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A+ Guide to Managing and Maintaining Your PC, 7e
Chapter 17 Networking Essentials
Objectives
• Identify the different elements of a network • Differentiate network classification according to categories, namely, size and protocol • Understand different networking technologies • Differentiate the different medium used in networking • Identify essential hardware used in networking • Understand what is an IP address and how it works • Understand basic networking protocol A+ Guide to Managing and Maintaining Your PC, 7e 2
Networking Definition
• What is a Computer network – Two or more computers communicating through a medium whether in a cable or in a wireless manner or both.
• Three elements of a network – Source (transmitter) – Medium (line, circuit or cable) – Sink (receiver) A+ Guide to Managing and Maintaining Your PC, 7e 3
Category of Network according to size and area
• Categorized by size and physical area covered – PAN (Personal Area Network) – LAN (Local Area Network) – MAN (Metropolitan Area Network) – WAN (Wide Area Network) A+ Guide to Managing and Maintaining Your PC, 7e 4
Category of Network according to size and area
WAN MAN LAN PAN A+ Guide to Managing and Maintaining Your PC, 7e 5
Category of Network according to size and area
• Categorized by size and physical area covered –
PAN
– devices like PDA, cellphone communicating in very close range/proximity up to 100 meters.
–
LAN
– devices interconnected in a limited and close type area like school laboratory, a building or home.
– –
MAN
– networks that span normally wider geographic location of up to 30 miles like a city or a metropolitan.
WAN
– networks that span beyond 30 miles a whole country or country-to-country etc. A good example of WAN is the Internet.
A+ Guide to Managing and Maintaining Your PC, 7e 6
Category of Network according to Topology
•
Topology
– is the physical and logical layout of the network that interconnects different nodes (e.g. computer, network devices).
• Main topologies: Bus, Ring, Star, and Mesh • Hybrid topologies: star-bus, star-ring A+ Guide to Managing and Maintaining Your PC, 7e 7
Bus Topology
• Bus topology – Consists of cables connecting PCs or file servers – Visualizes connections as chain links – Terminator attached to each end of bus cable segment • Transmitting packet across bus – Detected by all nodes on segment – Given time limit to reach destination • IEEE (Institute of Electrical and Electronics Engineers) – Develops standards for network cabling, transmission – Specifies length of bus segment A+ Guide to Managing and Maintaining Your PC, 7e 8
A+ Guide to Managing and Maintaining Your PC, 7e 9
Bus Topology (continued)
• Terminator signals end of physical segment – Functions as resistor that absorbs signal • Terminator critical on bus networks – Prevents signal reflection back on to covered path • Advantages of bus design – Requires less cable than other topologies – Easy to extend bus with a workstation • Disadvantages of bus topology – High management costs • Single defective node can take down entire network – Can become quickly congested with network traffic A+ Guide to Managing and Maintaining Your PC, 7e 10
Ring Topology
• Ring topology: continuous data path – Workstations attached to cable at points around ring • Transmitting data across ring topology – Goes around ring to reach destination – Continues until ends at source node • Advantages to ring topology – Easier to manage than bus – Handles high volume network better than bus – Suited to transmitting signals over long distances • Disadvantages to ring topology – More expensive to implement than bus – Fewer equipment options than bus A+ Guide to Managing and Maintaining Your PC, 7e 11
A+ Guide to Managing and Maintaining Your PC, 7e 12
Star Topology
• Star topology: multiple nodes attached to central device (hub, switch, router) – Cable segments radiate from center like a star – Example: workstations connected to switch • Advantages of star topology – Start-up costs comparable to ring topology – Easier to manage, defective nodes quickly isolated – Easier to expand by connecting nodes or networks – Offers better equipment and high-speed options • Disadvantages of star topology – Failure of central device may cause network failure – Requires more cable than bus A+ Guide to Managing and Maintaining Your PC, 7e 13
Hands-on Networking Fundamentals 14
Mesh Topology
• Mesh topology – Every node connected to every other node in network – Provides network with fault tolerance • Fault tolerance: built-in protection against failure • If link breaks, nodes can still communicate – Alternate communication paths increase as number of nodes increase • Mesh topology used less on LANs – Expensive to implement • Mesh topology often used in MANs and WANs Hands-on Networking Fundamentals 15
Hands-on Networking Fundamentals 16
Star-Bus Hybrid Topology
• Star-bus (star-wired) topology – Each radiating finger is separate logical bus segment – Each segment terminated at both ends • Advantages of star-bus topology – No exposed terminators – Connect multiple central devices to expand network – Connection between central devices is a backbone • Backbone enables high-speed communication – Central devices have built-in intelligence – Many equipment and high-speed options available Hands-on Networking Fundamentals 17
Star-Ring Hybrid Topology
• Star-ring (star-wired) topology – Hub or access unit acts as linking device – Transmission using logical communication of ring – No need for built-in terminators Hands-on Networking Fundamentals 18
Activity - Drawing Network Topologies • Using the blank sheet of paper that will be provided make a hand-drawn sketch of different network topologies, namely, Bus, Star, Ring and Mesh.
