Format: Dotted Decimal Notation

The binary-to-decimal and decimal-to binary conversion will be

detailed later in this course.


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IP Address Classes:The FirstIP Address Classes:The First

OctetOctet


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IP Address RangesIP Address Ranges

*127 (01111111) is a Class A address reserved for loopback testing

and cannot be assigned to a network.

IP Address Ranges


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Dynamic Host ConfigurationDynamic Host ConfigurationProtocol (DHCP)Protocol (DHCP)

DHCP


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Understanding EthernetUnderstanding Ethernet

Local Area Network


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Ethernet Frame AddressingEthernet Frame Addressing

Communicating Within the LAN


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Ethernet LAN SegmentsEthernet LAN Segments

Signals degrade with transmission distance.

Each Ethernet type has a maximum segment length

LAN Segment Limitations


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Extending a LAN SegmentExtending a LAN Segment

Shares bandwidth

Extends cable distances

Repeats or amplifies signal

Extending LAN Segments


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CollisionsCollisions


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Multiple Collision DomainsMultiple Collision Domains

Multiple Collision Domains


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Typical Causes of Network CongestionTypical Causes of Network Congestion

Network Congestion


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BridgesBridgesEarly Solutions to NetworkEarly Solutions to NetworkCongestionCongestion

Bridges

Operate at Layer 2 of the OSI model

Forward, filter, or flood frames

Have few ports

Are slow


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Switches vs. BridgesSwitches vs. Bridges


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How Switches Segment the EthernetHow Switches Segment the Ethernet

NetworkNetwork

Switches Supersede Bridges

Operate at Layer 2 of the OSI model

Forward, filter, or flood frames

Have many ports

Are fast


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Switching in ActionSwitching in Action


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LANs Using SwitchedTechnologyLANs Using SwitchedTechnology

Users grouped by physical location

More switches added to networks

Switches connected by high-speed links

LANsToday


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VLAN OverviewVLAN Overview

Segmentation

Flexibility

Security

VLAN Overview

VLAN = Broadcast Domain = Logical Network (Subnet)


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Cisco IOS Software Features andCisco IOS Software Features and

FunctionsFunctions

Cisco IOS Software

Features to carry the chosen network protocols and functions Connectivity for high-speed traffic between devices

Security to control access and prohibit unauthorized network use

Scalability to add interfaces and capability as needed for network Growth

Reliability to ensure dependable access to networked resources


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Cisco IOS Software FeaturesCisco IOS Software Features

and Functionsand Functions

An Overview of Cisco Device Startup


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External Configuration SourcesExternal Configuration Sources

Configurations can come from many sources.

Configurations will act in device memory.

- Personal computer (PC) or equivalent with communications softwareconfigured with the following settings:

Speed: 9600 b/s

Data bits: 8

Parity: None

Stop bit: 1

Flow control: None


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Cisco IOS CommandCisco IOS Command--Line InterfaceLine InterfaceFunctionsFunctions

CLI is used to enter commands.

Operations vary on different

internetworking devices. Users type or paste entries in the console

command modes.

Command modes have distinctive

prompts.

Enter key instructs device to parse and

execute the command.Two primary EXEC modes are user mode

and privileged mode.

Cisco IOS User Interface Functions


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Entering the EXEC ModesEntering the EXEC Modes

There are two main EXEC modes for entering commands.

Cisco IOS Software EXEC Mode (User)


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Entering the Privilege ModesEntering the Privilege Modes

Cisco IOS Software EXEC Mode

(Privileged)


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Keyboard Help in the CLIKeyboard Help in the CLI

Switch Command-Line Help Facilities


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ContextContext--Sensitive HelpSensitive Help


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ContextContext--Sensitive Help (Cont.)Sensitive Help (Cont.)


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Enhanced Editing CommandsEnhanced Editing Commands


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Viewing the ConfigurationViewing the Configuration


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show runningshow running--configconfig and showand show

startupconfigstartupconfig CommandsCommands

Displays the current and saved configuration


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Logging In to the SwitchLogging In to the Switch

Logging In to the Switch and Entering the Privileged EXECMode


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Configuring a Switch from theConfiguring a Switch from the

Command LineCommand Line

Configuration modes: Global configuration mode

SwitchX#configure terminalSwitchX(config)#

Interface configuration mode

SwitchX(config)#interface fa0/1

SwitchX(config-if)#

Configuring the Switch


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Configuring Switch IdentificationConfiguring Switch Identification

Sets the local identity for the switch


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Configuring the Switch IPConfiguring the Switch IP

AddressAddress

SwitchX(config)#interface vlan 1SwitchX(config-if)#ip address {ip address} {mask}

Example:

SwitchX(config)#interface vlan 1SwitchX(config-if)#ip address 10.5.5.11 255.255.255.0

SwitchX(config-if)#no shutdown

Note: It is necessary to use the no shutdown command to maketheinterface operational.


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Configuring the Switch DefaultConfiguring the Switch Default

GatewayGateway

SwitchX(config)#ip default-gateway {ip address}

SwitchX(config)#ip default-gateway 172.20.137.1

Example:


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Saving ConfigurationsSaving Configurations

SwitchX

SwitchX copy running-config startup-configDestination filename [startup-config]?

Building configurationSwitchX

Copies the current configuration to NVRAM


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Showing the Switch Initial StartupShowing the Switch Initial Startup

StatusStatus

Showing Switch Initial Startup Status

SwitchX#show version

Displays the configuration of the system hardware, software version, names and

sources of configuration files, and boot images

SwitchX#show running-config

SwitchX#show interfaces

Displays the current active configuration file of the switch

Displays statistics for all interfaces configured on the

switch


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Switch show version CommandSwitch show version Command


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Switch show interfaces CommandSwitch show interfaces Command


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MAC AddressTable ManagementMAC AddressTable Management

Catalyst 2960 Series

Managing the MAC AddressTable


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Understanding Switch SecurityUnderstanding Switch Security

Configuring a Switch Password


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Configuring the Login BannerConfiguring the Login Banner

SwitchX# banner login " Access for authorized users only. Please enter your

username and password. "

Defines and enables a customized banner to be displayed before

the username and password login prompts.

Configuring the Login Banner


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Telnet vs. SSH AccessTelnet vs. SSH Access

Telnet

Most common access method

Insecure

SSH-encrypted


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Port Security ConfigurationPort Security Configuration

Cisco Catalyst 2960 Series

Configuring Port Security


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Verifying Port SecurityVerifying Port Security

on the Catalyst 2960 Serieson the Catalyst 2960 Series


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Verifying Port SecurityVerifying Port Security

on the Catalyst 2960 Series (Cont.)on the Catalyst 2960 Series (Cont.)


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