Computer Network + Notes

Video 1 Welcome to CompTIA Network+ 2009 Training

Basic Networking FundamentalsTrain Signal, Inc. Ed Liberman

In this video

About Your Instructor and Train Signal Whats Covered in this Course Network+ Certification Objectives


About your Instructor and Train Signal

About Ed Liberman MCT, MCP, MCSA, MCSE, MCDST, MCTS, MCITP, A+, NET+, SERVER+ Has worked in technology for almost 20 years. Have been certified and instructing IT for over 10 years. Volunteer time in my local community as a math tutor for struggling grade school children.

About Train Signal Casual Training Method Scenario-Based Training

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Whats Covered in this Course

Video 2 Basic Networking Fundamentals Objective 2.7 Explain common logical network topologies and their characteristics

Video 3 Network Media Objective 2.1 Objective 2.2 Objective 2.4 Objective 2.6 Objective 2.8 Categorize standard cable types and their properties Identify common connector types Given a scenario, differentiate and implement appropriate wiring standards Categorize LAN technology types and properties Install components of wiring distribution

Video 4 Network Topologies Objective 2.3 Identify common physical network topologies Objective 2.5 Categorize WAN technology types and properties Objective 2.7 Explain common logical network topologies and their characteristics

Video 5 OSI Model Objective 4.1 Explain the function of each layer of the OSI model



Video 6 TCP/IP Objective 1.1 Explain the function of common networking protocols Objective 1.3 Identify the following address formats Objective 1.4 Given a scenario, evaluate the proper use of the following addressing technologies and addressing schemes

Video 7 TCP/IP Protocols Objective 1.1 Explain the function of common networking protocols Objective 1.2 Identify commonly used TCP and UDP default ports

Video 8 Network Devices Objective 3.1 Install, configure and differentiate between common network devices Objective 3.2 Identify the functions of specialized network devices Objective 3.3 Explain the advanced features of a switch

Video 9 Routing Objective 1.5 Identify common IPv4 and IPv6 routing protocols Objective 1.6 Explain the purpose and properties of routing



Video 10 Wireless Networking Objective 1.7 Compare the characteristics of wireless communication standards Objective 3.4 Implement a basic wireless network

Video 11 Networking Command Line Tools Objective 5.1 Given a scenario, select the appropriate command line interface tool and interpret the output to verify functionality

Video 12 Network Performance Optimization Objective 4.5 Explain different methods and rationales for network performance optimization

Video 13 Network Tools Objective 5.3 Given a scenario, utilize the appropriate hardware tools

Video 14 Network Monitoring Objective 4.4 Conduct network monitoring to identify performance and connectivity issues using the following Objective 5.2 Explain the purpose of network scanners

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Video 15 Documentation Objective 4.2 Identify types of configuration management documentation Objective 4.3 Given a scenario, evaluate the network based on configuration management documentation

Video 16 Troubleshooting Objective 4.6 Given a scenario, implement the following network troubleshooting methodology Objective 4.7 Given a scenario, troubleshoot common connectivity issues and select an appropriate solution

Video 17 Network Security Objective Objective Objective Objective Objective Objective 6.1 Explain the function of hardware and software security devices 6.2 Explain common features of a firewall 6.3 Explain the methods of network access security 6.4 Explain methods of user authentication 6.5 Explain issues that affect device security 6.6 Identify common security threats and mitigation techniques


Are you ready to get started?

Lets Go!!!

Video 2 Basic Networking Fundamentals

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In this video

What is a network? What are some of the different types of networks? Client/Server Peer-to-Peer LANs/CANs/MANs/WANs How do we make connections? What is a Protocol? Introduction to addressing Private vs. Public


What is a network?

The definition of a network is simple. A network is created when you have two or more hosts connected together so that they can communicate and share resources. A host can be any device which has a network interface which allows it to connect to other devices on a network. Some examples of resources which can be shared are documents and printers.


What are some of the different types of networks?

Client/Server In a Client/Server network each hosts will act specifically as a server (The provider of resources) OR a client (The receiver of resources).

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Peer-to-Peer In a Peer-to-Peer network every host will act as a client AND a server.



LAN Local Area Network Typically refers to a network contained within a building.



CAN Campus Area Network A network spread between multiple contiguous buildings.

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MAN Metropolitan Area Network A network spread between multiple noncontiguous buildings within the single metropolitan area.



WAN Wide Area Network A network spread over a wide area, typically covering multiple cities and countries.


How do we make connections?

Network hosts communicate with each other by sending bits of information across network media. Network media can be wire or wireless. Examples of wire media are copper and fiber optic. Examples of wireless media are RF and infra-red. We will discuss all the different forms of media in detail later in this course.

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What is a protocol?

The definition of a protocol is a set of rules and procedures for communication. In order for hosts to communicate on a network they must agree to use a common set of rules and procedures or in other words, must use the same network protocol. Some of the common network protocols used today are TCP/IP, IPX/SPX, NetBEUI, and Apple Talk. We will discuss the TCP/IP network protocol in detail later in this course.


Introduction to addressing.

All hosts on a network must be identified with an address on that network. Addressing in computer networks is similar to how addressing works with the postal network or telephone network. The most typical types of addresses used in computer networking are MAC addresses and IP addresses. There are both private and public forms of addressing. Private addressing is used to keep communications safe within the boundaries of a private secure network. Public addressing is used to allow communications with the outside world, most typically known as the Internet. We will discuss addressing in detail later in this course.


In this video we discussed:

What a network is. Different types of networks: Client/Server Peer-to-Peer LANs/CANs/MANs/WANs Network media and protocols. The concept of addressing.

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Video 3 Network Media


In this video

Wired Media Twisted Pair Coaxial Fiber Optic What the heck is the plenum? Common Connectors Wiring Standards LAN Technology Types Wiring Distribution


Wired Media Twisted Pair

CAT 3: 10 Mbps CAT 5: 100 Mbps CAT 5e: 1000 Mbps CAT 6: 1000 Mbps All categories can travel up to 100 meters before suffering from attenuation. UTP: Unshielded Twisted Pair Susceptible to EMI STP: Shielded Twisted Pair Protects against EMI Uses an RJ-45 Connector

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Wired Media - Coaxial

Coaxial cable is made up of 4 layers: Copper Core Inner Insulator Shielding Wire Mesh Outer Insulator Thinnet (RG-58) 10 Mbps 185 Meters Uses a BNC Connector Has been primarily replaced by twisted pair. RG-59 & RG-6 Typically used for cable tv.


Wired Media Fiber Optic

Fiber optic cable uses light pulses instead of electricity to transmit data. Benefits More Secure Not Susceptible to EMI Very Fast Long Distances Drawbacks More Expensive Not as Flexible Uses SC, ST, and LC Connectors


What the heck is the plenum?

An enclosed space used for airflow. Usually thought of as the space above a drop ceiling or below a raised floor. Plenum grade cable should always be used in a plenum space.