• This is worth
20 points
A+ Guide to Managing and Maintaining Your PC, 7e 19
Networking Technologies
• Bandwidth: data transmission rate or the number of bits that can be transmitted over a network at one time (e.g. 56Kbps, 10Mbps, 1Gbps). It is a theoritical or potential speed of a network.
• Data throughput: actual network transmission speed • Latency: delays in network transmissions A+ Guide to Managing and Maintaining Your PC, 7e 20
Networking Technologies (cont’d.)
• Internet Service Provider (ISP) – Required for Internet connection – Upload speed is slower than download speed • Communicating devices require same protocol –
Protocol
is a set of rules that governs interaction and in a network environment it means the rule that governs the communication between computers.
– Internet protocol: TCP/IP (group of protocols) – Data is broken into segments, segment are put into packets
Figure 17-1
Use an ISP to connect to the Internet Courtesy: Course Technology/Cengage Learning A+ Guide to Managing and Maintaining Your PC, 7e 21
• Networking Technologies – Speed and Common Uses
Technology Speed or Speed Range Common Uses
Dial-up or regular telephone ADSL (Assymetric DSL) Up to 56 Kbps Up to 640Kbps upstream and up to 8 Mbps downstream Slow access to ISP using modem and a telephone line Commonly used by ISP today that are more affordable for their customers SDSL (Symmetric DSL) Fiber Optic, Optical Carrier Level Up to 2.3 Mbps Up to 50Mbps and Up to 160Gbps respectively Still used by today’s ISP but more suited for business. Both upstream and downstream are of the same speed.
Used as dedicated line for ISP to business and as an Internet backbone respectively.
Used for dedicated line for businesses like banks to ISP T1, T2 & T3 1.54Mbps, 6Mpbs and 45Mbps respectively 802.11a, 802.11g, 802.11n
Up to 54Mbps, 54Mpbs and 160Mbps respectively Used for wireless networking Ethernet, Fast Ethernet, Gigabit Ethernet 10Mpbs, 100Mbps and 1Gbps respectively
Table 17-1
Networking technologies Used in Local Area Network A+ Guide to Managing and Maintaining Your PC, 7e 22
Broadband Technologies
• Connect to the Internet – Cable modem, DSL, fiber-optic, satellite, ISDN (Integrated Services Digital Network) • Cable modem communication – Uses existing cable lines – Always connected (always up) – TV signals and PC data signals share same coax cable – Cable modem converts PC’s digital signals to analog A+ Guide to Managing and Maintaining Your PC, 7e 23
Broadband Technologies (cont’d.)
• DSL (Digital Subscriber Line) – Group of broadband technologies • Wide range of speeds – Uses ordinary copper phone lines and unused voice frequencies – Always connected • Some DSL services offer connect on demand – Asymmetric DSL (ADSL): one upload speed, faster download speed – Symmetric DSL (SDSL): equal bandwidths in both directions A+ Guide to Managing and Maintaining Your PC, 7e 24
Broadband Technologies (cont’d.)
