Chapter 13: Network Design and Management

• System Development Life Cycle, SDLC
  • A methodology for a structured approach to the development of a business system; it includes the following phases: planning, analysis, design, implementation, and maintenance.
• System Analyst
  • A professional who is typically responsible for managing a project and following the SDLC phases, particularly the analysis and design.
• Connectivity Maps
  • A series of figures used for modeling computer networks; types include wide area connectivity maps, metropolitan area connectivity maps, and local area overview and detailed connectivity maps.
• Technical Feasibility
  • The characteristic of a project that it can be created and implemented using currently existing technology.
• Financial Feasibility
  • The characteristic of a project that it can be completed as set forth within the budgetary constraints set by the company.
• Operational Feasibility
  • The characteristic of a project that will operate as designed and implemented.
• Time Feasibility
  • The characteristic of a project that it can be installed in a timely fashion that meets organizational needs.
• Payback Analysis
  • A financial analysis technique that charts the initial costs and yearly recurring costs of a proposed system against the projected yearly income, or benefits, derived from the proposed system.
• Time Value of Money
  • A concept that states that one dollar today is worth more than one dollar promised a year from now because today’s dollar can be invested now and therefore accumulate interest.
• Return on Investment, ROI
  • The business term for a “payback,” which occurs when the revenue generated by a new project becomes greater than the expenses associated with that project. When developing a new project, companies often use financial analysis techniques to determine when the project will earn an ROI, in other words, pay for itself.
• Capacity Planning
  • A time-consuming operation in the process of computer network development that involves trying to determine the amount of network bandwidth necessary to support an application or a set of applications.
• Linear Projection
  • A capacity planning technique that involves predicting one or more network capacities based on the current network parameters and multiplying by some constant.
• Computer Simulation
  • A software program used to simulate an often-complex operation, such as simulating a nuclear explosion, or the addition of an additional runway at an airport.
• Benchmarking
  • Involves generating system statistics under a controlled environment and then comparing those statistics against known measurements.
• Analytical Modeling
  • The creation of mathematical equations to calculate various network values during network analysis.
• Baseline
  • One of the best techniques for determining a network’s current capacities.
• Mean Time Between Failures, MTBF
  • The average time a device or system will operate before it fails.
• Mean Time to Repair, MTTR
  • The average time necessary to repair a failure within the computer network.
• Availability
  • The probability that a particular component or system will be available during a fixed time.
• Reliability
  • A calculation of the probability that a component or system will be operational for the duration of a transaction.
• Protocol Analyzer
  • A computer program that monitors a network 24 hours a day, seven days a week, and captures and records all transmitted packets.
• Sniffer
  • Software and hardware devices that can monitor a network to determine if there are an invalid message being transmitted, report network problems such as malfunctioning NICs, and detect traffic congestion problems; like network monitoring software.
• Network Management Protocol
  • Facilitates the exchange of management information between network devices.
• Simple Network Management Protocol, SNMP
  • An industry standard created by the Internet Engineering Task Force; it was originally designed to manage Internet components, but is now also used to manage wide area network and telecommunications systems.
• Agent
  • The software, or management software, that runs in an element; an element’s that has an agent is considered a managed element and can react to SNMP commands and requests.
• SNMP Manager
  • Controls the operations of a managed element and maintains a database of information about all the managed elements in each network.
• Management Information Base, MIB
  • The database that holds the information about each managed device in a network that supports SNMP.
• Remote Network Monitoring, RMON
  • A protocol that allows a network manager to monitor, analyze, and troubleshoot a group of remotely managed elements.