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Common Connectors

RJ-45

RJ-11

BNC

SC ST LC

RS-232 Serial Cable

RG-59 or RG-6


Wiring Standards

EIA/TIA - 568A vs. 568B


Wiring Standards

A straight cable has 568A wiring on both ends. A cross-over cable has 568A on one end and 568B on the other. A rollover cable has 568A on one end and the complete reversal of wires on the other. A loopback cable is used to fool the computer interface into thinking it is connected to another device.

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LAN Technology Types Ethernet

Ethernet is the most common form of network communication used in todays local networks. Ethernet is known as the 802.3 standard. Ethernet uses the CSMA/CD access method. CSMA/CD stands for Carrier Sense Multiple Access with Collision Detection.


LAN Technology Types Standard Ethernet

10BaseT 10 Base T

10 How Fast = 10Mbps Base Baseband vs Broadband = Baseband T Type of Cable = Twisted Pair Cable


LAN Technology Types Fast Ethernet

100BaseTX 100BaseFX Both are 100Mbps Both are Baseband TX = Twisted Pair Cable FX = Fiber Optic Cable

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LAN Technology Types Gigabit Ethernet

1000BaseT 1000BaseX Both are 1000Mbps or 1Gbps Both are Baseband T = Twisted Pair Cable X = Fiber Optic Cable


LAN Technology Types 10 Gigabit Ethernet

10GBaseT 10GBaseSR 10GBaseLR 10GBaseER 10GBaseSW 10GBaseLW 10GBaseEW

All are 10Gbps All are Baseband T = Twisted Pair Cable SR,LR,ER = Fiber Optic Cable SW,LW,EW = SONET


Wiring Distribution

Cross Connects Cable which connects you to a backbone or provider. Typically cable found in a wiring closet connected to a patch panel. Patch Panel

MDF Main Distribution Frame IDF Intermediate Distribution Frame

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Wiring Distribution

66 Block and 110 Block

25 Pair and 100 Pair Cable

Demarc The point at which the telephone companys network ends and connects to your wiring. Demarc Extension An extension from where the telephone companys network ends and your network truly begins. Smart Jack The actual termination of a T1 line at your office.



Different types of cabling. What the Plenum is and when to use plenum cable. Common Connectors used in network cabling. Wiring standards for twisted pair cable. Various Ethernet LAN technology types. Wiring distribution hardware.

Video 4 Network Topologies

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In this video

What does topology mean? Physical Network Topologies WAN Technologies What is a VPN? What is a VLAN?


What does topology mean?

A network topology is the layout of the network. The topology can be physical or logical.


Physical Network Topologies - Bus

In the bus topology all of the computers are connected in a straight line. Terminators must be used at each end of a bus segment to prevent signals from bouncing. A single break in the cable would take down the entire network.

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Physical Network Topologies - Star

In the star topology all of the computers are connected through a central connection point (hub). A single break in the cable would only take down communication to one computer. A hub failure would take down the entire network.


Physical Network Topologies - Ring

In the ring topology all of the computers are connected in circular fashion. Data is passed around the ring from computer to computer. A break in the cable would take down the entire network.


Physical Network Topologies - Ring

In the ring topology all of the computers are connected in circular fashion. Data is passed around the ring from computer to computer. A break in the cable would take down the entire network.

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Physical Network Topologies - Mesh

In the mesh topology all of the computers are connected to all other computers. Typically used in a WAN environment. Provides fault tolerance in the event of a connection failure.


Physical Network Topologies - Mesh

In the mesh topology all of the computers are connected to all other computers. Typically used in a WAN environment. Provides fault tolerance in the event of a connection failure.


Physical Network Topologies - Hybrid

Different types of topologies can be used together to form a hybrid topology.

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WAN Technologies

Circuit Switching A physical connection path is established between the source and the destination typically through a series of circuits. Packet Switching Data is broken into packets which then each take a separate independent route to the destination where they are reassembled back into data.


WAN Technologies

POTS Plain Old Telephone Service PSTN Public Switched Telephone Network T1/ E1 A T1 is a digital leased line consisting of 24 64K channels providing a transfer rate up to 1.544 Mbps. An E1 is the European version with 30 channels providing up to 2.048 Mbps. T3/E3 A T3 is basically 28 T1 lines (672 channels) providing a transfer rate up to 44.736 Mbps. An E3 has 512 channels providing up to 34.368 Mbps.


WAN Technologies

ISDN Integrated Services Digital Network BRI: Basic Rate Interface uses 2 64K B-channels to transmit data and 1 16K D-channel to transmit control information. PRI: Primary Rate Interface uses 23 64K Bchannels for data and 1 64K D-channel for control information providing for essentially the same throughput as a T1 line.

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WAN Technologies

SONET/OC-x Synchronous Optical Network SONET is a network technology designed to carry large volumes of traffic over relatively long distances via fiber optic cabling. The data rates of a SONET network are divided into OC-levels (Optical Carrier Levels): OC-1 = 51.84 Mbps OC-3 = 155.52 Mbps OC-12 = 622.08 Mbps OC-24 = 1.244 Gbps OC-48 = 2.488 Gbps OC-192 = 10 Gbps OC-256 = 13.271 Gbps OC-768 = 40 Gbps


WAN Technologies

Frame Relay A WAN where all nodes are connected through a packet switching cloud. You pay a base price for an agreed upon CIR (Committed Information Rate), and then pay additional for only the bandwidth actually used. ATM Asynchronous Transfer Mode Advanced packet switching network using fixed length packets (53 bytes). Provides data rates up to 622 Mbps.


WAN Technologies

MPLS Multiprotocol Label Switching MPLS is a technique, not a service. Known by many different names. Primary concept is the use of labeling.

http://www.networkworld.com/research/2007/040207-mpls-migration-explained.html

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WAN Technologies

DSL Digital Subscriber Line Provides high speed Internet connections using standard copper telephone wires. DSL comes in different flavors: ADSL Asymmetric Digital Subscriber Line allows POTS and data to be transmitted simultaneously. SDSL Symmetric Digital Subscriber Line cannot share data transmission with POTS. VDSL Very High Speed Digital Subscriber Line allows access to the maximum bandwidth available on a standard phone line (13 55 Mbps).


WAN Technologies

Cable Modem Provides high speed Internet connections using a broadband cable connection. Satellite Provides high speed Internet connections using satellite communication. Typically used where DSL and Cable Internet are not available. Wireless Used primarily by mobile users. Provided through WiFi hotspots or through the cellular phone network.


What is a VPN?

VPN stands for Virtual Private Network VPNs allow travelling users to connect to the local network when they are not in the office. Users remotely connect to a VPN server over a standard Internet connection. VPN connections are secured by using tunneling protocols.

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What is a VLAN?

VLAN stands for Virtual LAN (Local Area Network). There are 2 ways of looking at a VLAN: 1. One physical segment divided logically into 2 or more segments. 2. Multiple physical segments acting as a single logical segment. We will discuss VLANs further later in this course.



Network Topologies Bus Star Ring Mesh WAN Technologies VPNs and VLANs

Video 5 OSI Model

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In this video

Review the Definition of a Protocol Explain the Different Layers of the OSI Model


Definition of a Protocol

What is a Protocol? A protocol is a set of rules and procedures used for communication.