• Cable modem and DSL – Sometimes purchased on a sliding scale – Cable modem shares TV cable infrastructure with neighbors • Service may become degraded – DSL uses dedicated phone line • Must filter phone line static – Similar setup for both – Installation completed by provider or user – Both use PC network port or USB port to connect cable modem or DSL box A+ Guide to Managing and Maintaining Your PC, 7e 25
Broadband Technologies (cont’d.)
• Satellite provides high-speed Internet connections in remote areas – Available everywhere (airplanes) – Disadvantage: latency when uploading
Figure 17-5
Communication by satellite can include television and Internet access Courtesy: Course Technology/Cengage Learning A+ Guide to Managing and Maintaining Your PC, 7e 26
Broadband Technologies (cont’d.)
• Fiber optic dedicated point-to-point (PTP) – No line sharing – Broadband fiber-optic cable • Television, Internet data, voice communication – Verizon technology: Fiber Optic Service (FiOS) – Cabling endpoints: carrier dependent – Upstream and downstream speeds and prices vary A+ Guide to Managing and Maintaining Your PC, 7e 27
Wireless Technologies
• Use radio waves or infrared light – Useful in places where cables difficult to install • 802.11 wireless (Wi-Fi or Wireless Fidelity) – 802.11g and 802.11b
• 2.4 GHz frequency Range, 100m distance – 802.11n: Multiple input/multiple output (MIMO) • 2.4 GHz and 5 GHz range, 600 Mbps speed possible – 802.11a: no longer widely used – 802.11k and 802.11r
• Manage connections between wireless devices and access points A+ Guide to Managing and Maintaining Your PC, 7e 28
Wireless Technologies (cont’d.)
• Security methods required – Encrypt data • WEP (Wired Equivalent Privacy), WPA (Wi-Fi Protected Access), WPA2 (Wi-Fi Protected Access 2) – Disable SSID broadcasting • SSID: name of the wireless access point – Filter MAC addresses • MAC (Media Access Control) address: 6-byte number uniquely identifying network adapter • Prevents uninvited guests from using wireless LAN • Does not prevent others from receiving data in the air A+ Guide to Managing and Maintaining Your PC, 7e 29
Activity – Checking ISP Broadband prices and speed • Using the blank sheet of paper that will be provided make a table for the speed and prices from FSM telecom for the technologies listed below
– ADSL – SDSL – T1,T2,T3 (if any) • Check out from FSM Telecom website www.telecom.fm
• This is worth
20 points
A+ Guide to Managing and Maintaining Your PC, 7e 30
Media used in Networking
• Two types of Medium – Wireless or Unguided – Wired or Guided Media A+ Guide to Managing and Maintaining Your PC, 7e 31
Different types of Guided Media or Cable
A+ Guide to Managing and Maintaining Your PC, 7e
Table 17-2
Variations of Ethernet and Ethernet cabling 32
Figure 17-17
The most common networking cable for a local network is UTP cable using an RJ-45 connector. Courtesy: Course Technology/Cengage Learning
Figure 17-18
Coaxial cable and a BNC connector are used with ThinNet Ethernet. Courtesy: Course Technology/Cengage Learning
Figure 17-19
Fiber-optic cables contain a glass core for transmitting light. Courtesy: Course Technology/Cengage Learning A+ Guide to Managing and Maintaining Your PC, 7e 33
Most Common Cable for LAN
A+ Guide to Managing and Maintaining Your PC, 7e
Table 17-2
Variations of Ethernet and Ethernet cabling 34
Connector Used for Twisted Pair
RJ-45 Connector A+ Guide to Managing and Maintaining Your PC, 7e 35
Unshielded Twisted Pair
• Unshielded Twisted-Pair Cable (UTP) – Consists of wire pairs within insulated outer covering – Has no shielding between wires and encasement • UTP is most frequently used network cable • Reducing EMI (Electro Magnetic Interference) and RFI (Radio Frequency Interference) – Twist interior strands (like STP) – Build media filter into network equipment, workstation, and file connection servers A+ Guide to Managing and Maintaining Your PC, 7e
Table 17-2
Variations of Ethernet and Ethernet cabling 36
UTP Cable Types/Category