Chapter 12: Network Security

• Mobile Malicious Code
  • A virus or worm that is designed to get transported over the Internet.
• Trojan Horse
  • A destructive piece of code that hides inside a harmless-looking piece of code, such as an e-mail or an application macro.
• Virus
  • A small program that alters the way a computer operates without the knowledge of the computer’s users and often does various types of damage by deleting and corrupting data and program files, or altering operating system components so that the computer operation is impaired or even halted.
• Botnets
  • Malicious programs that take operations on a compromised computer.
• Worm
  • A special type of virus that copies itself from one system to another over a network, without the assistance of a human being.
• Denial-of-Service Attacks
  • A malicious hacking technique that bombards a computer site with so many messages that the site is incapable of performing its normal duties.
• E-Mail Bombing
  • A malicious hacking technique in which a user sends an excessive amount of unwanted e-mail to someone.
• Spoofing
  • A technique, commonly used by hackers, in which the data sender’s identity is disguised, as in the case of an e-mail message that has a return address of someone other than the person sending the e-mail.
• Smurfing
  • The name of an automated program that attacks a network by exploiting Internet Protocol broadcast addressing and other aspects of internet operation.
• Ping Storm
  • A form of attack in which the Internet ping program is used to send a flood of packets to a server to make the server inoperable.
• Phishing
  • A Web-based attack that involves sending the victim an e-mail that is designed to look like a legitimate request coming from a well-known company, and thereby lure the victim into revealing private information.
• Pharming
  • A Web-based attack in which a user seeking to visit a particular company’s Web site is unknowingly redirected to a bogus Web site that look exactly that company’s official Web site.
• Rootkit
  • A program, often malicious, that is stored deep within a user’s operating system and is capable of redirecting user requests and performing errant operations.
• Key logger
  • A program, often malicious, that records each keystroke a user makes on a keyboard at a computer workstation.
• Surveillance
  • A common security measure used to monitor key locations to deter vandalism and theft by using video cameras and intrusion detection.
• Intrusion Detection
  • The ability to electronically monitor data flow and system requests into and out of a system.
• Honeypot
  • A trap that is set by network personnel to detect unauthorized use of a network resource.
• Access Rights
  • Permission assigned to a file or device; determine how a user or group of users may access the file or device.
• Password
  • The most common form of protection from unauthorized use of a computer system; often a string of letters, numbers, and symbols

