Ccna routing and_switching_chapter-1-2-3_mme

© 2008 Cisco Systems, Inc. All rights reserved. Cisco ConfidentialPresentation_ID 1
Chapter 1:Exploring the Network
Introduction to Networks
Chapter 2:Configuring a Network OS
Chapter 3:Network Protocols and Communications
Mohammad Mamun Elahi
Assistant Professor, Department of CSE
Instructor, UIU Cisco Networking Academy

Presentation_ID 2© 2008 Cisco Systems, Inc. All rights reserved. Cisco Confidential
Providing Resources in a Network
Networks of Many Sizes

Clients and Servers

Peer-to-Peer

LANs, WANs, and Internets
Components of a Network
There are three categories of network components:
 Devices
 Media
 Services

Network Media

Network Representations

Topology Diagrams

LANs and WANs
Types of Networks
The two most common types of network infrastructures are:
 Local Area Network (LAN)
 Wide Area Network (WAN).
Other types of networks include:
 Metropolitan Area Network (MAN)
 Wireless LAN (WLAN)
 Storage Area Network (SAN)

LANs and WANs
Local Area Networks (LAN)

LANs and WANs
Wide Area Networks (WAN)

The Internet

The Internet
Intranet and Extranet

Internet Access Technologies

Connecting to the Internet
Connecting Remote Users to the Internet

Connecting to the Internet
Connecting Businesses to the Internet

Converged Networks
The Converging Network

Reliable Network
Supporting Network Architecture
As networks evolve, we are discovering that there are four
basic characteristics that the underlying architectures need to
address in order to meet user expectations:
 Fault Tolerance
 Scalability
 Quality of Service (QoS)
 Security

Reliable Network
Fault Tolerance in Circuit Switched Network

Reliable Network
Packet-Switched Networks

Reliable Network
Scalable Networks

Reliable Network
Providing (QoS)
Examples of priority decisions for an organization might
include:
 Time-sensitive communication - increase priority for services
like telephony or video distribution.
 Non time-sensitive communication - decrease priority for web
page retrieval or email.
 High importance to organization - increase priority for
production control or business transaction data.
 Undesirable communication - decrease priority or block
unwanted activity, like peer-to-peer file sharing or live
entertainment

Reliable Network
Providing Network Security

Network Trends
Data Centers
A data center is a facility used to house computer systems and
associated components including:
 Redundant data communications connections
 High-speed virtual servers (sometimes referred to as server
farms or server clusters)
 Redundant storage systems (typically uses SAN technology)
 Redundant or backup power supplies
 Environmental controls (e.g., air conditioning, fire
suppression)
 Security devices

Networking Technologies for the Home
Technology Trends in the Home

Networking Technologies for the Home
Wireless Broadband

Future of Networking
Network Security

Network Security
Security Threats
The most common external threats to networks include:
 Viruses, worms, and Trojan horses
 Spyware and adware
 Zero-day attacks, also called zero-hour attacks
 Hacker attacks
 Denial of service attacks
 Data interception and theft
 Identity theft

Network Security
Security Solutions
Network security components often include:
 Antivirus and antispyware
 Firewall filtering
 Dedicated firewall systems
 Access control lists (ACL)
 Intrusion prevention systems (IPS)
 Virtual Private Networks (VPNs)

Chapter 2
2.1 IOS Bootcamp
2.2 Getting Basic
2.3 Address Schemes
2.4 Summary

Cisco IOS
Operating Systems
All networking equipment dependent on operating systems
 End users (PCs, laptops, smart phones, tablets)
 Switches
 Routers
 Wireless access points
 Firewalls
Cisco Internetwork Operating System (IOS)
 Collection of network operating systems used on Cisco devices

Cisco IOS
Operating Systems

Cisco IOS
Location of the Cisco IOS
IOS stored in Flash
 Non-volatile storage – not lost when power is lost
 Can be changed or overwritten as needed
 Can be used to store multiple versions of IOS
 IOS copied from flash to volatile RAM
 Quantity of flash and RAM memory determines IOS that can be used

Cisco IOS
IOS Functions
Major functions performed or enabled by Cisco routers and
switches include:

Accessing a Cisco IOS Device
Console Access Method
Most common methods to access the Command Line Interface
 Console
 Telnet or SSH
 AUX port