• UTP cables used in 10BaseT networks – Category 3: transmission rates up to 16 Mbps – Category 4: transmission rates up to 20 Mbps – Category 5 UTP has 100 Mbps transmission rate – Category 5e (enhanced) UTP vs. Category 5 UTP • 1 Gbps transmission rate • Uses better-quality copper • Has higher twist ratio for better EMI/RFI protection – Category 6 UTP • Wire pairs wrapped within insulating foil • Has fire resistant plastic sheath • 1 Gbps transmission rate A+ Guide to Managing and Maintaining Your PC, 7e
Table 17-2
Variations of Ethernet and Ethernet cabling 37
Standard in Twisted Pair Cabling
• Recommended by EIA/TIA – EIA/TIA 586A and EIA/TIA 586B – Either of the standards above could be used – Use Color Coding for Correct Wiring combination A+ Guide to Managing and Maintaining Your PC, 7e
Table 17-2
Variations of Ethernet and Ethernet cabling 38
Standard in Twisted Pair Cabling (cont’d)
A+ Guide to Managing and Maintaining Your PC, 7e
Table 17-2
Variations of Ethernet and Ethernet cabling 39
Types of Twisted Pair connections
• •
Straight connection
– When two different type of nodes are connected. For example a desktop PC to a hub or a switch.
Cross-over connection
– When two the same type of nodes are connected. For example a desktop PC is to connected to another desktop PC.
A+ Guide to Managing and Maintaining Your PC, 7e
Table 17-2
Variations of Ethernet and Ethernet cabling 40
Two Basic Networking Setup
• Peer-to-Peer – Two (or more) computers communicating each other in which either computer could act as a Server or a Client.
• Client and Server – One computer act as a Server or the computer who is solely responsible for distributing resources (like Database, Web connection) among the network and the rest act as a client or the who request resources from the Server.
A+ Guide to Managing and Maintaining Your PC, 7e
Table 17-2
Variations of Ethernet and Ethernet cabling 41
Hardware Used by Local Networks
• Hardware devices creating and connecting to networks – Desktop and laptop devices – Cables and their connectors – Hubs – Switches – Wireless access devices – Routers A+ Guide to Managing and Maintaining Your PC, 7e 42
Networking Adapters and Ports
• Ethernet network adapters and ports – Network adapter: direct connection to a network • Takes the form of a network interface card (NIC) • External devices connect using USB port • Provides RJ-45 port – Network cards provide status light indicators • Useful in troubleshooting – MAC (Media Access Control) address • Unique 48-bit (6-byte) number hard-coded on card by manufacturer • Identifies adapter on the network A+ Guide to Managing and Maintaining Your PC, 7e 43
Networking Adapters and Ports (cont’d.)
• WI-FI wireless adapters – 802.11b/g/n connections use a variety of devices – Laptops sold today have antenna embedded inside
Figure 17-16
Four different types of wireless network adapters: (a) wireless NIC that fits in a PCI slot; (b) onboard wireless with an antenna that can be moved; (c) PC Card wireless NIC with embedded antenna; and (d) wireless NIC that uses a USB port on a desktop or notebook computer. Courtesy: Course Technology/Cengage Learning A+ Guide to Managing and Maintaining Your PC, 7e 44
Cables and Connectors
• Types of Ethernet cabling: – Twisted-pair • Unshielded (UTP) and shielded twisted pair (STP) • Coaxial cable: single copper wire with braided shield – Fiber-optic: glass strands inside protective tubing • Ethernet types (categorized by speed): – 10-Mbps Ethernet – 100-Mbps or Fast Ethernet – 1000-Mbps or Gigabit Ethernet – 10-Gigabit Ethernet A+ Guide to Managing and Maintaining Your PC, 7e 45
Hubs and Switches
• Star topology: nodes connected to a centralized hub or switch • Hub: pass-through device – No regard for data • Switch: keeps a table of all devices connected to it – Determines path when sending packets • Network cables – Patch cable (straight-through cable): connects computer to hub or switch – Crossover cable: connects two like devices A+ Guide to Managing and Maintaining Your PC, 7e 46
Hubs and Switches (cont’d.)