Chapter 11: Voice Data Delivery and Networks

• Plain Old Telephone Service, POTS
  • The basic telephone system.
• Local Loop
  • The telephone line that leaves your house or business; it consists of either four or eight wires.
• Central Office
  • Contains the equipment that generates a dial tone, interprets the telephone number dialed, checks for special services, and connects the incoming call to the next point.
• Local Access Transport Area, LATA
  • A geographic area, such as a large metropolitan area or part of a larger state. Telephone calls that remain within a LATA are usually considered local telephone calls, while telephone calls that travel from one LATA to another are considered long-distance telephone calls.
• Trunk
  • A telephone connection used by telephone companies that carries multiple telephone signals, is usually digital and high speed, and is not associated with a telephone number.
• Modified Final Judgment
  • A court ruling in 1984 that required the divestiture, or breakup, of AT&T.
• Local Exchange Carriers, LECs
  • The name given to local telephone companies after the division of AT&T in 1984.
• Interexchange Carriers, IECs or IXc’s
  • The name given to long-distance telephone companies after the division of AT&T in 1984.
• Centrex, Central Office Exchange Service
  • A service from local telephone companies through which up-to-date telephone facilities at the telephone company’s central or local office are offered to business users so that they do not need to purchase their own facilities.
• Private Branch Exchange, PBX
  • A large computerized telephone switch that sits in a telephone room on the company property.
• Private Lines
  • A leased telephone line that requires no dialing.
• Telecommunications Act of 1996
  • A major event in the history of the telecommunications industry that, among other things, opened the door for business other than local telephone companies to offer a local telephone service.
• Competitive Local Exchange Carriers, CLECs
  • A new provider of local telephone services.
• Incumbent local Exchange Carriers, ILECs
  • A local telephone company that existed before the Telecommunications Act of 1996.
• 90 Standard
  • A 56,000-bps dial-up modem standard approved by a standards-making organization rather than a single company; it is slightly incompatible with both x2 and K56flex.
• 92 Standard
  • An improvement of the V.90 standard that provides a higher upstream data transfer rate and provides a call waiting service, in which the user’s data connection is put on hold when someone calls the user’s telephone number.
• Digital Subscriber Line, DSL
  • A technology that allows existing twisted pair telephone lines to transmit multimedia materials and high-speed data.
• Symmetric Connection
  • A type of connection in which the transfer speeds in both directions are equivalent.
• Asymmetric Connection
  • A connection in which data flows in one direction at a faster transmission rate than the data flowing in the opposite direction.
• Splinter less DSL
  • A form of digital subscriber line in which there is no POTS signal accompanying the DSL signal, thus there is no need for a splitter.
• xDSL
  • The generic name for the many forms of digital subscriber line, DSL.
• Asymmetric Digital Subscriber Line, ADSL
  • A popular form of digital subscriber line that transmits the downstream data at a faster rate than the upstream data.
• DSL Lite
  • A form of consumer DSL that has lower transmission speeds and thus lower consumer costs.
• Very High Data Rate DSL, VDSL
  • A form of digital subscriber line that is very fast, between 51 and 55 Mbps, over very short distances, less than 300 meters.
• Rate-Adaptive DSL, RADSL
  • A form of digital subscriber line in which the transfer rate can vary depending on noise levels within the telephones line’s local loop.
• Cable Modem
  • A communications device that allows high-speed access to wide area networks, such as the Internet, via a cable television connection.
• Frame Relay
  • A commercially available packet-switched network that was designed for transmitting data over fixed lines as opposed to dial-up lines.
• Permanent Virtual Circuit, PVC
  • A fixed connection between end points in a frame relay network. Unlike a telephone circuit, which is a physical circuit, a PVC is created with software routing tables, thus making it a virtual circuit.
• Layer 2 Protocol
  • A protocol that operates at the second layer, or data link layer, of the OSI seven-layer model.
• Committed Information Rate, CIR
  • The data transfer rate that is agreed on by both the customer and the carrier in a frame relay network.
• Service Level Agreement, SLA
  • A legally binding written document that can include service parameters offered in a service set up between a communications provider and its customer.
• Burst Rate
  • A rate agreed upon between a customer and a frame relay provider; this agreement allows the customer to exceed the committed information rate by a fixed amount for brief moments of time.
• Asynchronous Transfer Mode, ATM
  • A high-speed packet-switched service, like frame relay, that supports various classes of service.
• Virtual Channel Connection, VCC
  • Used in Asynchronous Transfer Mode; a logical connection that is created over a virtual path connection.

Chapter 10: The Internet

Introduction:

Advanced Research Projects Agency, or a.k.a ARPANET, was created in the late 1960. This was the country's first wide area, packet-switched networks. This network was only used by select universities, military bases, and government labs for services such as the file transfer protocol, electronic email, and remote login. Later, the network was divided into two separate networks. The ARPANET and MILNET. MILNET was used only by military personnel. NSFNET replaced ARPANET later on.