Example: USPS Protocol

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Example: Fedex Protocol


Definition of a Protocol

Computers on a network must agree upon a common protocol in order to communicate.

Destination: USPS P.O. Box

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Standards of Communication

In this example: Packaging Addressing Payment Getting the package on the network


What is the OSI Model?

In the 1970s the International Standards Organization (ISO) developed the Open Systems Interconnection (OSI) reference model to define the basic standards for network communication.



In the 1970s the International Standards Organization (ISO) developed the Open Systems Interconnection (OSI) reference model to define the basic standards for network communication.

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The OSI Model is made up of 7 layers. Application Presentation Session Transport Network Data Link Physical



The OSI Model is made up of 7 layers. Application Presentation Session Transport Network Data Link Physical A P S T N D P



The OSI Model is made up of 7 layers. Application Presentation Session Transport Network Data Link Physical All People Seem To Need Data Processing

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The OSI Model is made up of 7 layers. Application Presentation Session Transport Network Data Link Physical All People Seem To Need Data Processing Away Pizza Sausage Throw Not Do Please



Here are some additional sayings: A Priest Saw Two Nuns Doing Pushups All People Should Try New Diet Pepsi Please Do Not Take Sales Peoples Advice Please Do Not Tease Stupid Party Animals

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After watching this video you should be able to:

Explain what a protocol is and how we use it to communicate on a network. Define the 7 layers of the OSI Model and explain its significance within a network.

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Video 6 TCP/IP


In this video

The TCP/IP Protocol Suite Working with IP Addresses Planning an IP Addressing Scheme Working with Binary Numbers Internetworking Classful vs. Classless Interdomain Routing (CIDR) Fundamentals of IPv6


The TCP/IP Protocol Suite

TCP/IP stands for the Transmission Control Protocol/Internet Protocol. It is the basic communication protocol of the Internet. Although it was designed to be an Internet protocol, it can also be used as a communication protocol in a private network. The TCP/IP architecture is based off the 4 layer DARPA model. Each layer of the DARPA model corresponds to one or more of the layers of the 7 layer OSI model. Each of the 4 layers have individual protocols which all work together to form a protocol stack.

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What is the TCP/IP (DARPA) Model?





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Transport Layer Protocols

TCP Transmission Control Protocol One to One Connection-oriented Reliable Communication UDP User Datagram Protocol Connectionless Unreliable Communications


What makes TCP connection-oriented?

Connection-oriented communication means that a connection must be established before data can be exchanged. TCP uses a three-way handshake to establish this connection.

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Three-way Handshake


Three-way Handshake


Three-way Handshake

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Three-way Handshake


Transport Layer Protocols

TCP Transmission Control Protocol One to One Connection-oriented Reliable Communication UDP User Datagram Protocol Connectionless Unreliable Communications


Internet Layer Protocols

IP Internet Protocol Addressing Routing ARP Address Resolution Protocol Resolves an IP address to hardware address

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Internet Layer Protocols

ICMP Internet Control Message Protocol Diagnostic and error reporting IGMP Internet Group Management Protocol Manages IP multicast group membership


Types of TCP/IP Communication

Unicast (One to One) Multicast (One to Many) Broadcast (One to All)


Unicast (One to One)

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Multicast (One to Many)


Broadcast (One to All)


Working with IP Addresses

What is an IP Address? A 32 bit address that is used to uniquely identify a computer on a network. The Network ID portion of the IP Address identifies the network where the computer sits. The Host ID portion of the IP Address uniquely identifies the computer on its network.

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Example: IP Address: 192.168.10.1 Host ID

Network ID



Example: IP Address: Subnet Mask: 192.168.10.1 255.255.255.0 Host ID

Network ID




Network ID

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Network ID




Network ID


Simple Network:

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Planning an IP Addressing Scheme

How to Plan an IP Addressing Scheme How many IP Addresses do you need today? How many IP Addresses will you need in the future? Are you dealing with a pre-existing IP scheme?


Rules for IP Addressing

Each of the 4 numbers in an IP Address is called an octet (8 bits). 192.168.10.101 A bit is a 1 or a 0. Each octet can only have a number from 0 to 255 00000000 = 0 11111111 = 255



The first octet cannot be 127. The 127 range has been reserved for diagnostics. 127.0.0.1 is known as the loopback address. (It is sometimes also referred to as localhost.)

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The Host ID cannot be all 0s or all 255s. All 0s represents the Network ID All 255s is the broadcast address Example: 192.168.10.0 is a Network ID 192.168.10.255 is the broadcast address for the 192.168.10.0 network.


What is Classful IP Addressing?

Originally IP Addresses where divided into different class ranges: A Class: 1 126 255.0.0.0 B Class: 128 191 255.255.0.0 C Class: 192 223 255.255.255.0 D Class: 224 239 Multicast E Class: 240 243 Experimental


What is Classful IP Addressing?

A Class 126 Networks, 16,777,214 Hosts B Class 16,384 Networks, 65,534 Hosts C Class 2,097,152 Networks, 254 Hosts Total of 3,720,314,628 host addresses available

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Private vs. Public IP Addressing

Private IP ranges which have been reserved from Public Internet use: 10.0.0.0 10.255.255.255 172.16.0.0 172.31.255.255 192.168.0.0 192.168.255.255 169.254.0.0 169.254.255.255


Private vs. Public IP Addressing

Hosts assigned private IP Addresses can get to the Internet through a technology called Network Address Translation (NAT) Most of todays companies use private IP Addresses on their private networks.


What is NAT?

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How Computers get IP Addresses

Statically From a DHCP Server Using APIPA


Working with Binary Numbers

What is this number? 3,482 Three Thousand Four Hundred Eighty Two 1,000 3 3x 4x 8x 2x 1,000 100 10 1 100 4 = = = = 3,000 400 80 2 3,482 10 8 1 2


Decimal vs. Binary

Decimal or Base 10: 106 105 104 103 102 101 100 1,000,000 100,000 10,000 1,000 100 10 1 Number Selection: 0 - 9 Binary or Base 2: 212 211 210 29 28 27 26 25 24 23 22 21 20 Number Selection: 0 - 1 4096 2048 1024 512 256 128 64 32 16 8 4 2 1

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Convert Binary to Decimal

128

64

32

16

8

4

2

1

10101010



128 1

64 0

32 1

16 0

8 1

4 0

2 1

1 0



128 1

64 0

32 1

16 0 128 32 8 2 170

8 1

4 0

2 1

1 0

+

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128 1

64 0

32 1

16 0 128 32 8 2 170 =

8 1

4 0

2 1

1 0

+ Binary 10101010

Decimal 170


Convert Decimal to Binary

4096 2048 1024 512 256 128 64 32 16 8 4 2 1 3482



4096 2048 1024 512 256 128 64 32 16 8 4 2 1 1 3482 - 2048 1434

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4096 2048 1024 512 256 128 64 32 16 8 4 2 1 1 1 3482 1434 - 2048 - 1024 1434 410