• Some switches have uplink port for patch cable use • Some switches use auto-uplinking
Figure 17-24
An Ethernet network with three switches Courtesy: Course Technology/Cengage Learning A+ Guide to Managing and Maintaining Your PC, 7e 47
Wireless Access Points
• Allows wireless device connection to LAN – Devices communicate through access point – May double as a router
Figure 17-26
Nodes on a wireless LAN connect to a wired network by way of an access point. Courtesy: Course Technology/Cengage Learning 48 A+ Guide to Managing and Maintaining Your PC, 7e
Routers
Figure 17-27
A router stands between a local network and the Internet and manages traffic between them. Courtesy: Course Technology/Cengage Learning A+ Guide to Managing and Maintaining Your PC, 7e 49
Routers (cont’d.)
• DHCP (dynamic host configuration protocol) server – Provides IP addresses to network computers – Dynamic IP addressing • No need to assign, keep up with unique IP addresses • Router functions – Router – Switch – DHCP server – Wireless access point – Firewall with or without NAT redirection A+ Guide to Managing and Maintaining Your PC, 7e 50
Windows on a Network
• Client/server applications – Two computers and two applications involved – Communication occurs three levels • Hardware, operating system, application • Dependent on one computer addressing the other
Figure 17-31
A Web browser (client software) requests a Web page from a Web server (server software); the Web server returns the requested data to the client Courtesy: Course Technology/Cengage Learning A+ Guide to Managing and Maintaining Your PC, 7e 51
Layers of Network Communication
• Level 1: Hardware level – Root level of communication • Wireless or network cables • Phone lines or TV cable lines – Includes the network adapter and MAC address – Communication protocols used A+ Guide to Managing and Maintaining Your PC, 7e 52
Figure 17-32
Network communication happens in layers Courtesy: Course Technology/Cengage Learning A+ Guide to Managing and Maintaining Your PC, 7e 53
Layers of Network Communication (cont’d.)
• Level 2: Operating system level – Manages communication between itself and another computer using TCP/IP – Uses IP addressing
Figure 17-33
Computers on the same LAN use MAC addresses to communicate, but computers on different LANs use IP addresses to communicate over the Internet Courtesy: Course Technology/Cengage Learning A+ Guide to Managing and Maintaining Your PC, 7e 54
Layers of Network Communication (cont’d.)
• Level 3: Application level – Client communicates with another Internet application – Port number • Uniquely identifies computer application – Socket • IP address followed by a colon and port number • E-mail example: 36.60.30.5:25 • Web server example: 136.60.30.5:80 A+ Guide to Managing and Maintaining Your PC, 7e 55
Table 17-3
Common TCP/IP port assignments for client/server applications A+ Guide to Managing and Maintaining Your PC, 7e 56
Understanding IP Addresses and How They Are Used (cont’d.)
• IP address identifies network and host – Classes are based on the number of possible IP addresses in each network within each class
Table 17-4
Classes of IP addresses A+ Guide to Managing and Maintaining Your PC, 7e 57
Understanding IP Addresses and How They Are Used (cont’d.)
