NETWORKING REVIEWER.pdf

OA kong reviewer NETWORKING REVIEWER Black Hat - bad hacker Gray Hat - in between Lesson 1 Networking Pathway Introduction to System and...

OA kong reviewer NETWORKING REVIEWER Black Hat - bad hacker Gray Hat - in between Lesson 1 Networking Pathway Introduction to System and Network 1. Network Architect Administration 2. Network Engineer 3. Cloud Engineer Information Technology - Refers to the use of 4. Database Administrator computers, software, networks, and other 5. Security Specialist technologies to store, retrieve, transmit, and 6. Telecommunication Specialist manipulate data and information. IT encompasses a wide range of technologies and Network Administration practices that enable individuals and organizations - Branch of engineering that concerns the to manage and process data effectively. operational management of human - computer systems. The development, implementation, and Responsibilities of Network Administrator maintenance of computer hardware and software 1. Designing the Network systems to organize and communicate information 2. Setting Up the Network electronically. 3. Maintaining the Network 4. Expanding the Network Designing the Network 1. Budget 2. Type of Traffic ➔ Data (TCP/IP) ➔ Voice (UDP) Telephone Line ➔ Video (UDP) Live video with no playback 3. Number of Users 4. Compatibility TCP/IP - Transmission control protocol UDP - User datagram protocol Career Path CCST (Networking) Cisco Certified Support Overview of needs as an Network Admin - Goal: Technology Infrastructure and systems 100% operational ❖ Fundamentals of Networking ❖ Initial of devices and configuration Possible Type of Errors ❖ Network security ★ Hardware Failure ❖ IP addressing ★ Application / Problem Errors CCNA - Cisco Certified Network Association ★ Data Corruption ❖ CCNP (Cisco Certified Network ★ Power Outage Professional) → CCIE ★ Security Concern ❖ Cybersecurity ❖ RHCE (Red Hot Certified Expert) Type of Administrator 1. Database Administrator - Responsible for 3 types of Hackers the integrity of the data and the efficiency of White Hat - good hacker the Database System. OA kong reviewer 2. Network Administrator - Maintain network Management Forum divided network infrastructure and diagnose problems with management into five functional areas (FCAPS): the behavior of network attached computers. 1. Forum Management - process of locating 3. Security Administrator - Specialist in problems computer and network security, including ➔ Discover the problem the administration of security devices such ➔ Isolate the problem as firewalls, as well as consulting on ➔ Fix/replace the problem general security measures. 2. Configuration Management - The 4. Web Administrator - managing multiple configuration of certain network devices sites, security, and configuring necessary controls the behavior of the data network. components and software. Responsibilities ➔ Configuration management is the may also include software change process of finding and setting up management (configuring) these critical devices 5. Technical Support - Respond to individual users difficulties with computer systems, 3. Accountating Management - Involves provide instructions and sometimes training, tracking individual’s utilization and grouping and diagnose and solve common problems. of network resources to ensure that users have sufficient resources. What does a Network Administrator do? ➔ Involves granting or removing 1. Deployment, configuration, maintenance permission to access the network and monitoring of active network equipment 4. Performance Management - Measuring 2. Overall health of network the performance of the network hardware, 3. Maintenance of network facilities software, and media. 4. Maintenance of network server Overall throughput 5. Keeping the organization connected Percentage utilization 6. Upgrade and installs Error rates 7. Troubleshooting Response time 8. Patching Systems 5. Security Management 9. Monitoring for possible problems Controlling access to information on 10. Documentation the data network 11. Adding and Deleting Network Users To monitoring access points and records information Network Management Audit trails and sounds alarm for Network management is the process of security strategy controlling a complex data network to maximize its efficiency and productivity. Challenge of Administration The overall goal of network management is to Design logical, efficient networks help with the complexity of a data network and to Easily deploy and update many machines ensure that data can go across it with maximum Decide what services are needed or know efficiency and transparency to the users. the business tasks and customers Plan and implements adequate security Division of Labor Be able to fix errors and problems Network Keep track and be able to use knowledge Hardwok Application Style of Network Administration ISO Network Management forum network Fire-fighting - Managing by responding to OA kong reviewer situations that may happen. Sharing hardware - e.g. print document Centralized administration and support 1. Investigate the Fault or Problem a. Isolate the problem and identify/Define it Advantages of Networking b. Use tests and tools to diagnose the Connectivity and communication problem Data sharing c. Solve the problem and document Hardware Sharing the solution Internet access Internet access sharing 2. Prioritize multiple problems Data and security and management Performance enhancement and balancing Preventive Management - Monitor networks and Entertainment make repairs and changes before problem appears (proactive) Disadvantages (costs) of Networking Capacity Planning Network hardware, software and setup Simulation and Testing costs Load Generators Hardware and software management and Benchmarks administration costs Undesirable sharing Performance Monitors and System Data security and concerns Tuning Network Analysis and modelling Networking Terminology Load Balancing Lan (Local Area of Network) - Networks Hardware Upgrades are often called LANs. On the Network - computer that's on the network. Good Management Cycle Online, Offline - can access the network, can't access the network.. Binary Number Systems Up, down - Up - computer is turned on and Bits - 1 and 0 working properly. Down - turned off, broken, Byte - Equivalent of 8 bits or at service is down. Local, remote - local - resides in your Bits → Byte → Kilobyte → Megabyte → Gigabyte computer. Remote - resides in other → Terabyte computer.Internet, Intranet - internet - world wide, Lesson 2 public network. Intranet - private network that is contained within an enterprise. Introduction To Networking Understanding the Network What is Networking Network Structure ➔ Consist of 2 or more computers connected Node - anything connected to the network. together, and they can communicate and Segment - any portion of a network that is share resources separated by switch, bridge or router from another part of the network. Why Networking Backbone - main cabling of a