4096 2048 1024 512 256 128 64 32 16 8 4 2 1 1 1 1 3482 1434 410 - 2048 - 1024 - 256 1434 410 154



4096 2048 1024 512 256 128 64 32 16 8 4 2 1 1 1 1 1 3482 1434 410 154 - 2048 - 1024 - 256 - 128 1434 410 154 26

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4096 2048 1024 512 256 128 64 32 16 8 4 2 1 1 1 1 1 1 3482 1434 410 154 26 - 2048 - 1024 - 256 - 128 - 16 1434 410 154 26 10



4096 2048 1024 512 256 128 64 32 1 1 1 1 1 3482 1434 410 154 26 - 2048 - 1024 - 256 - 128 - 16 1434 410 154 26 10

16 8 4 2 1 1 10 -8 2



4096 2048 1024 512 256 128 64 32 1 1 1 1 1 3482 1434 410 154 26 - 2048 - 1024 - 256 - 128 - 16 1434 410 154 26 10

16 8 4 2 1 1 10 -8 2 1 2 -2 0

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4096 2048 1024 512 256 128 64 32 1 1 1 0 1 1 0 0 3482 1434 410 154 26 - 2048 - 1024 - 256 - 128 - 16 1434 410 154 26 10

16 8 4 2 1 1 0 1 0 10 2 -8 -2 2 0



4096 2048 1024 512 256 128 64 32 1 1 1 0 1 1 0 0 3482 1434 410 154 26 - 2048 - 1024 - 256 - 128 - 16 1434 410 154 26 10

16 8 4 2 1 1 0 1 0 10 2 -8 -2 2 0

Decimal 3482

=

Binary 110110011010


Using the Calculator

Decimal 3482

=

Binary 110110011010

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Binary IP Addresses

Each of the 4 numbers in an IP Address is called an octet (8 bits). A bit is a 1 or a 0. Each octet can only have a number from 0 to 255 192.168.10.101


Binary IP Addresses

128 1

64 1128 64 32 16 8 4 2 + 1 255

32 1

16 1

8 1

4 1

2 1

1 1

Binary 00000000 11111111

= =

Decimal 0 255


Binary IP Addresses

128

64

32

16

8

4

2

1

192.168.10.101

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Binary IP Addresses

128 1

64 1

32 0

16 0

8 0

4 0

2 0

1 0

192.168.10.101 192 = 11000000


Binary IP Addresses

128 1

64 0

32 1

16 0

8 1

4 0

2 0

1 0

192.168.10.101 192 = 11000000 168 = 10101000


Binary IP Addresses

128 0

64 0

32 0

16 0

8 1

4 0

2 1

1 0

192.168.10.101 192 = 11000000 168 = 10101000 10 = 00001010

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Binary IP Addresses

128 0

64 1

32 1

16 0

8 0

4 1

2 0

1 1

192.168.10.101 192 = 11000000 168 = 10101000 10 = 00001010 101 = 01100101


Binary IP Addresses

128

64

32

16

8

4

2

1

192.168.10.101 192 = 11000000 168 = 10101000 10 = 00001010 101 = 01100101 11000000.10101000.00001010.01100101


Binary Subnet Masks

128 1

64 1

32 1

16 1

8 1

4 1

2 1

1 1

255.255.255.0 255 = 11111111 255 = 11111111 255 = 11111111 0 = 00000000 11111111.11111111.11111111.00000000

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Binary IP Address & Subnet Mask

192.168.10.101 255.255.255.0 11000000.10101010.00001010.01100101 11111111.11111111.11111111.00000000


Internetworking

What is a Router? A router is a device that forwards data packets along networks. A router is connected to at least two networks, commonly two LANs or WANs or a LAN and its ISPs network. Routers are located at gateways, the places where two or more networks connect, and are the critical device that keeps data flowing between networks and keeps the networks connected to the Internet. When data is sent between locations on one network or from one network to a second network the data is always seen and directed to the correct location by the router. They accomplish this by using headers and forwarding tables to determine the best path for forwarding the data packets, and the use protocols such as ICMP to communicate with each other and configure the best route between any two hosts.


What is a Router?

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What is a Router?


What is a Default Gateway?

Computers can only communicate directly with other computers on the same network. The only way for a computer to communicate with a computer on a different network is through a router. (Internetworking) The Default Gateway represents the IP Address of a router that a computer uses to communicate outside of its network.


Simple Network:

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What is Subnetting?

Subnetting is the process of taking a large network and dividing it into smaller networks to increase efficiency and manageability.


What is Subnetting?

Example: Network Subnet Mask Subnet 1 Subnet 2 Subnet 3 Subnet Mask - 172.16.0.0 (65534 Hosts) - 255.255.0.0 - 172.16.1.0 (254 Hosts) - 172.16.2.0 (254 Hosts) - 172.16.3.0 (254 Hosts) - 255.255.255.0


Classful vs. Classless Interdomain Routing (CIDR)

Problems with Classful IP Addressing Class A - 16,777,214 Hosts Class B - 65,534 Hosts Class C - 254 Hosts What do you do if you have 2,000 hosts? Pick Class B and waste 63,000+ addresses. Take 8 Class Cs and have cluttered routing table entries.

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Solution:

Classless Interdomain Routing (CIDR) with Variable Length Subnet Masks (VLSM) Decimal Subnet Mask: 255.255.255.0 Binary Subnet Mask: 11111111.11111111.11111111.00000000


Variable Length Subnet Masks

11111111 255 11111110 254 11111100 252 11111000 248 11110000 240 11100000 224 11000000 192 10000000 128 00000000 0


Subnetting with CIDR & VLSM

If we start with 255.255.0.0, but want to divide into smaller networks we need to take bits from the Host ID and move them into the Network ID.

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Formulas

Number of Subnets: 2n n = Number of 1s in the Subnet ID Number of available host addresses: 2n 2 n = Number of 0s in the Host ID Host ID cannot be all 0s or all 1s Example: 11111111.11111111.11111000.00000000 25 = 32 Subnets 211 2 = 2046 Available hosts in each subnet


Simple Network:


Simple Bad Network:

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Why wont my network work?

Client - 192.168.10.101 Server - 192.168.10.201 Router - 192.168.10.200 SM - 255.255.255.248 We need to look at everything in binary: 11000000.10101000.00001010.01100101 11000000.10101000.00001010.11001001 11000000.10101000.00001010.11001000 11111111.11111111.11111111.11111000


How can we fix my network?