• Class D addresses: octets 224 through 239 – Multicasting • Class E addresses: octets 240 through 254 – Research
Figure 17-36
The network portion and host portion for each class of IP addresses Courtesy: Course Technology/Cengage Learning A+ Guide to Managing and Maintaining Your PC, 7e 58
Understanding IP Addresses and How They Are Used
• IP address: 32 bits long, made up of 4 bytes, each 8 bits long – Four decimal numbers separated by periods • 190.180.40.120
– Largest possible 8-bit number • 11111111 (255 decimal) – Largest possible decimal IP address • 255.255.255.255
• 11111111.11111111.11111111.11111111 binary – Octet: each of the four decimal numbers • 0 to 255, 4.3 billion potential IP addresses A+ Guide to Managing and Maintaining Your PC, 7e 59
Understanding IP Addresses and How They Are Used
• Converting a Decimal IP address to Binary: – Example • 192.168.5.1
– Use the 8 bits Octet per decimal number • 11111111 (255 decimal) – Use the Number system in Binary: • 2 7 2 6 • 128 64 2 5 32 2 4 16 8 2 3 4 2 2 2 2 1 1 2 0 A+ Guide to Managing and Maintaining Your PC, 7e 60
Converting IP address to binary
• For example in the IP Address 192.168.5.1 we want to convert first the 1 st Octet which is 192 – Simply Go to the nearest number below and subtract: • 2 7 2 6 2 5 2 4 2 3 2 2 2 1 2 0 • 128 64 32 16 8 4 2 1 – From above the nearest number for 192 is 128 so we have 192 128=64 – So, we put 1 under that – 128 64 32 – 1 16 8 4 2 1 – And then the nearest number of 64 is simply 64. So we put 1 under 64 also.
– 128 – 1 64 1 32 16 8 4 – And since 64-64 =0 then we put 0 on the rest A+ Guide to Managing and Maintaining Your PC, 7e 2 1 61
Converting IP address to binary
• So we have finally: – 128 64 32 16 8 4 – 1 1 0 0 0 0 – Hence the Binary format for 192 is 11000000 • How about the 168 in the 2 nd Octet.
2 0 1 0 • How about the 5 in the 3 rd Octet and the 1 in the 4 th Octet.
A+ Guide to Managing and Maintaining Your PC, 7e 62
Checking IP Address
• To check in your own IP Address go to Start Run then type
cmd
and press enter.
• On DOS Command prompt type ipconfig then press enter.
• To check the different IP Addresses on a certain domain name, say www.facebook.com
• Type tracert www.facebook.com
A+ Guide to Managing and Maintaining Your PC, 7e 63
Activity on IP Addressing
• Convert the IP address on your PC to a binary format.
• Using Tracert command trace the following domain: – Set A : www.facebook.com
– Set B : www.twitter.com
• On each given IP address identify what Class each IP address it belongs to.
A+ Guide to Managing and Maintaining Your PC, 7e 64
Understanding IP Addresses and How They Are Used (cont’d.)
• Subnet masks – Group of ones followed by a group of zeros – Classful subnet masks: all ones, all zeros in an octet – Classless subnet mask: mix of zeros and ones
Table 17-5
Default subnet masks for classes of IP addresses – Take note that the one in
1s
is the
Network Portion
and the one in
0s
is the
Host portion
.
A+ Guide to Managing and Maintaining Your PC, 7e 65
Understanding IP Addresses and How They Are Used (cont’d.)
• Classless subnet masks – Uses Default Subnet Mask for Class A to C
Class
A B C
Default subnet Mask
255.0.0.0
255.255.0.0
No. of possible Networks
127 16,000 255.255.255.0 2 Million
No. of possible Hosts
16Millions 65,000 254
Table 17-5
Default subnet masks for classes of IP addresses A+ Guide to Managing and Maintaining Your PC, 7e 66
Understanding IP Addresses and How They Are Used (cont’d.)
• Public IP addresses: available to the Internet • Private IP addresses: used on private intranets – Use router with NAT redirection for Internet access – IEEE recommendations • 10.0.0.0 through 10.255.255.255
• 172.16.0.0 through 172.31.255.255
• 192.168.0.0 through 192.168.255.255
Table 17-6
Reserved IP addresses A+ Guide to Managing and Maintaining Your PC, 7e 67
Subnetting
• Separates network – Multiple logically defined segments (subnets) • Geographic locations, departmental boundaries, technology types • Subnet traffic separated from other subnet traffic • Reasons to separate traffic – Enhance security – Improve performance – Simplify troubleshooting Network+ Guide to Networks, 5 th Edition 68
Classful Addressing in IPv4
Figure 4-8 IP addresses and their classes • First, simplest IPv4 addressing type • Adheres to network class distinctions • Recognizes Class A, B, C addresses Network+ Guide to Networks, 5 th Edition 69
Classful Addressing in IPv4 (cont’d.)