network. Sharing information - If data communicate Topology - the way each node is physically OA kong reviewer connected to the network. Support more users – difficult to Physical Topology- describe how the achieve with peer-to-peer networks cables are run. Disadvantages of client/server networks Is the complete physical structure of the High cost for Servers transmission media. Need expert to configure the Logical Topology - Logical topologies network describe how the network messages travel. Local Area Network (LAN) Small network, short distance Clients and Servers A room, a floor, a building Network Clients (Workstation) Limited by no. of computers ➔ Computers that request network resources and distance covered or services Usually one kind of Network Servers technology throughout the LAN ➔ Computers that manage and provide network resources and services to clients Serve a department within an ◆ Usually have more processing organization power, memory and hard disk space Examples: than clients Network inside a Computer ◆ Run Network Operating System that Laboratory can manage not only data, but also users, security, and applications on Network inside your home the network Network inside your office ◆ Servers often have a more stringent requirement on its performance and reliability Wide Area Network ➔ A network that uses long-range Peer-to-Peer Networks telecommunication links to connect 2 or ➔ Peer-to-peer network is also called more LANs/computers housed in different workgroup places far apart. ➔ No hierarchy among computers ⇒ all are ➔ Towns, states, countries equal ➔ No administrator responsible for the Metropolitan Area network network ◆ is a network that interconnects users with computer resources in a Advantages of peer-to-peer networks: geographic area or region larger ◆ Low cost than that covered by even a large ◆ Simple to configure local area network (LAN) but ◆ User has full accessibility of the smaller than the area covered by a computer wide area network (WAN). Pan - Personal Area Network Disadvantages of peer-to-peer networks: ➔ Is a computer network for interconnecting ◆ Difficult to uphold security policy devices centered on an individual person's ◆ Difficult to handle uneven loading workplace. SAN - Storage Area Network Advantages of client/server networks ➔ Is a specialized high speed network that Facilitate resource sharing – provides block level network access to centrally administrate and control storage. Facilitate system backup and improve fault tolerance WLAN - Wireless LAN Enhance security – only ➔ Is a wireless computer network that links administrator can have access to Server two or more devices using wireless OA kong reviewer communication from a local area network single cable, fault isolation is (lan) wthin a limited area such as home, relatively difficult. school, computer, laboratory, campus, Units affected by media failure office, building etc. Bus cable faults or breaks stop all communications. Every device Connection TYpes receives excessive noise (due to signal reflection) POINT-TO-POINT ➔ Is a direct link between two devices. Eg., RING - circular topology (or closed loop of computer to printer, pc to pc, microwave to point-to-point). Each node is connected to the two antennas. nearest nodes so the entire network forms a circle Ease of Installation MULTIPOINT ➔ Also called mutidrop is a link between three At initial installation, it is moderately simple to install or more devices. Ease of Reconfiguration Network Topologies Ring networks become harder to reconfigure as the A topology is a way of “laying out” the scale of relocations increases. Ring segments must network. Topologies can be either physical be divided or replaced with two new segments each or logical. time a segment is changed. Physical topologies describe how the cables are Ease of Troubleshooting run. ➔ Is the complete physical structure of the Because each device incorporates a repeater, you transmission media. can easily find cable faults. Units affected by Media failure Topologies Characteristics/Consideration Most rings use only one loop, Faults in single loop systems affects most devices on the network. 1. Relative ease of installation 2. Relative ease of reconfiguration STAR - uses a central device with drop cables 3. Relative ease of troubleshooting extending in all directions. Each network device is 4. Maximum number of units affected by a connected via point to point link to the central media failure. device. 5. Logical topologies describe how the network Ease of Installation messages travel. Are moderately difficult to install. The design of the network is simple, but you must install a separate media BUS - typically uses long cable, called backbone, segment for every arm of the star. short cables called drop cables. Ease of Installation Ease of Reconfiguration Relatively easy to install, simply string Are relatively easy to reconfigure. the backbone cable from site to Moves, adds, and changes do not site. involve more than the connection Ease of Reconfiguration between changed networked device. Because most bus topologies are laid out to minimize the required Ease of Troubleshooting amount of cable, reconfiguration Easy to troubleshoot. It can also be tends to be moderately difficult. organized hierarchically, providing Ease of Troubleshooting architectural flexibility and traffic When troubleshooting media, you isolation isolate the fault to a specific media Units affected by Media failure segment. Because it is based on a OA kong reviewer It handles media faults relatively well. If relocation is relatively simple a media fault occurs on the network, you can use the NETWORK BACKBONE hub/switch to identify and remove offending link from the network. Serial Backbone Daisy chain: linked series of devices MESH - has a high point connections between every device in the network together with another ○ Hubs and switches often connected in daisy chain to extend a network topology. (mixed). Because each devices requires interface for every device, it is not considered Hubs, gateways, routers, switches, and practical. bridges can form part of backbone Ease of Installation Extent to which hubs can be connected is limited Difficult to install because each device must be linked directly to all other device Distributed Backbone Ease of Reconfiguration is a backbone network that consists of a number of connectivity devices connected Difficult to reconfigure. Same reason as above. to a series of central connectivity devices, such as hubs, switches, or routers Ease of Troubleshooting Easy to troubleshoot because each Collapsed Backbone medium link is independent of all others A network configuration that provides a backbone in a centralized location, to which Units affected by Media failure all subnetworks are attached. Resist media failures better than other topologies. Parallel Backbone Each switch and router are connected by CELLULAR/WIRELESS - combines wireless point two cables. By having more than one cable to point and multi point