With a subnet mask of 255.255.255.248 each network will be broken into blocks of 6 host addresses: Example:11000000.10101000.00001010.00000000 192.168.10.0 11000000.10101000.00001010.00000001 11000000.10101000.00001010.00000010 11000000.10101000.00001010.00000011 11000000.10101000.00001010.00000100 11000000.10101000.00001010.00000101 11000000.10101000.00001010.00000110 11000000.10101000.00001010.00000111 192.168.10.1 192.168.10.2 192.168.10.3 192.168.10.4 192.168.10.5 192.168.10.6 192.168.10.7



With a subnet mask of 255.255.255.248 each network will be broken into blocks of 6 host addresses: Example:11000000.10101000.00001010.00000000 192.168.10.0 11000000.10101000.00001010.00000001 192.168.10.1 11000000.10101000.00001010.00000010 192.168.10.2 11000000.10101000.00001010.00000011 192.168.10.3 11000000.10101000.00001010.00000100 192.168.10.4 11000000.10101000.00001010.00000101 192.168.10.5 11000000.10101000.00001010.00000110 192.168.10.6 11000000.10101000.00001010.00000111 192.168.10.7 Network ID: 192.168.10.0 Host IDs: 192.168.10.1 192.168.10.6 Broadcast ID: 192.168.10.7

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Simple Network (Fixed):

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CIDR Notation

Without CIDR Notation 192.168.10.1 255.255.255.248 With CIDR Notation 192.168.10.1/29


Fundamentals of IPv6

Disadvantages of IPv4 IPv6 Solutions IPv6 Addressing Types of IPv6 Addresses


Disadvantages of IPv4

Not Enough Addresses Cluttered the Internet Routing Tables Difficult to Configure Security is Optional

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IPv6 Solutions

Plenty of Addresses - 3.4 x 1038 Simplified the Internet Routing Tables Easy and Automated Configuration Security is Required


IPv6 Addressing

128 bits long 11111110100000000000000000000000000000000000000000000000000000 000000010111101110000000001111111100000010001110000100011110110001

Displayed in 16 bit hexadecimal blocks FE80:0000:0000:0000:05EE:00FF:0238:47B1 Simplify by suppressing the leading 0s FE80:0:0:0:5EE:FF:238:47B1 Further compress by expressing a single contiguous set of 0 blocks into :: FE80::5EE:FF:238:47B1


Types of IPv6 Addresses

Unicast (One to One) Global Addresses Link-Local Addresses - FE 80 FE80 Unique Local Addresses - FC or FD Multicast (One to Many) Anycast (One to One of Many)

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Describe the TCP/IP Protocol Suite. Explain what an IP address is and decide on an address range appropriate for a network. Convert IP addresses from decimal to binary and from binary to decimal. Explain what a Router is and how we connect networks together. Explain Subnetting and decide when to use Classful vs. Classless Interdomain Routing. Describe the fundamentals of IPv6.

Video 7 TCP/IP Protocols


In this video

FTP TFTP HTTP HTTPS NTP POP3 IMAP4 SMTP

DHCP DNS Telnet SSH SNMP SIP RTP TLS

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FTP

The File Transfer Protocol provides connection oriented file transfer between a client and a server. It was originally used to transfer files between UNIX systems, and is now the most popular file transfer protocol on the Internet. FTP uses TCP port 21 for control and TCP port 20 for data transport.


TFTP

The Trivial File Transfer Protocol provides connectionless file transfer functions. TFTP is a simple and small protocol, which makes it suitable for transferring small amounts of data. It is primarily used for updating devices such as routers and switches. Another common use is transferring the data required to boot a diskless system over the network. TFTP uses UDP port 69.


HTTP

The Hypertext Transfer Protocol was originally designed for transferring World Wide Web documents and has been extended to transfer other types of files as well. Its most common use is transferring web pages between a web browser and a web server. HTTP uses TCP port 80 by default.

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HTTPS

HTTPS is used in exactly the same way as the HTTP protocol. The difference is that HTTPS uses SSL (Secure Sockets Layer) to send data in an encrypted form and to authenticate the server. For example, when you buy something online using a credit card. HTTPS uses TCP port 443 by default.


NTP

The Network Time Protocol is used to provide accurate time synchronization by synchronizing the time of a computer to a reference time source, such as an NTP server, a radio or a satellite receiver. NTP is capable of synchronizing distributed clocks to the millisecond. NTP uses UDP port 123.


POP3

The Post Office Protocol is used to retrieve email. POP3 can be used to access the Inbox folder only. POP3 clients connect to TCP port 110.IMAP4

The Internet Message Access Protocol is also used to retrieve email. Unlike POP3, IMAP4 can be used to access all server-based messaging folders thereby eliminating the need for a local repository. IMAP4 clients connect to TCP port 143.

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SMTP

The Simple Mail Transfer Protocol is used for sending email to and between email servers. SMTP uses TCP port 25.


DHCP

The Dynamic Host Configuration Protocol is used for assigning dynamic IP addresses to devices on a network. DHCP simplifies network administration by keeping track of IP addresses in a database rather than an administrator having to manage and assign them manually. DHCP uses UDP ports 67 & 68.


DNS

The Domain Naming System is a standard name service that allows your computer to register and resolve domain names. DNS uses TCP port 53 for zone transfers and UDP port 53 for lookups.

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Telnet

Telnet is a terminal emulation protocol that allows remote access to a system. Telnet can also refer to software which can be used by a client to remotely connect to and configure operating systems and network devices. Telnet uses TCP port 23.


SSH

Secure Shell can be used to provide similar functionality as Telnet, but is much more secure. Telnet is considered insecure mainly because it sends username and password information in clear text. Therefore, Telnet should be replaced with SSH. SSH employs encryption through certificates and authenticates the server to the client. SSH operates on TCP port 22.


SNMP

The Simple Network Management Protocol is used for network management. It works by having network devices, acting as agents, collecting information and providing that information to SNMP managers. SNMP uses UDP port 161.

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SIP

The Session Initiation Protocol can establish, modify and terminate multimedia sessions or calls. Examples of multimedia sessions include multimedia conferences, distance learning, and Internet telephony.RTP

The Real-Time Transport Protocol provides end-toend network transport functions suitable for applications transmitting real-time data such as audio, video or simulation data, over multicast or unicast network services.


TLS

Transport Layer Security is a protocol for establishing a secure connection between a client and a server. TLS is capable of authenticating both the client and the server creating an encrypted connection between the two. TLS is considered to be a replacement for SSL (Secure Sockets Layer).



Describe what some of the various TCP/IP Protocols are and when they would be used. List the commonly used TCP and UDP ports.

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Video 8 Network Devices


In this video

Modem/NIC Repeater/Hub Bridge/Switch Router Firewall/Proxy Server Wireless Access Point Basic DHCP Server/DNS Server CSU/DSU Load Balancer/Bandwidth Shaper


Modem

Modems are used for dial-up connections over standard analog telephone lines. They can be integrated onto a systems motherboard, an internal expansion card, or an external peripheral device.NIC

Network Interface Cards are used to connect systems to physical network media. They can be integrated onto a systems motherboard or an internal expansion card.

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Repeater

Repeaters are used to help deal with attenuation issues. A repeater will take a signal in on one port and retransmit it out the other.Hub

Hubs are basically multiport repeaters. A hub will take a signal in on one port and forward it on to all other ports.


Bridge

Bridges operate at the Data Link layer of the OSI model. Bridges have simplistic routing tables based on MAC addresses. Bridges are used to create separate collision domains.Switch

Switches are basically multiport bridges. Switches can be used so each computer resides in its own collision domain.