• Network information (network ID) – First 8 bits in Class A address – First 16 bits in Class B address – First 24 bits in a Class C address • Host information – Last 24 bits in Class A address – Last 16 bits in Class B address – Last 8 bits in Class C address Network+ Guide to Networks, 5 th Edition 70
Classful Addressing in IPv4 (cont’d.)
Figure 10-1 Example IPv4 addresses with classful addressing Network+ Guide to Networks, 5 th Edition 71
Classful Addressing in IPv4 (cont’d.)
• Drawbacks – Fixed network ID size limits number of network hosts – Difficult to separate traffic from various parts of a network Network+ Guide to Networks, 5 th Edition 72
IPv4 Subnet Masks
• Identifies how network subdivided • Indicates where network information located • Subnet mask bits – 1: corresponding IPv4 address bits contain network information – 0: corresponding IPv4 address bits contain host information Network+ Guide to Networks, 5 th Edition 73
IPv4 Subnet Masks (cont’d.)
Table 10-1 Default IPv4 subnet masks • Network class – Associated with default subnet mask Network+ Guide to Networks, 5 th Edition 74
IPv4 Subnet Masks (cont’d.)
Table 10-2 ANDing • ANDing – Combining bits • Bit value of 1 plus another bit value of 1 results in 1 • Bit value of 0 plus any other bit results in 0 – ANDing logic • 1: “true”, 0: “false Network+ Guide to Networks, 5 th Edition 75
IPv4 Subnet Masks (cont’d.)
Figure 10 2 Example of calculating a host’s network ID • ANDing example – Address’s fourth octet • Any combination of 1s and 0s • Results in network ID fourth octet of 0s Network+ Guide to Networks, 5 th Edition 76
Reserved Addresses
• Cannot be assigned to node network interface; used as subnet masks • Network ID – Bits available for host information set to 0 – Classful IPv4 addressing network ID ends with 0 octet – Subnetting allows network ID with other decimal values in last octet(s) • Broadcast address – Octet(s) representing host information equal all 1s – Decimal notation: 255 Network+ Guide to Networks, 5 th Edition 77
IPv4 Subnetting Techniques
• Subnetting breaks classful IPv4 addressing rules – IP address bits representing host information change to represent network information • Reduce usable host addresses per subnet • Hosts, subnets available after subnetting related to host information bits borrowed Network+ Guide to Networks, 5 th Edition 78
IPv4 Subnetting Techniques (cont’d.)
Table 10-3 IPv4 Class B subnet masks Network+ Guide to Networks, 5 th Edition 79
IPv4 Subnetting Techniques (cont’d.)
Table 10-4 IPv4 Class C subnet masks • Class C network – Fewer subnets than Class B – Less hosts per subnet than Class B Network+ Guide to Networks, 5 th Edition 80
Calculating IPv4 Subnets
• Formula: 2
n
−2=Y –
n
: number of subnet mask bits needed to switch • From 0 to 1 – Y: number of resulting subnets • Example – Class C network • Network ID: 199.34.89.0
• Want to divide into six subnets Network+ Guide to Networks, 5 th Edition 81
Calculating IPv4 Subnets (cont’d.)
Table 10-5 Subnet information for six subnets in an example IPv4 Class C network Network+ Guide to Networks, 5 th Edition 82
Calculating IPv4 Subnets (cont’d.)
• Class A, Class B, and Class C networks – Can be subnetted • Each class has different number of host information bits usable for subnet information • Varies depending on network class and the way subnetting is used • LAN subnetting – LAN’s devices interpret device subnetting information – External routers • Need network portion of device IP address Network+ Guide to Networks, 5 th Edition 83
Figure 10-3 A router connecting several subnets Network+ Guide to Networks, 5 th Edition 84
Activity on Classless IP addressing
• Imagine you are the Network administrator in an organization and you have 2 Departments and each department has a maximum of 60 computers what would be the range of IP addresses that could be used for each subnetwork and what would be its corresponding subnet mask?
