Transcript Document
Internet Architecture Day 8 Agenda Return 5 and review assignment # 2 A’s, 3 B’s, 1 D, 2 non-submits Quiz # 1 on Oct 4 Chap 1, 2 & 3 20 M/C, 1 Essay (choice of 3), 1 Extra credit 45 Min Open Book Open Notes Lecture/Discuss Internet Architecture 2 Awad –Electronic Commerce 1/e © 2002 Prentice Hall Internet Architecture Overview What is a Network? IP Addresses Networks Information Transfer Cable Types Key Components of a Network Factors in Designing a Network Network Management System 3 Awad –Electronic Commerce 1/e © 2002 Prentice Hall Internet Architecture: What is a Network? What is a Network? A connection between at least two computers for the purpose of sharing resources Types: Local Area Networks (LANs) Wide Area Networks (WANs) Metropolitan Area Networks (MANs) 4 Awad –Electronic Commerce 1/e © 2002 Prentice Hall Internet Architecture: What is a Network? Peer-to-peer Network Computers linked together as equals No centralized control Share resources on the same network in any way & any time Promotes institutionalized chaos < 10 computers 5 Awad –Electronic Commerce 1/e © 2002 Prentice Hall Internet Architecture: What is a Network? Peer-to-peer Network (Cont’d) Benefits Easy to install/configure Inexpensive User is able to control their own resources Independent from a dedicated server No need for a network administrator Drawbacks 6 Security problems Performance suffers when a computer is accessed Difficult to have backup Decentralized logon passwords No centralized data management Awad –Electronic Commerce 1/e © 2002 Prentice Hall Internet Architecture: What is a Network? Client/Server Network – designed to address a client’s request Client – any computer connected to the server within a network Allow authorized user to access any programs/application resided on the server Server 7 Awad –Electronic Commerce 1/e © 2002 Prentice Hall Internet Architecture: What is a Network? Client/Server Network (Cont’d) Benefits Centralized security control Simpler network administration than peerto-peer network Centralized password More scalable Ideal for computers are apart Drawbacks 8 Network failure = clients are helpless Specialized staff are needed Higher costs Awad –Electronic Commerce 1/e © 2002 Prentice Hall Internet Architecture: IP Addresses IP Addresses A host number to identify itself to other hosts Consists of strings of 32 bits E.g. 10111111010101010100000000001100 = 191.170.64.12 Host Name Human-friendly internet addresses E.g. ema3z.mcintire.virginia.edu 9 Awad –Electronic Commerce 1/e © 2002 Prentice Hall Internet Architecture: Networks Networks Network vs. Local Networks are classified by three sizes: Class Beginning Bit Bits in remainder of network part # of bits in local part Max. # of networks Max. # of hosts in network A 0 (1-127) 7 24 136 16 million B 10(128-191) 14 16 16,000 65,000 C 110(192-223) 21 8 2 million 254 10 Awad –Electronic Commerce 1/e © 2002 Prentice Hall Numbers of Hosts # of networks # Hosts / network total Class A 126 16,777,214 2,113,928,964 Class B 16,382 65,534 1,073,577,988 Class C 2,097,150 254 532,676,100 3,720,183,052 11 Awad –Electronic Commerce 1/e © 2002 Prentice Hall Internet Architecture: Networks Networks (Cont’d) Zones Three-letter kind (com, gov, edu) Two-letter kind (ca, uk, jp) New general-purpose zones (firm, store) More Information at The Internet Assigned Numbers Authority http://www.iana.org/domain-names.htm 12 Awad –Electronic Commerce 1/e © 2002 Prentice Hall Network Names (TLDs) AERO air-transport industry ARPA Address and Routing Parameter Area BIZ business COM commercial COOP cooperatives EDU U.S. educational GOV U.S. government INFO information INT international organizations MIL U.S. military MUSEUM museums NAME individuals, by name NET network ORG organization PRO professions 13 Awad –Electronic Commerce 1/e © 2002 Prentice Hall Day 9 Agenda Quick Review Quiz # 1 Today 20 M/C, 1 Essay (choice of 3), 1 Extra credit 45 Min Open Book Open Notes Lecture/Discuss Internet Architecture Assignment # 3 Do even numbered Review Question on Page 125 & 126 (2, 4, 6, …20) Turn in a well formatted typed response sheet Due Tuesday, October 8 at start of class 14 Awad –Electronic Commerce 1/e © 2002 Prentice Hall Day 10 Agenda Get Assignment #3 Return and Review Quiz 2 A’s, 2 B’s, 6 C’s, 1 F Finish Discussion on Chap 4 Next Class we will discus Case Study and Initiative papers. 