strategies to divide a connecting each device, it ensures network geographic area into cells. Devices within the cell connectivity to any area of the communicate with a central station. It relies on the enterprise-wide network location of the wireless media hub. OSI AND TC/IP LAYER Ease of Installation Dependent upon the accessibility of Introduction OSI hub locations. If desirable hub locations are available, installation The Open System Interconnection is relatively easy. If not, you must Reference Model (OSI Reference Model or arrange property easement. OSI Model) is a description for layered Ease of Reconfiguration communications and computer network Because it does not require cable, it protocol & transmission design. does not require reconfiguration as It divides data movement into seven layers users move. which, from top to bottom, are the Ease of Troubleshooting Application, Presentation, Session, Relatively simple because each hub Transport, Network, Data Link, and Physical interacts independently with each Layers. It is therefore often referred to as device. the OSI Seven Layer Model. Units affected by Media failure OSI History When portion of it fail, all the units in the cell’s assignment range are affected. However, because they In 1978, the International Standards are allowed to roam, temporary Organization (ISO) began to develop its OSI framework architecture. OA kong reviewer The concept of a 7 layer model was Layer 2: Data Link Layer provided by the work of Charles Bachman, then of Honeywell. The Data Link Layer provides the functional Various aspects of OSI design evolved from and procedural means to transfer data experiences with the Advanced Research Projects Agency Network (ARPANET) and between network entities and to detect and the fledgling Internet possibly correct errors that may occur in the Physical Layer. MAC Address is used at this layer. Switches function at this layer. OSI Model Layer 3: Network Layer Data Layer Function The Network Layer provides the functional unit and procedural means of transferring data Network process to from a source to a destination via one or 7. Application application more networks. The Network Layer performs ◦ network routing functions, Data representation, 6. Presentatio Routers operate at this layer—sending data Data encryption and n throughout the extended network and Host decryption layer making the Internet possible. s Interhost 5. Session communication Layer 4: Transport Layer Seg End-to-end The Transport Layer provides transparent transfer ment 4. Transport connections and of data between end users, providing reliable data s reliability, Flow contr transfer services to the upper layers. The Transport Layer controls the reliability of a Pack Path determination given link through flow control, 3. Network et and logical addressin segmentation/desegmentation, and error control. Medi a Fram Layer 5: Session Layer 2. Data Link Physical addressing layer e The Session Layer controls the dialogues s (connections) between computers. Media, signal and It establishes, manages and terminates the Bit 1. Physical binary transmission connections between the local and remote application. Layer 6: Presentation Layer Layer1: Physical Layer The Presentation Layer establishes a The Physical Layer defines the electrical context between Application Layer entities, and physical specifications for devices. In in which the higher-layer entities can use particular, it defines the relationship different syntax and semantics, as long as between a device and a physical medium. the presentation service understands both This includes the layout of pin, voltages, and the mapping between them. This layer cable specification, hubs, repeaters, provides independence from differences in network adapters, host bus adapters, and data representation (e.g., encryption) by more. 0’s and 1’s. translating from application to network The major functions and services performed format, and vice versa. by the Physical Layer are: This layer formats and encrypts data to be ❖ Establishment and termination of a sent across a network, providing freedom connection to a communication medium. from compatibility problems. ❖ Singles being sent and received 0’s and 1’s. OA kong reviewer It is sometimes called the syntax layer. Internet Layer Network Layer IP , ICMP, ARP, RARP,... Layer 7: Application Layer The application layer is the OSI layer Data Link Layer Link Layer closest to the end user, which means that FDDI, Ethernet, ISDN, both the OSI application layer and the user Physical Layer X.25,... interact directly with the software application. Application layer functions typically include: identifying communication partners, determining resource availability, Layer Protocol Some examples of application layer DNS, TFTP, TLS/SSL, FTP, Gopher, HTTP, I implementations include MAP, IRC, NNTP, POP3, SIP, SMTP, SMPP, Hypertext Transfer Protocol (HTTP) SNMP, SSH, Telnet, Echo, RTP, PNRP, rlogin File Transfer Protocol (FTP) Applic , ENRP ation Simple Mail Transfer Protocol (SMTP) Routing protocols like BGP and RIP which run over TCP/UDP, may also be considered part Introduction TCP/IP of the Internet Layer. Transp The Internet Protocol Suite (commonly TCP, UDP, DCCP, SCTP, IL, RUDP, RSVP ort known as TCP/IP) is the set of communications protocols used for the IP (IPv4, IPv6), ICMP, IGMP, and ICMPv6 Internet and other similar networks. It is named from two of the most important Interne protocols in it: t OSPF for IPv4 was initially considered IP the Transmission Control Protocol (TCP) layer protocol since it runs per IP-subnet, but and has been placed on the Link since RFC 2740. the Internet Protocol (IP), which were the first two networking protocols defined in this Link ARP, RARP, OSPF (IPv4/IPv6), IS-IS, NDP standard. TC/IP LAYERS Lesson 3 What is a packet? OSI TCP/IP It turns out that everything you do on the Internet/network involves packets. Application Layer For example, every Web page that you Application Layer receive comes as a series of packets, and TELNET, FTP, SMTP, every e-mail you send leaves as a series of Presentation Layer POP3, SNMP, NNTP, packets DNS,NIS, NFS, HTTP,. Session Layer Transport Layer Transport Layer TCP , UDP ,... Media Access Control - MAC Addresses ➔ are physical addresses, unlike IP addresses OA kong reviewer which are logical addresses. Unicast ➔ Logical addresses require you to load ➔ Unicast is very simple and one of the most special drivers and protocols in order to be common data transmissions in a network able to configure your network ➔ Data is transferred between these two card/computer with an IP Address, whereas hosts only, where as a broadcast or a a MAC address doesn't require any drivers multicast is destined either everyone or just whatsoever. The reason for this is that the a group of computers. MAC address is actually "burnt-in" into your Multicast network card's memory chipset. ➔ A multicast is similar to a broadcast in the sense that its target is a number of machines on a network, but not all. Where a broadcast is directed to all hosts on the network, a multicast is directed to a group of hosts Broadcast ➔ The term "Broadcast" is used very frequently in the networking world ➔ A Broadcast means that the network MAC Addresses are always presented in HEX delivers one copy of a packet to each format, just as our example above destination. Parts of the MAC Address INTRODUCTION TO THE INTERNET AND WEB IEEE (Institute of Electrical & Electronics INTERNET Engineers) group split the MAC address in It is the largest network in the world that half, and used the first half to identify the connects hundreds of thousands of vendor, and the second half is for the individual networks all over the world. vendor to allocate as serial numbers The popular term for the Internet is the The Vendor code is specified by RFC - “information highway”. 