Router

Routers are used to connect networks together. Routers have sophisticated routing tables which can determine the best route to get information from one network to another. Routers function at the Network layer of the OSI model. Routers are used to create separate broadcast domains.

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Different Types of Switches

A Multilayer Switch functions at the Data Link layer of the OSI model just like a regular switch, but also provides additional functionality at higher OSI layers. A Content Switch is an example of a Multilayer Switch which is used to distribute incoming requests to servers that can handle the data in the packets. The Content Switch will inspect the network data and then decide where it should be forwarded to.


Advanced Switch Functionality

Power over Ethernet (PoE) is used to transfer electrical power, along with data, over standard twisted pair cable. The Spanning Tree Algorithm (STA) is used by switches to determine the best route when there is more than one connection to a node. Virtual LANs (VLANs) can be created in order to emulate multiple broadcast domains using switches. Trunking is when a switch presents more than one VLAN configuration over a single connection to another switch or a router. Port Mirroring is used to send a copy of network data to a second (mirrored) connection usually for the purposes of monitoring. Port Authentication is used to restrict access based upon authentication information. Typically used in 802.1x network.


Firewall Firewalls are used to protect private networks from external intrusion. Firewalls can control what data is allowed in or out of a network. Firewalls can be created with hardware or software.Proxy Server

Proxy Servers serve 3 main purposes. Disguise an end users actual identity using NAT. Cache requests to save bandwidth. Control content permitted to be requested from the Internet.

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Wireless Access Point

A Wireless Access Point (WAP) is basically the same thing as a hub, but the connections are made via the airwaves rather than cable.


Basic DHCP Server

DHCP is a TCP/IP service used to dynamically assign IP addresses on a network. A DHCP server is responsible for managing the pool of IP addresses available to be used on the network. Some network devices have basic DHCP server functionality built into them.DNS Server

DNS is a TCP/IP service used to resolve host names to IP addresses. A DNS server is responsible for maintaining a hierarchical directory of names in a database and respond to client requests for name resolution.


CSU/DSU

A Channel Service Unit/Data Service Unit is a hardware device which converts data frames used on a LAN into data frames used on a WAN. Typically a CSU/DSU will be used to connect a T1 line to a local network.

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Load Balancer

Load balancers are used when there are more than on line of communication available. Load balancers help to divide communication evenly between the different communication lines.Bandwidth Shaper

Bandwidth shapers are very similar to load balancers in that they are used to help make communication more efficient. The difference is that bandwidth shapers provide a much higher level of control over what data gets sent where and when.



Describe what some of the various network devices are and when they would be used.

Video 9 Routing

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In this video

Understanding Routing Tables Static vs. Dynamic Routing Routing Protocols Distance Vector Routing Link State Routing What is Convergence? IGP vs. EGP


Understanding Routing Tables

Routing tables are used by network devices in order to determine where a packet should be sent in an attempt to get it routed to its final destination.


Static vs. Dynamic Routing

Static Routing All routers have to have their routing table configured and updated manually. Dynamic Routing Routers communicate with each other to share their routing information with each other.

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Hi! Im a router! I am attached to Network A over here and Network B over here.

A

B


AB

I have been pre-configured with this information, but that is all I know right now.

A

B

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C A

AB

Hi there! Im a router too! I not only know about Network A, but the other side of me is connected to Network C.

C

A

B


C A1 Hop -

AB C

Great, I will keep that in mind if anyone over here is looking for Network C.

C

A

B


C A1 Hop -

AB C

And as long as we are sharing information, did you know that I am also connected to Network B?

C

A

B

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C A B - 1 Hop

1 Hop -

AB C

No I didnt, but I will make a note of that for future reference.

C

A

B


C A B - 1 Hop

1 Hop -

AB C

B D,E

Hello. Im also a router. Not only am I connected to Network B, but the other side of me is connected to Networks D & E.

C

A

B

D E


C A B - 1 Hop

1 Hop -

AB C D- 1 Hop E - 1 Hop

B D,E

Awesome, I will keep that in mind if anyone over here is looking for those networks.

C

A

B

D E

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C A B - 1 Hop

1 Hop -


B D,E

As long as we are sharing information, I am also connected to Network A?

C

A

B

D E


C A B - 1 Hop

1 Hop -


1 Hop -

B D,E A

Good to know.

C

A

B

D E


C A B - 1 Hop

1 Hop -


1 Hop -

B D,E A

And here is something really cool! On the other side of Network A is another router.

C

A

B

D E

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C A B - 1 Hop

1 Hop -


1 Hop -

B D,E A

No way!!!

C

A

B

D E


C A B - 1 Hop

1 Hop -


1 Hop -

B D,E A

Yes way, and that router is also connected to Network C.

C

A

B

D E


C A B - 1 Hop

1 Hop -


B D,E A 2 Hops - C1 Hop -

Cool, I will update my information.

C

A

B

D E

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C A B - 1 Hop

1 Hop -



Hey you, the router on Network A! I just found out about another router on Network B.

C

A

B

D E


C A B - 1 Hop

1 Hop -



Yeah, so what.

C

A

B

D E


C A B - 1 Hop

1 Hop -



Well, that router is also connected to Networks D & E. Just thought you might want to know.

C

A

B

D E

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C A B - 1 Hop D- 2 2 Hops E -HopsHey, that is good information. Thanks.

1 Hop -



C

A

B

D E


C A B - 1 Hop D- 2 2 Hops E -Hops

1 Hop -



All 3 router are now completely aware of all 5 networks.

C

A

B

D E


C A B - 1 Hop D- 2 2 Hops E -Hops

1 Hop -



And they all lived happily ever after. THE END

C

A

B

D E

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Routing Protocols

Distance Vector Routing Each router communicates all the networks it knows about to the other routers to which it is directly attached. Communication takes place on a regular basis. Link State Routing Each routers builds a map of the entire network. LSAs (Link State Advertisements) are used to communicate information about networks they are connected to. Communication only takes place when a change has been made.


Distance Vector Protocols

RIP (Routing Information Protocol) Maximum 15 hops. Originally had updates sent every 30 seconds. Does not support authentication. Uses broadcast communication. RIPv2 Maximum 15 hops. Supports authentication. Uses multicast communication. BGP (Border Gateway Protocol) Core routing protocol of the Internet. Typically used by ISPs.


Link State Protocols

OSPF (Open Shortest Path First) Used in medium to large networks. Bases its paths off link states. Can also use cost metrics to give preference to certain paths. IS-IS (Intermediate System to Intermediate System) Intermediate system is another name for a router. Originally designed with the OSI model.

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Hybrid Routing Protocols

EIGRP (Enhanced Interior Gateway Routing Protocol) Evolved from IGRP. Uses the Diffusing-Update Algorithm (DUAL). Each router keeps a copy of its neighbors routing tables. Each router periodically sends out a hello packet to keep track of the state of its neighbors.


What is Convergence?

When changes are made to a network every router on the network will need to make the appropriate changes to their routing tables in order to accommodate the changes. This could be the addition or deletion of a router or could simply be a change in metrics for a path. Convergence is the process of all routers becoming aware of changes to a network.