Console Access Method
Console port
 Device is accessible even if no networking services have been
configured (out-of-band)
 Need a special console cable
 Allows configuration commands to be entered
 Should be configured with passwords to prevent unauthorized access
 Device should be located in a secure room so console port can not
be easily accessed

Telnet, SSH, and AUX Access Methods
Telnet
 Method for remotely accessing the CLI over a network
 Require active networking services and one active interface that is
configured
Secure Shell (SSH)
 Remote login similar to Telnet but utilizes more security
 Stronger password authentication
 Uses encryption when transporting data
Aux Port
 Out-of-band connection
 Uses telephone line
 Can be used like console port

Terminal Emulation Programs
Software available for
connecting to a networking
device
 PuTTY
 Tera Term
 SecureCRT
 HyperTerminal
 OS X Terminal

Navigating the IOS
Cisco IOS Modes of Operation

Navigating the IOS
Primary Modes

Navigating the IOS
Global Configuration Mode and Submodes

Navigating the IOS
Navigating between IOS Modes

Navigating the IOS
Navigating between IOS Modes (cont.)

The Command Structure
IOS Command Structure

Context Sensitive Help

Command Syntax Check

Hot Keys and Shortcuts
 Tab - Completes the remainder of a partially typed command or
keyword
 Ctrl-R - Redisplays a line
 Ctrl-A – Moves cursor to the beginning of the line
 Ctrl-Z - Exits configuration mode and returns to user EXEC
 Down Arrow - Allows the user to scroll forward through former
commands
 Up Arrow - Allows the user to scroll backward through former
commands
 Ctrl-Shift-6 - Allows the user to interrupt an IOS process such
as ping or traceroute.
 Ctrl-C - Aborts the current command and exits the configuration
mode

IOS Examination Commands

The show version Command

Hostnames
Why the Switch
Let’s focus on
 Creating a two PC network connected via a switch
 Setting a name for the switch
 Limiting access to the device configuration
 Configuring banner messages
 Saving the configuration

Hostnames
Device Names
Some guidelines for naming conventions are that names should:
 Start with a letter
 Contain no spaces
 End with a letter or digit
 Use only letters, digits, and dashes
 Be less than 64 characters in length
Without names, network
devices are difficult to
identify for configuration
purposes.

Hostnames
Hostnames
Hostnames allow
devices to be
identified by
network
administrators
over a network or
the Internet.

Hostnames
Configuring Hostnames

Limiting Access to Device Configurations
Securing Device Access
The passwords introduced here are:
 Enable password - Limits access to the privileged
EXEC mode
 Enable secret - Encrypted, limits access to the
privileged EXEC mode
 Console password - Limits device access using the
console connection
 VTY password - Limits device access over Telnet
Note: In most of the labs in this course, we will be
using simple passwords such as cisco or class.

Securing Privileged EXEC Access
 use the enable secret command, not the
older enable password command
 enable secret provides greater security because
the password is encrypted

Securing User EXEC Access
 Console port must be secured
• reduces the chance of unauthorized personnel physically
plugging a cable into the device and gaining device access
 vty lines allow access to a Cisco device via Telnet
• number of vty lines supported varies with the type of
device and the IOS version

Encrypting Password Display
service password-
encryption
 prevents
passwords from
showing up as
plain text when
viewing the
configuration
 purpose of this
command is to
keep unauthorized
individuals from
viewing passwords
in the configuration
file
 once applied,
removing the
encryption service
does not reverse
the encryption

Banner Messages
 important part of
the legal process in
the event that
someone is
prosecuted for
breaking into a
device
 wording that
implies that a login
is "welcome" or
"invited" is not
appropriate
 often used for legal
notification
because it is
displayed to all
connected
terminals

Saving Configurations
Configuration Files
 Switch# reload
System configuration has
been modified. Save?
[yes/no]: n
Proceed with reload?
[confirm]
 Startup configuration is
removed by using
the erase startup-config
Switch# erase startup-config
 On a switch you must
also issue the delete
vlan.dat
Switch# delete vlan.dat
Delete filename [vlan.dat]?
Delete flash:vlan.dat?
[confirm]

Saving Configurations
Capturing Text

Ports and Addresses
IP Addressing in the Large
 Each end device on a
network must be
configured with an IP
address
 Structure of an IPv4
address is called dotted
decimal
 IP address displayed in
decimal notation, with
four decimal numbers
between 0 and 255
 With the IP address, a
subnet mask is also
necessary
 IP addresses can be
assigned to both
physical ports and virtual
interfaces