15 Awad –Electronic Commerce 1/e © 2002 Prentice Hall Internet Architecture: Information Transfer Information Transfer Packet Grouping of data for transmission on a network Large messages are split into a series of packets for transmission Protocol A rule governing how communication should be conducted Internet Protocol Set of rules used to pass packets 16 Awad –Electronic Commerce 1/e © 2002 Prentice Hall Internet Architecture: Information Transfer Information Transfer (Cont’d) Open Systems Interconnection (OSI) A layered approach to networking Each layer handles a different portion of the communication process 17 Awad –Electronic Commerce 1/e © 2002 Prentice Hall Internet Architecture: Information Transfer OSI Reference Model Layer Info Transacted TCP/IP Protocols Application Application messages HTTP, FTP, SNMP Presentation Compressed data Session Session messages Transport Multiple packets TCP Network Packets IP Data Link Frames Ethernet, PPP Physical Bits Wiring, cables 18 Awad –Electronic Commerce 1/e © 2002 Prentice Hall Internet Architecture: Information Transfer OSI Reference Model (Cont’d) Application Layer Defines requests & response formats Standard: HTTP Governs requests & response between browser & web server application program Other standards: SMTP, POP HTML-compatible File Transfer Protocol (FTP), Simple Network Management Protocol (SNMP), Domain Name Service (DNS) 19 Awad –Electronic Commerce 1/e © 2002 Prentice Hall Internet Architecture: Information Transfer OSI Reference Model (Cont’d) Presentation Layer Converts data into a format the receiving application can understand Session Layer Exchanges data for the duration of session Keeps track of the status of exchange Ensures only designated parties are allowed to participate in the session Enforces security protocols for controlling access 20 Awad –Electronic Commerce 1/e © 2002 Prentice Hall Internet Architecture: Information Transfer OSI Reference Model (Cont’d) Transport Layer Manages the transmission of data across a network Transmission Control Protocol (TCP) Specifies how two host computers will work together Flow control Sequence assurance Reliability & integrity 21 Awad –Electronic Commerce 1/e © 2002 Prentice Hall Internet Architecture: Information Transfer OSI Reference Model (Cont’d) Internet Layer Routes messages across multiple nodes for delivery Handles network congestion to minimize performance problems Internet Protocol (IP) Standard for routing packets 22 Awad –Electronic Commerce 1/e © 2002 Prentice Hall Internet Architecture: Information Transfer OSI Reference Model (Cont’d) Data Link Layer Packages data into frames for delivery Point-to-point (PPP) Framing – mark boundary between packets Error detection Ethernet Physical Layer Converts bits into signals for outgoing messages & signals into bits for incoming messages 23 Awad –Electronic Commerce 1/e © 2002 Prentice Hall Internet Architecture: Cable Types Cable Types Twisted-Pair Cable Unshielded Twisted Pair (UTP) Shielded Twisted Pair (STP) Optical Fiber Coaxial Cable Wireless Technology 24 Awad –Electronic Commerce 1/e © 2002 Prentice Hall UTP Cable 25 Awad –Electronic Commerce 1/e © 2002 Prentice Hall Internet Architecture: Cable Types Twisted-Pair Cable Consists of two pairs of insulated copper wires twisted around each other Advantages Protect against cross talk & interference Easy to add computers to network Well understood technology Less expensive Disadvantages Susceptibility to noise Least secure Distance limitations Requires more expensive26hubs Awad –Electronic Commerce 1/e © 2002 Prentice Hall Internet Architecture: Cable Types Unshielded Twisted Pair (UTP) Pair of wires do not have the shielding against electrical interference Advantages Less expensive Easy to install Disadvantages Vulnerable to electromagnetic interference & crosswalk Subject to attenuation 27 Awad –Electronic Commerce 1/e © 2002 Prentice Hall Internet Architecture: Cable Types Shielded Twisted Pair (STP) An electrically grounded woven copper mesh wrapped