• Refer to slide 80-84 as reference for your format for your answer.
85
CIDR (Classless Interdomain Routing)
• Also called classless routing or supernetting • Not exclusive of subnetting – Provides additional ways of arranging network and host information in an IP address – Conventional network class distinctions do not exist • Example: subdividing Class C network into six subnets of 30 addressable hosts each • Supernet – Subnet created by moving subnet boundary left Network+ Guide to Networks, 5 th Edition 86
CIDR (cont’d.)
Figure 10-4 Subnet mask and supernet mask Network+ Guide to Networks, 5 th Edition 87
CIDR (cont’d.)
Figure 10 5 Calculating a host’s network ID on a supernetted network • Example: class C range of IPv4 addresses sharing network ID 199.34.89.0
– Need to greatly increase number of default host addresses Network+ Guide to Networks, 5 th Edition 88
CIDR (cont’d.)
• CIDR notation (or slash notation) – Shorthand denoting subnet boundary position – Form • Network ID followed by forward slash ( / ), followed by number of bits used for extended network prefix – CIDR block • Forward slash, plus number of bits used for extended network prefix Network+ Guide to Networks, 5 th Edition 89
Class C CIDR Block
/21 /22 /23 /24 /14 /15 /16 /17 /18 /19 /20 /25 /26 /27 /28 /29 /30
Slash Notation in CIDR
Binary Supernet Mask
11111111.11111100.00000000.00000000
11111111.11111110.00000000.00000000
11111111.11111111.00000000.00000000
11111111.11111111.10000000.00000000
11111111.11111111.11000000.00000000
11111111.11111111.11100000.00000000
11111111.11111111.11110000.00000000
11111111.11111111.11111000.00000000
11111111.11111111.11111100.00000000
11111111.11111111.11111110.00000000
11111111.11111111.11111111.00000000
11111111.11111111.11111111.10000000
11111111.11111111.11111111.11000000
11111111.11111111.11111111.11100000
11111111.11111111.11111111.11110000
11111111.11111111.11111111.11111000
11111111.11111111.11111111.11111100
Supernet Mask
255.252.0.0
255.254.0.0
255.255.0.0
255.255.128.0
255.255.192.0
255.255.224.0
255.255.240.0
255.255.248.0
255.255.252.0
255.255.254.0
255.255.255.0
255.255.255.128
255.255.255.192
255.255.255.224
255.255.255.240
255.255.255.248
255.255.255.252
Number of Class C Networks
8 4 2 1 1024 512 256 128 64 32 16 1/2
Number of Hosts
262144 131072 65536 32768 16384 8192 4096 2048 1024 512 254 126 1/4 1/8 62 32 1/16 1/32 1/64 16 8 90 4
Understanding IP Addresses and How They Are Used (cont’d.)
• Dynamic IP address – Assigned for current connection only (lease) – Managed by DHCP server • DHCP client: workstations working with DHCP server • DHCP software resides client and server • Configuring a DHCP server – IP address ranges available for clients • Automatic Private IP Address (APIPA) service – Used if attempt fails • Address range 169.254.x.y
A+ Guide to Managing and Maintaining Your PC, 7e 91
Summary
• A network is a system interconnecting two or more PCs – Basic network types • PAN, LAN, Wireless LAN, MAN, or WAN • There are many broadband technologies – Cable and DSL popular • Major issue for wireless networks is security • Types of hardware – Adapters, routers, hubs, switches A+ Guide to Managing and Maintaining Your PC, 7e 92
Summary (cont’d.)
• Three layers of communication – Hardware, operating system, application • An IP address is a 32-bit address identifying network node • TCP/IP protocol suite uses protocols at the application level • Connecting to a wired network • Connecting to a wireless networks – Public, unsecured hotspots or private, secured hotspots A+ Guide to Managing and Maintaining Your PC, 7e 93