Ports and Addresses
Interfaces and Ports
 Network communications depend on end user device interfaces,
networking device interfaces, and the cables that connect them
 Types of network media include twisted-pair copper cables, fiber-
optic cables, coaxial cables, or wireless
 Different types of network media have different features and benefits
 Ethernet is the most common local area network (LAN) technology
 Ethernet ports are found on end user devices, switch devices, and
other networking devices
 Cisco IOS switches have physical ports for devices to connect to, but
also have one or more switch virtual interfaces (SVIs - no physical
hardware on the device associated with it; created in software)
 SVI provides a means to remotely manage a switch over a network

Addressing Devices
Configuring a Switch Virtual Interface
 IP address - together with subnet mask, uniquely identifies end device
on internetwork
 Subnet mask - determines which part of a larger network is used by
an IP address
 interface VLAN 1 - interface configuration mode
 ip address 192.168.10.2 255.255.255.0 - configures the IP address
and subnet mask for the switch
 no shutdown - administratively enables the interface
 Switch still needs to have physical ports configured and VTY lines to
enable remote management

Addressing Devices
Manual IP Address Configuration for End Devices

Addressing Devices
Automatic IP Address Configuration for End Devices

Addressing Devices
IP Address Conflicts

Verifying Connectivity
Test the Loopback Address on an End Device

Testing the Interface Assignment

Testing End-to-End Connectivity

Chapter 3
3.1 Rules of Communication
3.2 Network Protocols and Standards
3.3 Moving Data in the Network
3.4 Summary

The Rules
What is Communication?

The Rules
Message Formatting and Encapsulation
Example: Personal letter contains the following elements:
 An identifier of the recipient
 A salutation or greeting
 The message content
 A closing phrase
 An identifier of the sender

The Rules
Message Delivery Options

Protocols
Rules that Govern Communications

Protocols
Network Protocols
 How the message is formatted or structured
 The process by which networking devices share information
about pathways with other networks
 How and when error and system messages are passed
between devices
 The setup and termination of data transfer sessions

Protocols
Interaction of Protocols
 Application Protocol – Hypertext Transfer Protocol (HTTP)
 Transport Protocol – Transmission Control Protocol (TCP)
 Internet Protocol – Internet Protocol (IP)
 Network Access Protocols – Data Link & Physical layers

Protocol Suites
Protocol Suites and Industry Standards

Protocol Suites
TCP/IP Protocol Suite and Communication

Reference Models
The OSI Reference Model

Reference Models
The TCP/IP Reference Model

Reference Models
Comparing the OSI and TCP/IP Models

Data Encapsulation
Communicating the Messages
 Segmenting message benefits
Different conversations can be interleaved
Increased reliability of network communications
 Segmenting message disadvantage
Increased level of complexity

Data Encapsulation
Protocol Data Units (PDUs)
 Data
 Segment
 Packet
 Frame
 Bits

Data Encapsulation
Encapsulation

Data Encapsulation
De-encapsulation

Moving Data in the Network
Accessing Local Resources

Network Addresses & Data Link addresses
 Network Address
Source IP address
Destination IP address
 Data Link Address
Source data link address
Destination data link address

Communicating with Device / Same Network

MAC and IP Addresses
PC1
192.168.1.110
AA-AA-AA-AA-AA-AA
PC2
192.168.1.111
BB-BB-BB-BB-BB-BB
FTP Server
192.168.1.9
CC-CC-CC-CC-CC-CC
R1
192.168.1.1
11-11-11-11-11-11
ARP
Request
S1 R1

Accessing Remote Resources
Default Gateway
PC 1
192.168.1.110
AA-AA-AA-AA-AA-AA
PC 2
192.168.1.111
BB-BB-BB-BB-BB-BB
FTP Server
192.168.1.9
CC-CC-CC-CC-CC-CC
R1
192.168.1.1
11-11-11-11-11-11
R2
172.16.1.99
22-22-22-22-22-22
Web Server
172.16.1.99
AB-CD-EF-12-34-56

Communicating Device / Remote Network

Using Wireshark to View Network Traffic

Ccna routing and_switching_chapter-1-2-3_mme

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