• Address resolution protocol (ARP)
  • An internet protocol that takes an IP address in an IP datagram and translates it into the appropriate CSMMA/CD address for delivery on a local area network.
• ARPANET
  • One of the country’s first wide area packet-switched networks; the precursor of the modern Internet; interconnected to research universities, research labs, and select government installations.
• Blog
  • Short for Web Log. An online Web site in the form of a journal
• Cookie
  • Data created by a Web server that is stored on the hard drive of a user’s workstation.
• Datagram
  • The entity or packet of data transmitted in a datagram packet-switched network.
• Domain name
  • The address that identifies a site on the Web.
• Domain name system (DNS)
  • A large, distributed database of Internet addresses and domain names
• Dynamic host configuration protocol (DHCP)
  • An Internet protocol that dynamically assigns Internet addresses to work-station as they request a connection to the internet.
• E-commerce
  • The term that has come to represent the commercial dealings of a business using the Internet.
• Electronic data interchange (EDI)
  • The processing of business orders, purchases, and payments using only electronic data transfers.
• Electronic mail (e-mail)
  • The computerized version of writing a letter and mailing it at the local post office.
• ENUM
  • The Voice over IP standard that converts a telephone number into a fully qualified Internet address.
• E-retailing
  • The selling of goods and services over the Internet.
• Extended simple mail transfer protocol (ESMTP)
  • An Internet protocol for sending and receiving e-mail.
• Extranet
  • When an intranet is extended outside the corporate walls and made available to suppliers, customers, or other external agents.
• File transfer protocol (FTP)
  • One of the first services offered on the Internet, FTP’s primary functions are to allow a user to download a file from a remote site to his or her computer and to upload a file from his or her computer to a remote site
• 323
  • A Voice over IP standard that will probably be replaced by Session Initiation Protocol, SIP.
• Hypertext markup language (HTML)
  • A set of codes inserted into a Web page, that is used by a Web browser to determine how the document is displayed.
• Hypertext transfer protocol (HTTP)
  • An Internet protocol that allows Web browsers and servers to send and receive World Wide Web pages.
• Instant messaging (IM)
  • The sending and receiving of text messages between user and workstations in real time.
• Internet control message protocol (ICMP)
  • Used by routers and nodes, this protocol performs error reporting for the Internet Protocol.
• Internet message access protocol (IMAP)
  • An Internet protocol used to support the storage and retrieval of electronic mail.
• Internet protocol (IP)
  • The software that prepares a packet of data so that it can move from on network to another on the Internet or within a set of networks in a corporation.
• Internet of Things (IoT)
  • Numerous gadgets all connected through a network
• Internet 2
  • A newer, very-high-speed packet-switched wide area network that supplements the currently existing Internet and may eventually replace it.
• Intranet
  • A TCP/IP network inside a company that allows employees to access the company’s information resources through an Internet-like interface.
• IP multicasting
  • The ability of a network server to transmit a data stream to more than one host at a time.
• IPsec
  • A set of protocols, created by the Internet Engineering Task Force, that can provide for secure transmission using the Internet Protocol.
• IPv6
  • A more modern Internet Protocol that takes advantage of the current technology. Currently, most Internet systems are using IPv4
• Listserv
  • A popular software program used to create and manage Internet mailing lists.
• Micro-marketing
  • The marketing that is directed at consumers who use the Internet to purchase goods and services.
• MILNET
  • The network for military use only that the Department of Defense broke apart from the ARPANET in 1983
• Multiprotocol label switching (MPLS)
  • A technique that enables a router to switch data from one path onto another path.
• Multipurpose internet mail extensions (MIME)
  • The protocol used to attach a document, such as a word processor file or spreadsheet, to an e-mail message.
• Network address translation (NAT)
  • An Internet protocol that allows all workstations on a local area network to assume the identity of one Internet address.
• Point-to-point protocol (PPP)
  • A protocol used to connect two devices using a serial interconnection; often used to connect a user’s microcomputer to an Internet service provider via DSL or a dial-up line.
• Post office version protocol version 3 (POP3)
  • An Internet protocol used to store and retrieve electronic mail.
• Private VoIP
  • A voice over IP system that is found within the confines of a company’s system of networks and does not extend to the Internet.
• Real-time protocol (RTP)
  • An application layer protocol that servers and the Internet use to deliver streaming audio and video data to a user’s browser.
• Real-time streaming protocol (RTSP)
  • An application layer protocol that servers and the Internet use to deliver streaming audio and video data to a user’s browser.
• Remote login
  • The Internet application that allows you to log in to a remote computer.
• Session initiation protocol (SIP)
  • A standard created by the Internet Engineering Task Force for supporting Voice over IP, the transfer of voice over the Internet.

Chapter 9: Introduction to Metropolitan Area Networks and Wide Area Networks

Metropolitan Area Network Basics:

The differences between a MAN and a LAN are:

1. MANs cover wider geographical areas. For example, MANs have the capability to cover an entire city like Chicago. LANs can only cover an entire building.
2. MANs recover more quickly to switch/router failures.
3. Most MAN's topologies are based on a ring both physically and logically.
4. MAN have the ability to allocate bandwidth on demand.