IGP vs. EGP

IGP (Interior Gateway Protocol) A routing protocol used to exchange information between routers within a LAN. EGP (Exterior Gateway Protocol) A routing protocol used to route information outside a local network, typically out to the Internet.

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Explain what a routing table is and know how to read one. Explain the differences between static and dynamic routing. Describe the difference between Link State and Distance Vector routing protocols. Explain the differences between Interior and Exterior routing protocols.

Video 10 Wireless Networking


In this video

Benefits of Wireless Networking Components of a Wireless Access Point (WAP) Where to Place a WAP Wireless Networking Standards How to Secure a Wireless Network Setting up a Wireless Access Point

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Benefits of Wireless Networking

No More Cables!!! Easier to install. Connect networks through walls and other obstacles. Quickly allow temporary access. Equally secure???


Components of a Wireless Access Point

BSS (Basic Service Set) ESS (Extended Service Set) SSID (Service Set Identifier) ESSID (Extended Service Set Identifier) BSSID (Basic Service Set Identifier) BSA (Basic Service Area)


Where to Place a WAP

The placement of your WAP is very important. There are many factors which will help you determine where to place your WAP. Where are the wireless clients located? How far can the WAP send and receive its signals? Are you using a directional antenna? Do you need to prevent certain areas from receiving the wireless signal?

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Wireless Networking Standards 802.11a Uses the 5GHz frequency. Data rates up to 54Mbps. Ranges less than 100 feet and easily obstructed. 802.11b Uses the 2.4GHz frequency. Data rates up to 11Mbps. Ranges up to 300 feet outdoors and 100 feet indoors. 802.11g Uses the 2.4GHz frequency. Data rates up to 54Mbps. Ranges up to 300 feet outdoors and 100 feet indoors. 802.11n Uses both the 2.4GHz and 5GHz frequencies. Data rates up to 100Mbps. Ranges up to 1000 feet.


RF Channels used by 802.11 b/g


RF Channels used by 802.11a

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How to Secure a Wireless Network

Disable SSID Broadcast If attackers do not see the presence of a WAP then they may think there is no wireless network to attack. MAC Filtering You can specify what computers can connect to your WAP based upon the MAC address of their wireless network card.



WEP (Wired Equivalency Privacy) It was used in the early stages of wireless networking. It is very easy to configure. It provides encryption for all data transmitted over the wireless network. It originally used a 40 bit encryption key, but later advanced to using 128 bit encryption. It was later found to be very easily cracked.



WPA (Wi-Fi Protected Access) Designed as an improvement to WEP. It utilizes TKIP which uses a hashing algorithm to scramble the encryption keys. It uses the Extensible Authentication Protocol (EAP) which is based off public-key encryption technology which is a much more secure way to verify authorized network users.

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802.1x Requires the use of Certificates and RADIUS. Certificates can be used to provide a higher level of authentication of the user and/or computer attempting to connect. A RADIUS server is used to centralize the connection requests to the wireless network.


Setting up a Wireless Access Point

Lets go take a look



Explain the benefits of using wireless networking. Describe the components of a wireless access point (WAP). Describe the different wireless networking standards. Know how to secure a wireless network. Install a wireless access point.

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Video 11 Networking Command Line Tools


In this video

IPCONFIG/IFCONFIG/ARP PING/ARP PING TRACERT/TRACEROUTE MTR NETSTAT/NBTSTAT/ROUTE NSLOOKUP/DIG/HOST


IPCONFIG/IFCONFIG/ARP

IPCONFIG Used to view TCP/IP configuration in the Windows operating system. IFCONFIG Used to view TCP/IP configuration in the Unix, Linux, and Macintosh operation systems. ARP Used to view and manage the ARP cache.

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PING/ARP PING

PING Used to check connectivity between networking devices. ARP PING Used to check connectivity between networking devices using their MAC addresses. Can only be used within a single subnet. Requires a 3rd party utility.


TRACERT/TRACEROUTE

The TRACERT command is used in the Windows operating system to view the entire path a packet takes to get from one device to another. Unix, Linux, and Macintosh operating systems have a similar utility called TRACEROUTE.


MTR

The MTR utility is used by the Unix and Linux operating systems to view the entire path a packet takes to get from one device to another while also displaying additional statistics about each node along the way. The Windows operating system has a utility called PATHPING which does basically the same thing. It is kind of like taking PING and TRACERT and putting them together to create a more powerful utility.

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NETSTAT/NBTSTAT/ROUTE

NETSTAT Used to display TCP/IP statistics and connections. NBTSTAT Used to display NetBIOS statistics to assist in troubleshooting name resolution issues. ROUTE Used to display and manage the routing table.


NSLOOKUP/DIG/HOST

NSLOOKUP Used by the Windows operating system to troubleshoot DNS name resolution issues. It has both interactive and non-interactive modes. DIG Used by the Unix, Linux, and Macintosh operating systems for the same purpose. NSLOOKUP can also be used in these operating systems, but DIG is considered to be more powerful. It does not have an interactive mode. HOST Used by the Unix and Linux operating system to do reverse lookups on an IP address. NSLOOKUP is used for this purpose in Windows.


Working with Networking Command Line Tools

Lets go take a look

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Describe what some of the various network command line tools are and when they would be used.

Video 12 Network Performance Optimization


In this video

Reasons Uptime Latency Sensitivity High Bandwidth Applications QoS Traffic Shaping Load Balancing Fault Tolerance Caching Engines

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Reasons

Uptime A measure of time that a network is running. It is the opposite of downtime. Different business solutions require different levels of uptime. Latency Sensitivity Some applications require very quick delivery (low latency) of data in order to be effective. High Bandwidth Applications Certain applications require the availability of a high level of bandwidth to transfer large quantities of data.


QoS

Quality of Service (QoS) is a strategy used to control the flow of network traffic. With QoS administrators can provide preferential delivery for the applications which need it.


Traffic Shaping

One of the methods administrators use to ensure QoS is traffic shaping. Traffic Shaping is used to enforce the control of network traffic. Generally traffic should be shaped based upon different priority factors. Examples: Users Applications Time of Day

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Load Balancing

Load balancing is a general term which defines the use of more than one (insert variable) to provide a service. Client needs are satisfied by the first available (insert variable). Sometimes client needs can be satisfied by all available (insert variable). Variables: Servers Hard Drives Transmission Lines


Fault Tolerance

If something is fault tolerant then it means that in the event of a failure(fault) it will continue to function(tolerance). Fault tolerance can and should be implemented at all levels of a network: Hard Drives Power Supply Network Adapters Servers Routers Network Links


RAID

RAID 0 Disk Striping RAID 1 Disk Mirroring and Duplexing RAID 5 Disk Striping with Parity

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Caching Engines

Caching engines are used to store information so it does not have to be retrieved off the network multiple times. A proxy server is an example of a caching engine.



Describe why it is important to have an optimized network. Explain how an administrator can use QoS and traffic shaping to keep control over the flow of network traffic. Explain how load balancing and fault tolerance are used to keep network services highly available. Describe what a caching engine is.