1700. Rather than moving through geographical the MAC address is "burnt-in" to the space, it moves your ideas and information network card's memory through cyberspace – the space of electronic movement of ideas and information. No one owns it It has no formal management organization. To access the Internet, an existing network need to pay a small registration fee and agree to certain standards based on the TCP/IP (Transmission Control NETWORK DATA TRANSMISSION Protocol/Internet Protocol). Routable protocols enable the transmission of data between computers in different THE USES OF INTERNET segments of a network. However, high Send e-mail messages. volumes of certain kinds of network traffic Send (upload) or receive (down load) files can affect network efficiency because they between computers. slow down transmission speed. Participate in discussion groups, such as 3 TYPES OF NETWORK DATA TRANSMISSION mailing lists and newsgroups. OA kong reviewer Surfing the web. Web is a collection of files that reside on computers, called Web servers, that are WHAT IS WEB? located all over the world and are connected The Web (World Wide Web) consists of to each other through the Internet. information organized into Web pages When you use your Internet connection to containing text and graphic images. become part of the Web, your computer It contains hypertext links, or highlighted becomes a Web client in a worldwide keywords and images that lead to related client/server network. information. A Web browser is the software that you run A collection of linked Web pages that has a on your computer to make it work as a web common theme or focus is called a Web client. site. The main page that all of the pages on a HYPERTEXT MARKUP LANGUAGE (HTML) particular Web site are organized around and link back to is called the site’s home The public files on the web servers are page. ordinary text files, much like the files used by word-processing software. HOW TO ACCESS THE INTERNET To allow Web browser software to read them, the text must be formatted according Many schools and businesses have direct to a generally accepted standard. access to the Internet using special The standard used on the web is Hypertext high-speed communication lines and markup language (HTML). equipment. HTML uses codes, or tags, to tell the Web Students and employees can access browser software how to display the text through the organization’s local area contained in the document. ⦿ networks (LAN) or through their own For example, a Web browser reading the personal computers. following line of text: A Review of the Another way to access the Internet is BookWind Instruments of the 18th through Internet Service Provider (ISP). Century recognizes the and tags as instructions to INTERNET SERVICE PROVIDER (ISP) display the entire line of text in bold and the A commercial organization with permanent and tags as instructions to display the text connection to the Internet that sells enclosed by those tags in italics. temporary connections to subscribers. Examples: PLDT MyDSL, BayanDSL, ADDRESSES ON THE WEB;IP ADDRESSING SmartBrodband etc. Each computer on the internet does have a HOW TO ACCESS THE WEB unique identification number, called an IP Once you have your Internet connection, (Internet Protocol) address. then you need special software called a The IP addressing system currently in use browser to access the Web. on the Internet uses a four-part number. Web browsers are used to connect you to Each part of the address is a number remote computers, open and transfer files, ranging from 0 to 255, and each part is display text and images. separated from the previous part by period, Web browsers are specialized programs. For example, 106.29.242.17 Examples of Web browser: Netscape Navigator (Navigator) and Internet Explorer IP ADDRESSING The combination of the four IP address CLIENT/SERVER STRUCTURE OF THE WEB parts provides 4.2 billion possible addresses OA kong reviewer (256 x 256 x 256 x 256). computer. This number seemed adequate until 1998. To identify a Web pages exact location, Web Members of various Internet task forces are browsers rely on Uniform Resource Locator working to develop an alternate addressing (URL). system that will accommodate the projected URL is a four-part addressing scheme that growth. tells the Web browser: However, all of their working solutions ➔ What transfer protocol to use for require extensive hardware and software transporting the file changes throughout the Internet. ➔ The domain name of the computer on which DOMAIN NAME ADDRESSING the file resides Most web browsers do not use the IP ➔ The pathname of the folder or directory on address t locate Web sites and individual the computer on which the file resides pages. ➔ The name of the They use domain name addressing. A domain name is a unique name associated with a specific IP address by a program that runs on an Internet host computer. This program, which coordinates the IP addresses and domain names for all computers attached to it, is called DNS (Domain Name System ) software. The host computer that runs this software is HTTP called a domain name server. Domain names can include any number of The transfer protocol is the set of rules that parts separated by periods, however most the computers use to move files from one domain names currently in use have only computer to another on the Internet. three or four parts. The most common transfer protocol used on Domain names follow hierarchical model the Internet is the Hypertext Transfer that you can follow from top to bottom if you Protocol (HTTP). read the name from the right to the left. Two other protocols that you can use on the For example, the domain name Internet are the File Transfer Protocol (FTP) valenzuela.deped.gov.ph is the computer and the Telnet Protocol connected to the Internet at valenzuela (valenzuela), which is a division of the HOW TO FIND INFORMATION ON THE WEB Department of Education (deped), which is A number of search tools have been government institution (gov) in the developed and available to you on certain Philippines (ph). Web sites that provide search services to No other