SONET vs Ethernet:

All MAN networks are based on two different kinds of technology: SONET (Synchronous Time Division Multiplexing Technique) and Ethernet. SONET's have a low failover rate because of their topology. SONETs are consisted of a ring topology, but these rings are composed of multiple rings within the ring that help with backup in case of a segment failure. However, SONETs have their disadvantages. This technology can be expensive because of its complexity and they have issues with scaling from T-1 transmissions to 1-Mbps, 10-Mbps, and 100-Mbps.

Ethernet MANs are less expensive and are better understood and can have the ability to scale from 10-Mbps to as much as 10 Gbps. The problem with ethernets, however, is their failover rate. Routing/Switching failures are higher than the SONET technology.

Wide Area Network Basics:

A wide area network is "a collection of computers and computer-related equipment interconnected to perform a given function or functions, typically using local and long-distance telecommunications systems." WANs connect each workstation through the use of a "mesh" design and use a routring device to transport data across the network. In this case, neighbors will only be connected to other neighbors. All WANs are collections of two different types of equipment: nodes and workstations. Nodes are devices that allow other workstations to access the physical network and are also transfer points for passing data through the network. To support the wide area network, a network cloud is provided within the WAN. The network cloud is the subnetwork of the WAN, which will contain a collection of nodes and interconnecting telecommunication links. The network cloud is the underlying physical interconnection of nodes and communications lines that transfer data from one location to another. The cloud is responsible for guiding the data to the proper destination node. The network cloud is simply a vehicle for the data that is to be transported from one workstation to another.

Types of network clouds:

There are three different types of network clouds: circuit-switched network, packet-switched network, and broadcast.

Circuit-switched network is a network cloud in which a dedicated circuit is established between the sender and the receiver, and all other data will pass over this dedicated line. When a connection is requested for this kind of network, time is needed to establish the circuit and to tear down the circuit. The problems with circuit-switched networks is they only contain one connection, and the circuit may not be utilizing the connection fully due to the sporadic behavior of circuit-switched networks.

Packet-switched network will transmit all data messages using fixed-sized packages. The connection is not established. The data will be broken down into various packets from the sender and then reassembled at the requested destination. There are two types of packet-switched networks: datagram and the virtual circuit. Datagrams allows each data packet to follow its own unique path from each node, which will help with congestion or failures. The problem of datagrams is that each packet will need to analyzed. This could lead to inefficiencies and wasted time. Virtual circuits will send out a notification to routers that will participate in the transportation of various data packets through the network. Once each router has completed its task, that dedicate line will dissolve. This is why it is called a virtual circuit because a dedicated line is established, but that line is then removed when the message has arrived to its specified destination.

Connection oriented versus connectionless network applications:

Connection-oriented network applications provide "guarantees" that the data that is transferred will not be lost over the network. The data will also be sent to the intended receiver. This type of network will provide a "reliable service," which will need a logical connection to be established between two endpoints.

Connectionless network application does not require an established logical connection between two endpoints. This leads to the loss of data and information over the network.

Routing:

Weighted network graph is a way to assign conditions for various connections between various devices. This will help traverse the network. Each communication link will have a weight which will contain a specific meaning. One line connection will have a weight will different meanings. Some will have dollar costs for using the connection and others will have time-delay costs.

Dijkstra's least-cost algorithm is an algorithm that will calculate the least-cost path through a network. The algorithm is executed and then stored within the node that has executed the code. Some nodes will also share the algorithm. However, this algorithm is time consuming. Therefore, the execution of the code is only periodic or when something changes within the network.

Flooding is when a node will take an incoming packet from another node and will transmit the packet to every outgoing link. There are two common rules associated with this technique:

1. The node receiving the packet will not send a copy back to the sender. 
2. A "hop limit" will be required to limit the number of copies that are created. 

Centralized versus distributed routing:

Centralized routing is routing information that is stored in a central location. When a router needs information for various incoming packets, the router will "query" this central location for the information that is associated with the packet.

Distributed routing uses an algorithm to generate routing information and dictates that this information to be stored at various distributed locations within the network.