Chapter 1 – Introduction to Networking

Einführung

CISCO 1

The Computer is the Network.

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Agenda

• Basics

1. What is networking?

2. Physical connections

3. Installing Network Interface Cards (NICs)

4. Using Ping

• Networks

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Outline

1. What is networking?

2. Physical connections

3. Installing Network Interface Cards (NICs)

4. Using Ping

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The role of an IT (Information Technology) Professional

• Networks are no longer a “luxury”, but a required resource necessary for an organization to conduct business.

• In most organizations, networks must be operational 24x7, for anything from mission critical applications to accessing email and information from off-campus.

• 9 out of 10 jobs in the IT (Information Technology) industry are in non-IT companies (ITAA).

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Computer Technician

• Desktop and Network support– Responsible for setting up and maintaining the users’ computers.– Helping users with network access.– Direct user support.– Adding hardware and software– Setting up accounts, email, and access to servers– Security– Troubleshooting– Helping users

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Network Technician

• Connecting the computers to the network.

• Install, manage, troubleshoot network infrastructure:– Routers, Switches, Cables, Wireless

Access Points

• Issues: – Security– Quality of Service– Video On Demand– IP Telephony or Voice over IP

• Wireless network access.

• Configure the routers and switches.– Basic configurations– Security– Traffic flow

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System Administrator

• Maintaining the “file servers”, the computers that store the software and data used by everyone.– Email, Web, DNS– Security Systems

• Setting up usernames and passwords for controlling access to the network.

• Setting up and maintaining the servers that control Email.

• Keep the computers secure from viruses and hackers.

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Understanding what is happening…

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What is networking?

• Communication!• An interconnection of

computers and other devices:– Printers– Servers (computers)– Scanners– Network Devices

• Hubs• Switches• Routers• Firewall• Modem• Wired and Wireless

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Most successful networking applications?

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Outline

1. What is networking?

2. Physical connections

3. Installing Network Interface Cards (NICs)

4. Using Ping

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Requirements for Internet connection

• Physical connection from a computer (PC) to a network– Telephone Modem (Analog) – Network Interface Card (NIC)

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Requirements for Internet connection

• Logical connection uses standards called protocols (rules for how information is transmitted): (More LATER!)– Ethernet– TCP/IP, a “suite of protocols”

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Requirements for Internet connection

• Applications that interprets the data and displays the information in an understandable form:– Web browser – File Transfer Protocol (FTP)

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Four things you need to connect to other computers over the Internet and most networks

1. IP Address

2. Subnet Mask

3. Default Gateway Address

4. DNS (Domain Name Server) Address

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Outline

1. What is networking?

2. Physical connections

3. Installing Network Interface Cards (NICs)

4. Using Ping

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Network interface cards (NIC)

A NIC is used to connect a device (computer) to a LAN (Local Area Network).

The LAN is usually connected to a ISP (Internet Service Provider)

When selecting a NIC, consider the following factors:

• Protocols – Ethernet, Token Ring (becoming obsolete), wireless protocols: 802.11a, b, or g

• Types of media – Twisted-pair, coaxial (older technology), wireless, or fiber-optic

• More LATER!

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• A modem, or modulator-demodulator, is a device that provides the computer with connectivity to a telephone line.

• Converts signals from analog to digital, and digital to analog.• Depending upon your “Internet connection”, you may have just a

NIC, just a modem or both.

NIC and modem installation

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Overview of high-speed and dial-up connectivity

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Outline

1. What is networking?

2. Physical connections

3. Basic computer components

4. Installing Network Interface Cards (NICs)

5. Using Ping

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TCP/IP description and configuration

• Transmission Control Protocol/Internet Protocol (TCP/IP) is a set of protocols or rules developed to allow cooperating computers to share resources across a network.

• Includes a “unique” (well, not always) address assigned to your computer

• Much more LATER!

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Verify IP Configuration: Win XP, NT, 2000

• ipconfig

• ipconfig /all

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2

3

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Verify IP Configuration: Win 9x

1 2

3 4

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TCP/IP description and configuration

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Verify IP Configuration: MAC OS

• From the Apple menu, open your Control Panel, and select the TCP/IP option. (older MacOS versions use the MacTCP control panel.)

• Click on the "Info" button in the TCP/IP configuration dialog.

• The configuration dialog shown to the right will be displayed. Look at the address listed next to the line "This Macintosh"

• In this example, the IP address is 192.168.10.30

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Verify IP Configuration: MAC OS X

• Select the Apple Menu, choose the System Preferences option, and the Network control panel.

• Select the TCP/IP tab.

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Verify IP Configuration: Linux/Unix

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Testing connectivity with ping

• The ping command works by sending multiple IP packets to a specified destination. Each packet sent is a request for a reply.

• The ping command is used to test the NIC transmit/receive function, the TCP/IP configuration, and network connectivity.

Loopback Address

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Agenda

• Basics

1. What is networking?

2. Physical connections

3. Installing Network Interface Cards (NICs)

4. Using Ping

• Networks

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Time Sharing

• Early networks utilized time sharing

• Computer OS managed individual users, giving each one a slice of time.

• Computer was fast enough so it looked as if each user had exclusive access to the computer.

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Computer to Computer Communications

• Prior to TCP/IP and the Internet, computer to computer communications was very difficult.

• Difficult to share data between computers.

• Different hardware

• Different operating systems

• Different protocols

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Circuits

Dedicated:= für eine Tätigkeit zugeordnet

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Circuit Switching vs Packet Switching

Circuit Switched Networks (PSTN – Public Switched Telephone Network, ISDN)

• A type of communications where a channel or circuit is established for the duration of the call.

• That circuit is dedicated to the two end nodes using it.

• 1950’s/60’s the networks were analog, circuit switched networks.

• Telephony companies invested millions/billions of dollars in equipment over tens of years, for that investment to be paid off over many years.

• Its about guaranteed levels of service

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Packet Switching

Packet Switched Networks (Frame Relay, ATM)

• Packets (messages or fragments of messages) are individually routed between nodes over data links which might be shared by many other nodes.

• Packets between the same two nodes may take different routes.

• Link fails or becomes unavailable, other links may be used.

• More efficient use of inter-network links.

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Circuit Switch and Packet Switched

• Although the network itself may be a circuit switched or packet switched connection, that circuit could be used for a packet switched traffic (IP packets).

• This will become more clear later.

Chapter 1 – Introduction to Networking

Einführung

CISCO 1

The Computer is the Network.

Danke !!

http://www.netzmafia.de/skripten/netze/