computer on the Internet has the help you find information. same domain name. Examples ➔ Yahoo - www.yahoo.com UNIFORM RESOURCE LOCATORS ➔ Excite - www.excite.com ➔ Lycos- www.lycos.com The IP address and the domain name each ➔ AltaVista - www/alta-vista.com identify a particular computer on the ➔ MSN WebSearch - www.search.ms Internet. You can find information by two basic However, they do not indicate where a Web means. page’s HTML document resides on that Search by Topic and Search by keywords. OA kong reviewer Some search services offer both methods, designate a specific network or host. others only one. - This section of the IP address is typically Yahoo offers both. found towards the beginning of an IP ➔ Search by Topic address. ➔ You can navigate through topic lists ➔ Search by keywords Host ID ➔ You can navigate by entering a keyword or - Another portion of an IP address used to phase into a search text box. identify a specific IP/TCP network. - A host ID is found after a network ID and Lesson 4 can be used in conjunction with class identifier and to create default subnet masks Ipv4 as needed. An IPv4 address is 32-bit hierarchical address that is made up of a network Class Range Portion Subnet Mask portion and a host portion. The bits within the network portion of the A 0 - 127 N. H. H. H 255.0.0.0 address must be identical for all devices that reside in the same network. If two hosts B 128 - 191 N. N. H. H 255.255.0.0 have the same bit-pattern in the specified C 192 - 223 N. N. N. H 255.255.255.0 network portion of the 32-bit stream, those two hosts will reside ib the same network. D 224 - 239 Experimental Experimental IP Address E 240 - 255 Experimental Experimental An IP address is an address having information about how to reach a specific Range of Special IP Addresses host, especially outside the LAN. An IP address is a 32-bit unique address - 168.255.0.0 - 169.254.0.16: APIPA having an address space od 2^32. (Automatic Private IP address) Two notations in which IP address is written: - 127.0.0.0. - 127.0.0.8: Loop-back ○ Dotted Decimal Notation addresses 1. The value of any segment - 0.0.0.0 - 0.0.0.8: used to communicate (byte) is between 0 and 255 within the current network. (both included). 2. No zeroes are preceding the Rules for Assigning Host ID value in any segment (054 is - Host IDs are used to identify a host within a wring. 54 is correct). network. - The host ID is assigned based on the Classful Addressing following rules: Class A Within any network, the host ID must Class B be unique to that network. Class C A host ID in which all bits are set to Class D 0 cannot be assigned because this Class E host ID is used to represent the network ID of the IP address. IPv4 address is divided into two parts: Host ID in which all bits are set to 1 cannot be assigned because this Network ID host ID is reserved as a broadcast - A portion of an IP address that is used to address to send packets to all the OA kong reviewer hosts present on that particular 4. Select Network Adapter and right click network. 5. Click ‘Properties’ - Hosts that are located on the same physical 6. Find Internet Protocol Version 4 (TCP/IPv4) network are identified by the network ID, as all host on the same physical network are Note that the subnet mask does not actually assigned the same network ID. The network contain the network or host portion of an IPv4 ID is assigned based on the following rules: address, it just tells the computer where to look for The network ID cannot start with 127 the part of the IPv4 address that is the network because 127 belongs to the class A portion and which part is the host portion. address and is reserved for internal loopback functions. All bits of network ID set to 0 are used to denote a specific host on the local network and are not routed and therefore, aren’t used. SUBNET MASK Notice how the subnet mask is a consecutive sequence of 1 bits followed by a consecutive sequence of 0 bits. To identify the network and host portions of an IPv4 address, the subnet mask is compared to the IPv4 address bit for bit, from left to right as shown in the figure. Associating an IPv4 Address with its Subnet Mask PHYSICAL LAYER OF OSI LAYERS (CABLES AND SIGNALS) Physical Layer Subnet Mask - The protocols and operations of the upper Assigning an IPv4 address to a host requires OSI layers are performed using software the following: designed by software engineers and - IPv4 address - This is the unique IPv4 computer scientists. The services and address of the host. protocols in the TCP/IP suite are defined by - Subnet mask- This is used to identify the the Internet Engineering Task Force (IETF). network/host portion of the IPv4 address. - The physical layer consists of electronic circuitry, media, and connectors developed IPv4 Configuration on a Windows Computer by engineers. 1. Click windows button. - The physical layer hardware, media, 2. Search Network Settings encoding, and signaling standards are 3. Find change adapter options defined and governed by these standards OA kong reviewer organizations: dashes. ✔ International Organization for Standardization (ISO) ★ Signaling ✔ American National Standards - The physical layer must generate the Institute (ANSI)/Telecommunications electrical, optical, or wireless signals that Industry Association (TIA) represent the "1" and "0" on the media. The ✔ International Telecommunication way that bits are represented is called the Union (ITU) signaling method. ✔ Institute of Electrical and - The physical layer standards must define Electronics Engineers (IEEE) what type of signal represents a "1" and ✔ National telecommunications what type of signal represents a "0". This regulatory authorities including the can be as simple as a change in the level of Federal Communication an electrical signal or optical pulse. Commission (FCC) in the USA and - For example, a long pulse might represent a the European Telecommunications 1 whereas a short pulse might represent a Standards Institute (ETSI) 0. - This is similar to the signaling method used The physical layer standards address three in Morse code, which may use a series of functional areas: on-off tones, lights, or clicks to send text Physical Components over telephone wires. Encoding Signaling NETWORK SPEED TERMINOLOGY ★ Physical Components Terms used to measure the quality of - The physical components are the electronic bandwidth include: hardware devices, media, and other Bandwidth connectors that transmit the signals that Throughput represent the bits. Latency - Hardware components such as NICs, interfaces and connectors, cable materials, ★ BANDWIDTH and cable designs are all specified in - Amount of data that can be transmitted and standards associated with the physical received during a specific period of time, layer. measured in bits per second. - The various ports and interfaces on a Cisco - Theoretical Maximum Speed 1941 router are also examples of physical - Data transfer is usually discussed in terms components. of bandwidth. - Bandwidth