around each twisted pair Advantage Reduces electromagnetic interference (EMI) Disadvantage Makes the wiring thick and is difficult to maintain 28 Awad –Electronic Commerce 1/e © 2002 Prentice Hall Optical Fiber 29 Awad –Electronic Commerce 1/e © 2002 Prentice Hall Internet Architecture: Cable Types Optical Fiber Uses light rather than voltage to indicate one and zeros Advantages High speed transmission High security Smallest in size Supports voice & video data Disadvantages Expensive Difficult to install Require two cables to transmit & receive data Awad –Electronic Commerce 1/e 30 © 2002 Prentice Hall Require special connections Coaxial Cable 31 Awad –Electronic Commerce 1/e © 2002 Prentice Hall Internet Architecture: Cable Types Coaxial Cable Copper center shielded by a plastic insulating material Advantages Transmits up to 10Mbps over 500m Easy to install Low maintenance Good resistance to noise over long distances Disadvantages Inflexible Low security Limited distance 32 Awad –Electronic Commerce 1/e © 2002 Prentice Hall Internet Architecture: Cable Types Wireless Technology Microwave Connect Radio LANs in separate buildings waves No distance limitations Susceptible to atmospheric and electronic interference Subject to government regulations Infrared transmissions Interference from bright light 33 Awad –Electronic Commerce 1/e © 2002 Prentice Hall Internet Architecture: Key Components of a Network Key Components of A Network Network Interface Card (NIC) Hubs & Switches Routers Gateways 34 Awad –Electronic Commerce 1/e © 2002 Prentice Hall Internet Architecture: Key Components of a Network Network Interface Card Installed in a slot with a cable plugged into the back Plugged into a wall jack connection or into the hub/switch directly Modem Converts digital signals into analog form for transmission and incoming analog signals into digital signal across the telephone line 35 Awad –Electronic Commerce 1/e © 2002 Prentice Hall Internet Architecture: Key Components of a Network Hubs & Switches Hub Operates at Physical Layer Acts as a connecting point Passive, active, and intelligent hubs Switch Offers direct connection to a particular PC Available for almost every OSI level 36 Awad –Electronic Commerce 1/e © 2002 Prentice Hall Internet Architecture: Key Components of a Network Routers Operate at Internet Layer Evaluate network traffic and stop local traffic from causing congestion Filter out packets that need not be received Expensive & difficult to operate 37 Awad –Electronic Commerce 1/e © 2002 Prentice Hall Internet Architecture: Key Components of a Network Gateways Special-purpose computer allowing communications between dissimilar systems on the network Operate at Application Layer primarily Difficult to install & configure Expensive 38 Awad –Electronic Commerce 1/e © 2002 Prentice Hall Internet Architecture: Factors in Designing a Network Factors in Designing a Network Location Capacity Distance limitations Cost Potential growth Security 39 Awad –Electronic Commerce 1/e © 2002 Prentice Hall Internet Architecture: Factors in Designing a Network Factors in Selecting Network Architecture Hardware requirements Software requirements Disaster recovery & fault-tolerance requirements Corporate culture and organizational factors 40 Awad –Electronic Commerce 1/e © 2002 Prentice Hall Internet Architecture: Network Management System Network Management System Manager Managed Nodes Objects Management Information Base (MIB) Requests & responses 41 Awad –Electronic Commerce 1/e © 2002 Prentice Hall Mangement Implications Technical Talents Required Programming Procedural & Scripting Object Oriented Markup Languages Networks Databases System analysis Design Administration Security Needs assessment System design and Specification Project Management 42 Design Transaction programming Administration Awad –Electronic Commerce 1/e © 2002 Prentice Hall Management Implications High demand for Technical talent Project Management Business Knowledge Communication Skills Retaining Talent Constructive & Timely Feedback Recognition & Appreciation Championing Staff Causes Support Employee Career goals Match Industry Standards for Salary 43 Awad –Electronic Commerce 1/e © 2002 Prentice Hall