Video 13 Network Tools

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In this video

Cable Strippers Snips Crimpers Punch Down Tool Cable Testers/Certifiers TDR/OTDR Toner Probe Voltage Event Recorder Multimeter Protocol Analyzer Temperature Monitor Butt Set


Cable Strippers

Cable strippers are used to strip off the outer insulation of a cable when getting it ready for a connector.


Snips

Snips are used to cut cables.

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Crimpers

Crimpers are used to attach a connector on the end of a cable.


Punch Down Tool

A punch down tool is used to connect wire to a punch down block.


Cable Testers/Certifiers

Cable testers are used to test whether a cable is working properly. Certifiers are used to test and validate whether a cable is ready to handle certain levels of throughput.

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TDR/OTDR

A Time Domain Reflectometer (TDR) is used to check the continuity of a copper cable. An Optical Time Domain Reflectometer (OTDR) is used to check the continuity of a fiber optic cable. These tools can be used to help locate where there is a break in the cable.


Toner Probe

A toner probe is used to locate the end of a cable. It is made up of 2 components, a tone generator and a probe.


Voltage Event Recorder

A voltage event recorder is used to monitor the quality of the power coming from a wall outlet.

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Multimeter

A multimeter is used to test a variety of information about cables, connectors and outlets.


Protocol Analyzer

A protocol analyzer is used to analyze network protocols.Temperature Monitor

A temperature monitor is used to monitor the temperature and humidity of a server room and alert an administrator if there is a drastic change.Butt Set

A butt set is used to allow an administrator to butt in to a communication line.



Describe what some of the various network tools are and when they would be used.

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Video 14 Network Monitoring


In this video

Network Monitoring Utilities Packet Sniffers Port Scanners IDS/IPS System Logs Event Logs History Logs


Network Monitoring Utilities

There are many reasons for monitoring a network. Performance Maintenance Security There are many different utilities which can be used to monitor a network. Packet Sniffers Port Scanners IDS/IPS

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Packet Sniffers

Packet sniffers can be either hardware or software. They are used to capture and listen to transmissions which are travelling on a network. They can be used to help find vulnerabilities in a network and notify you of a possible intrusion.


Port Scanners

Port scanners are used to look for open ports on a network or a system. Typically port scanning is done through software. Port scanners are used by administrators and attackers to recognize potential vulnerabilities.


IDS/IPS

Intrusion Detection Software(IDS) Used to watch for network patterns which could represent an attack on a system or network. A log is maintained and/or an administrator can be notified. Intrusion Prevention Software(IPS) Generally has all the capability of IDS. It is also designed to automatically attempt to stop the attack along with notifying an administrator.

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System Logs

System logs maintain information about all system related events.Event Logs

Event logs maintain events which take place on a system.History Logs

History logs maintain a history of events which take place on a system or network.


Working with Logs

Lets go take a look



Describe the purpose of using network monitoring utilities. Describe the purpose of logging.

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Video 15 Documentation


In this video

Why is documentation so important? What should I document? Wiring Schematics Physical and Logical Network Diagrams Baselines Network Policies Network Procedures Network Configurations Regulations


Why is documentation so important?

Training It is easier to train new administrators when there is good documentation available to them familiarize themselves with the environment. Troubleshooting Most problems occur more than once. It is easier to reference documentation than to troubleshoot the same problem repeatedly. Reporting It is easier to justify your work and solidify your purpose when you have good documentation to give to your superiors.

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What should I document?

Everything!!!!!Hardware Software Network Topology Wiring Layout Server Configuration Network Services Network Procedures


Wiring Schematics

Wiring schematics become increasingly important as a network grows. They need to be complex enough to thoroughly explain the entire network while simple enough for a new administrator to understand.


Physical and Logical Network Diagrams

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Baselines

Baseline readings are an integral component to maintaining optimal network performance. These readings are typically taken when the network is functioning normally. When there is a performance problem on the network new performance readings are taken and need to be compared against the original baseline readings. New baseline readings should be taken periodically to help recognize trends in changes to network performance.


Network Policies

Network policies are used to establish rules and guidelines regarding network usage and conduct. It is very important to review and modify these policies as the network and business needs change. Examples: Network Usage Policy Internet/Email Usage Policy External Software Policy


Network Procedures

Network procedures are used to establish how networking tasks are to be performed. There are many procedures that a network administrator is responsible for doing. Having good documentation of these procedures will help guide an administrator in appropriately managing the network.

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Network Configuration

It is very important to not only have wiring schematics, physical, and logical network diagrams, but to also have detailed configuration documentation of all significant networking devices on a network.


Regulations

Regulations are very similar to policies in the sense that they establish rules and guidelines. The difference is that policies are created within an organization and regulations are the actual legalities which are created by the government.



Explain the importance of having good documentation? Recognize and understand wiring schematics, physical, and logical network diagrams. Describe the purpose of using baselines. Create network policies, procedures, and configuration documentation. Understand the importance of following regulations.

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Video 16 Troubleshooting


In this video The Process of Troubleshooting Gather Information. Whos affected? Whats Changed? Why is this happening? Can I handle it? Find a solution. Try it. See if it worked. DOCUMENT EVERYTHING!!! Common Issues Physical Issues Logical Issues Issues to Escalate Wireless Issues


The Process of Troubleshooting

Gather Information. Whos affected? Whats Changed? Why is this happening? Can I handle it? Find a solution. Try it. See if it worked. DOCUMENT EVERYTHING!!!

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Common Issues

Physical Issues Crosstalk Near End Crosstalk (NEXT) Far End Crosstalk (FEXT) Attenuation Collisions Shorts Open Impedance Mismatch (echo) Interference


Common Issues

Logical Issues Port Speed Port Duplex Mismatch Incorrect VLAN Incorrect IP Address Wrong Gateway Wrong DNS Wrong Subnet Mask


Common Issues

Issues to Escalate Switching Loop Routing Loop Route Problems Proxy ARP Broadcast Storms

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Common Issues

Wireless Issues Interference Incorrect Encryption Incorrect Channel Incorrect Frequency ESSID Mismatch Standard Mismatch (802.11 a/b/g/n) Distance Bounce Incorrect Antenna Placement



Effectively troubleshoot network problems. Describe common connectivity issues.

Video 17 Network Security

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In this video

Firewalls Other Security Devices Network Access Security Filtering Tunneling and Encryption Remote Access Protocols User Authentication Device Security Common Security Threats


Firewalls

Firewalls are used to control the flow of data. They can be either network based or host based. Different types of firewalls function at different layers of the OSI model. Application layer firewalls have added functionality such as: Stateful Inspection Scanning Services Content Filtering Signature Identification Firewalls can also be used to create perimeter networks (DMZ).


Firewalls

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Other Security Devices

An Intrusion Detection System(IDS) is used to help an administrator recognize a possible attack on a network or system. An Intrusion Prevention System(IPS) has similar functionality to an IDS, but will actively make changes to lock down the network or system if a potential intrusion is present. A VPN concentrator is basically a hardware based VPN server. It is used to setup a secure VPN connection with the remote client before passing them on through to the internal network.

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