is the capacity at which a ★ Encoding medium can carry data. - Encoding or line encoding is a method of - Digital bandwidth measures the amount of converting a stream of data bits into a data that can flow from one place to another predefined "code". Codes are groupings of in a given amount of time. bits used to provide a predictable pattern - Bandwidth is typically measured in kilobits that can be recognized by both the sender per second (kbps), megabits per second and the receiver. (Mbps), or gigabits per second (Gbps). - In other words, encoding is the method or - Bandwidth is sometimes thought of as the pattern used to represent digital information. speed that bits travel, however this is not - This is similar to how Morse code encodes accurate. a message using a series of dots and OA kong reviewer ★ THROUGHPUT 1. Electromagnetic interference (EMI) or - Throughput is the measure of the transfer of radio frequency interference (RFI) - EMI bits across the media over a given period of and RFI signals can distort and corrupt the time. Due to a number of factors, throughput data signals being carried by copper media. usually does not match the specified Potential sources of EMI and RFI include bandwidth in physical layer radio waves and electromagnetic devices, implementations. such as fluorescent lights or electric motors. - Actual Speed 2. Crosstalk - Crosstalk is a disturbance - Throughput is usually lower than the caused by the electric or magnetic fields of bandwidth. a signal on one wire to the signal in an adjacent wire. In telephone circuits, ★ LATENCY crosstalk can result in hearing part of - Latency refers to the amount of time, another voice conversation from an including delays, for data to travel from one adjacent circuit. given point to another. - Network Delay which is measured in - To counter the negative effects of EMI and milliseconds, total roundtrip time. RFI, some types of copper cables are - In an internetwork, or a network with wrapped in metallic shielding and require multiple segments, throughput cannot be proper grounding connections. faster than the slowest link in the path from - To counter the negative effects of crosstalk, source to destination. some types of copper cables have opposing circuit wire pairs twisted together, which effectively cancels the crosstalk. COPPER CABLING Types of Copper Cabling: Characteristics of Copper Cabling - Copper cabling is the most common type of 3 Main types of copper media used in networking: cabling used in networks today. In fact, copper cabling is not just one type of cable. There are three different types of copper cabling that are each used in specific situations. - Networks use copper media because it is inexpensive, easy to install, and has low resistance to electrical current. However, copper media is limited by distance and signal interference. Data is transmitted on copper cables as electrical pulses. - A detector in the network interface of a destination device must receive a signal that can be successfully decoded to match the signal sent. However, the farther the signal travels, the more it deteriorates. This is Unshielded Twisted Pair referred to as signal attenuation. ★ Unshielded twisted-pair (UTP) cabling is the most common networking media. UTP - The timing and voltage values of the cabling, terminated with RJ-45 connectors, electrical pulses are also susceptible to is used for interconnecting network hosts interference from two sources: with intermediary networking devices, such OA kong reviewer as switches and routers. name from the fact that there are two ★ In LANs, UTP cable consists of four pairs of conductors that share the same axis. As color-coded wires that have been twisted shown in the figure, coaxial cable consists together and then encased in a flexible of the following: plastic sheath that protects the wires from ★ A copper conductor is used to transmit the minor physical damage. The twisting of electronic signals. wires helps protect against signal ★ A layer of flexible plastic insulation interference from other wires. surrounds a copper conductor. The numbers in the figure identify some key ★ The insulating material is surrounded in a characteristics of unshielded twisted pair woven copper braid, or metallic foil, that cable: acts as the second wire in the circuit and as The outer jacket protects the copper wires a shield for the inner conductor. This second from physical damage. layer, or shield, also reduces the amount of Twisted-pairs protect the signal from outside electromagnetic interference. interference. ★ The entire cable is covered with a cable jacket to prevent minor physical damage. Color-coded plastic insulation electrically ➔ There are different types of connectors used isolates wires from each other and identifies with coax cable. The Bayonet each pair Neill–Concelman (BNC), N type, and F type connectors are shown in the figure. Shielded Twisted Pair ➔ Although UTP cable has essentially ★ Shielded twisted-pair (STP) provides better replaced coaxial cable in modern Ethernet noise protection than UTP cabling. installations, the coaxial cable design is However, compared to UTP cable, STP used in the following situations: cable is significantly more expensive and ➔ Wireless installations - Coaxial cables difficult to install. Like UTP cable, STP uses attach antennas to wireless devices. The an RJ-45 connector. coaxial cable carries radio frequency (RF) ★ STP cables combine the techniques of energy between the antennas and the radio shielding to counter EMI and RFI, and wire equipment. Cable internet installations - twisting to counter crosstalk. To gain the full Cable service providers provide internet benefit of the shielding, STP cables are connectivity to their customers by replacing terminated with special shielded STP data portions of the coaxial cable and supporting connectors. If the cable is improperly amplification elements with fiber-optic cable. grounded, the shield may act as an antenna However, the wiring inside the customer's and pick up unwanted signals. premises is still coax cable. The STP cable shown uses four pairs of wires, each wrapped in a foil shield, which The numbers in the figure identify some key are then wrapped in an overall metallic braid features of coaxial cable: or foil. The numbers in the figure identify some key Outer jacket features of shielded twisted pair cable: Braided copper shielding Outer jacket Plastic insulation Braided or foil shield Copper conductor Foil shields Twisted pairs Coaxial Cable ★ Coaxial cable, or coax for short, gets its OA kong reviewer ➔ MMF consists of a larger core and uses LED emitters to send light pulses. Specifically, light from an LED enters the multimode fiber at different angles, as shown in the figure. MMFs are popular in LANs because they can be powered by low-cost LEDs. It provides bandwidth up to 10 Gbps over link lengths of up to 550 meters. SMF VS MMF ➔ One of the highlighted differences between MMF and SMF is the amount of dispersion. Dispersion refers to the spreading out of a Fiber Optic Cabling light pulse over time. Increased dispersion means increased loss of signal strength. ➔ Optical fiber cable transmits data over MMF has a greater dispersion than SMF. longer distances and at higher bandwidths That is why MMF can only travel up to 500 than any other networking media. Unlike meters before signal loss copper wires, fiber-optic cable can transmit signals with less attenuation and is Fiber-Optic Cabling Usage completely immune to EMI and RFI. Optical fiber is commonly used to interconnect Fiber-optic cabling is now being used in four types network devices. of industry: ➔ Optical fiber is a flexible, but extremely thin, ➔ Enterprise Networks - This is used for transparent strand of very pure glass, not backbone cabling applications and much bigger than a human hair. Bits are interconnecting infrastructure devices. encoded on the fiber as light impulses. The ➔ Fiber-to-the-Home (FTTH) - This is used to fiber-optic cable acts as a waveguide, or provide always-on broadband services to “light pipe,” to transmit light between the two homes and small businesses. ends with minimal loss of signal. ➔ Long-Haul Networks - This is used by service providers to connect countries and Types of Fiber Optic cable cities. ➔ Submarine Cable Networks - This is used Fiber-optic cables are broadly classified into two to provide reliable high-speed, high-capacity types: solutions capable of surviving in harsh undersea environments at up to Single-mode fiber (SMF) transoceanic distances. Search the internet ➔ SMF consists of a very small core and uses for “submarine cables telegeography map” expensive laser technology to send a single to view various maps online. Our focus in ray of light, as shown in the figure. SMF is this course is the use of fiber within the popular in long-distance situations spanning enterprise. hundreds of kilometers, such as those required in long haul telephony and cable Fiber-Optic Connectors TV applications. ➔ An optical-fiber connector terminates the end of an optical fiber. A variety of Multimode fiber (MMF) optical-fiber connectors are available. The OA kong reviewer main differences among the types of connectors are dimensions and methods of UTP CABLING coupling. Businesses decide on the types of connectors that will be used, based on their equipment. Properties of UTP Cabling ➔ In the previous topic, you learned a bit Straight Tip (ST) Connector about unshielded twisted-pair (UTP) copper cabling. Because UTP cabling is the ➔ ST connectors were one of the first standard for use in LANs, this topic goes connector types used. The connector locks into detail about its advantages and securely with a 'twist-on/twist-off' limitations, and what can be done to avoid bayonet-style mechanism. problems. ➔ When used as a networking medium, UTP Subscriber Connector (SC) cabling consists of four pairs of color-coded copper wires that have been twisted ➔ SC connectors are sometimes referred to as together and then encased in a flexible 'square connectors' or 'standard plastic sheath. Its small size can be connectors'. They are a widely-adopted LAN advantageous during installation. and WAN connector that uses a push-pull ➔ UTP cable does not use shielding to counter mechanism to ensure positive insertion. the effects of EMI and RFI. Instead, cable This connector type is used with multimode designers have discovered other ways that and single-mode fiber. they can limit the negative effect of crosstalk: Lucent Connector (LC) ➔ Cancellation - Designers now pair wires in a circuit. When two wires in an electrical ➔ Simplex Connector LC simplex connectors circuit are placed close together, their are a smaller version of the SC connector. magnetic fields are the exact opposite of These are sometimes called little or local each other. Therefore, the two magnetic connectors and are quickly growing in fields cancel each other and also cancel out popularity due to their smaller size. any outside EMI and RFI signals. Varying the number of twists per wire pair - To Duplex Multimode (LC) further enhance the cancellation effect of paired circuit wires, designers vary the ➔ Connector A duplex multimode LC number of twists of each wire pair in a connector is similar to an LC simplex cable. UTP cable must follow precise connector, but uses a duplex connector. specifications governing how many twists or Fiber VS Copper braids are permitted per meter (3.28 feet) of cable. Notice in the figure that the orange/orange white pair is twisted less than the blue/blue white pair. Each colored pair is twisted a different number of times. UTP cable relies solely on the cancellation effect produced by the twisted wire pairs to limit signal degradation and effectively provide self-shielding for wire pairs within the network media. UTP Cabling Standards and Connectors OA kong reviewer ➔ UTP cabling conforms to the standards established jointly by the ANSI/TIA. Specifically, ANSI/TIA-568 stipulates the commercial cabling standards for LAN installations and is the standard most commonly used in LAN cabling environments. Some of the elements defined are as follows: Cable types Cable lengths Connectors Cable termination Methods of testing cable ➔ The electrical characteristics of copper cabling are defined by the Institute of Electrical and Electronics Engineers (IEEE). Poorly Terminated UTP Cable IEEE rates UTP cabling according to its performance. Cables are placed into ➔ This bad connector has wires that are categories based on their ability to carry exposed, untwisted, and not entirely higher bandwidth rates. For example, covered by the sheath. Category 5 cable is used commonly in Properly Terminated UTP Cable 100BASE-TX Fast Ethernet installations. Other categories include Enhanced ➔ It is a good connector with wires that are Category 5 cable (5e), Category 6, and untwisted only to the extent necessary to Category 6a. attach the connector. ➔ Cables in higher categories are designed Straight-through and Crossover UTP Cables and constructed to support higher data rates. As new gigabit speed Ethernet ➔ Different situations may require UTP cables technologies are being developed and to be wired according to different wiring adopted, Category 5e is now the minimally conventions. This means that the individual acceptable cable type, with Category 6 wires in the cable have to be connected in being the recommended type for new different orders to different sets of pins in building installations. the RJ-45 connectors. ➔ The following are the main cable types that ➔ UTP cable is usually terminated with an are obtained by using specific wiring RJ-45 connector. The ANSI/TIA-568 conventions: standard describes the wire color codes to ➔ Ethernet Straight-through - The most pin assignments (pinouts) for Ethernet common type of networking cable. It is cables. commonly used to interconnect a host to a switch and a switch to a router. ➔ Ethernet Crossover - A cable used to interconnect similar devices. For example, to connect a switch to a switch, a host to a OA kong reviewer host, or a router to a router. However, DATA LINK LAYER crossover cables are now considered legacy as NICs use medium-dependent Ethernet Frame interface crossover (auto-MDIX) to automatically detect the cable type and ➔ Ethernet is technology commonly used in make the internal connection. local area networks. Devices access the Ethernet LAN using an Ethernet Network Straight-through and Crossover UTP Cables Interface Card (NIC). Each Ethernet NIC has a unique address permanently ➔ Note: Another type of cable is a rollover embedded on the card known as a Media cable, which is Cisco proprietary. It is used Access Control (MAC) address. The MAC to connect a workstation to a router or address for both the source and destination switch console port. are fields in an Ethernet frame. ➔ The Ethernet frame is divided into several ➔ Using a crossover or straight-through cable data sets. The records contain binary code incorrectly between devices may not that include essential information like damage the devices, but connectivity and addresses, control information, payload communication between the devices will not data, as well as checksums. take place. This is a common error and checking that the device connections are correct should be the first troubleshooting action if connectivity is not achieved. ➔ The figure identifies the individual wire pairs for the T568A and T568B standards. S Preamble: It can inform the receiving system that a frame is beginning and enable synchronization. Start Frame Delimiter (SFD): It means that the destination MAC address field start with the next byte. The SFD is 1 byte in length. Destination MAC: This field is 6 bytes long. It includes the MAC address of the T568A - CROSSOVER destination device. T568B - STRAIGHT THROUGH Source MAC: It has the same length with destination MAC address. It contains the MAC address of the source device. It is useful in identifying the source device. Type filed: This filed is 2 bytes long. It defines the type of protocols within the frame like IPv4 and IPv6. Data and Pad: The minimum size of this field is 46 bytes, while the maximum size is 1500 bytes. The network layer cannot pack data that is less or more than the limit in one LESSON 5 packet data of the upper layer. The Data OA kong reviewer and Pad contains the payload data. Frame Check Sequence (FCS): This field is 4 bytes in length. This field usually stores a 4 bytes value that can be applied to examine if the received frame is complete. Besides, it includes a 32-bit Cyclic Redundancy Check (CRC), which permits you to detect corrupted data. Encapsulation HALF-DUPLEX COMMUNICATION ➔ When sending a letter, the letter writer uses an accepted format to ensure that the letter is delivered and understood by the recipient. In the same way, a message that is sent over a computer network follows specific format rules in order for it to be delivered and processed. ➔ The process of placing one message format (the letter) inside another message format (the envelope) is called encapsulation. FULL DUPLEX COMMUNICATION De-encapsulation occurs when the process is reversed by the recipient and the letter is removed from the envelope. Just as a letter is encapsulated in an envelope for delivery, so computer messages are encapsulated. ➔ Each computer message is encapsulated in a specific format, called a frame, before it is sent over the network. A frame acts like an envelope; it provides the address of the intended destination and the address of the source host. The format and contents of a frame are determined by the type of message being sent and the channel over which it is communicated. Messages that are not correctly formatted are not successfully delivered to or processed by Half and Full Duplex Communication the destination host. ➔ In summary, half-duplex communications restrict the exchange of data to one direction at a time. Full-duplex allows the sending and receiving of data to happen simultaneously. It is important that two interconnected interfaces, such as a host NIC and an interface on an Ethernet switch, operate using the same duplex mode. OA kong reviewer Otherwise, there will be a duplex mismatch ➔ Examples of contention-based access creating inefficiency and latency on the link. networks include the following: Wireless LAN (uses CSMA/CA) Access Control Methods Ethernet Legacy bus-topology Ethernet LAN (uses CSMA/CD) ➔ LANs and WLANs are examples of Legacy Ethernet LAN using a hub multiaccess networks. A multiaccess (uses CSMA/CD) network is a network that can have two or more end devices attempting to access the ➔ These networks operate in half-duplex network simultaneously. mode, meaning only one device can send or ➔ Some multiaccess networks require rules to receive at a time. This requires a process to govern how devices share the physical govern when a device can send and what media. There are two basic access control happens when multiple devices send at the methods for shared media: same time. Contention-based access ➔ If two devices transmit at the same time, a Controlled access collision will occur. For legacy Ethernet Contention-based access LANs, both devices will detect the collision on the network. This is the collision ➔ In contention-based multiaccess networks, detection (CD) portion of CSMA/CD. The all nodes are operating in half-duplex, NIC compares data transmitted with data competing for the use of the medium. received, or by recognizing that the signal However, only one device can send at a amplitude is higher than normal on the time. Therefore, there is a process if more media. The data sent by both devices will than one device transmits at the same time. be corrupted and will need to be resent. Examples of contention-based access methods include the following: ➔ Carrier sense multiple access with collision Contention-Based Access - CSMA/CA detection (CSMA/CD) used on legacy bus-topology Ethernet LANs Another form of CSMA used by IEEE 802.11 ➔ Carrier sense multiple access with collision WLANs is carrier sense multiple access/collision avoidance (CSMA/CA) used on Wireless avoidance (CSMA/CA). CMSA/CA uses a method LANs similar to CSMA/CD to detect if the media is clear. CMSA/CA uses additional techniques. In wireless Contention-based access environments, it may not be possible for a device to detect a collision. CMSA/CA does not detect ➔ In a controlled-based multiaccess network, collisions but attempts to avoid them by waiting each node has its own time to use the before transmitting. Each device that transmits medium. These deterministic types of includes the time duration that it needs for the legacy networks are inefficient because a transmission. All other wireless devices receive this device must wait its turn to access the information and know how long the medium will be medium. Examples of multiaccess networks unavailable. that use controlled access include the following: Legacy Token Ring Legacy ARCNET Contention-Based Access - CSMA/CD