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Categorizing Networks. Categories. Physical scope Method of administration Network operating system Network protocols Topology Architecture OSI. Categorizing Networks by Physical Scope. Local-area network Metropolitan-area network Wide-area network. Local-area Networks (LAN). - PowerPoint PPT Presentation

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  • Categorizing Networks

    Gary DeRoest

  • Gary DeRoest

  • CategoriesPhysical scopeMethod of administrationNetwork operating systemNetwork protocolsTopologyArchitectureOSI

    Gary DeRoest

  • Categorizing Networks by Physical ScopeLocal-area networkMetropolitan-area networkWide-area network

    Gary DeRoest

  • Local-area Networks (LAN)Limited to a specific geographic area2 computers connected together in a home office500 computers computers connected together in an office building

    Gary DeRoest

  • Local-area NetworksNetwork architecture and cable type can limit the number of computers a LAN can contain.Large LANs can be divided into workgroups.

    Gary DeRoest

  • Metropolitan-area Network (MAN)Two or more LANs networked together within a city or community.Less frequently used term.

    Gary DeRoest

  • Wide-area Network (WAN)A network spanning a large geographical area.The internet.Private networks.Internet vs. internet.

    Gary DeRoest

  • Wide-area Network (WAN)Intranet a private network within an enterprise using the same protocols as the Internet.Extranet an intranet but made accessible to customers, employees, vendors and partners.

    Gary DeRoest

  • Wide-area Networks (WAN)Use of public transports such as telephone lines slow transmission speedModem: 50 kbpsT1, cable modem, DSL : 1 6 mbpsSlowest Ethernet LAN: 10 mbps

    Gary DeRoest

  • Wide-area Network (WAN)Routed networks.For a message to pass from one segment (LAN) to another, the packets must pass through a gateway.Gateway: a specially configured computer or router which sends packets to another LAN.

    Gary DeRoest

  • Categorizing Networks by Method of AdministrationPeer-to-peerEach computer functions as server and clientEach computer is administered by its userClient/serverAdministration is centralizedSpecial network operating system (NOS) is required

    Gary DeRoest

  • Method of AdministrationA server is a computer that makes its resources available for access by other computers on the network.Data, software, printers A client is a computer that accesses the resources of the server computer.Clients take; Servers give.

    Gary DeRoest

  • Method of AdministrationPeer-to-peerEach computer functions as server and clientEach computer is administered by its userShare Level SecurityClient/serverAdministration is centralizedSpecial network operating system (NOS) is requiredUser Level Security

    Gary DeRoest

  • Method of AdministrationThe operating systems that we think of as client or desktop operating systems Windows 95/98, NT Workstation, and Windows 2000 Pro. can and do function as servers when you create shares on them to enable other computers to use their resources.

    Gary DeRoest

  • Method of AdministrationIf you had a folder named WestProject that you wanted to share over the network, you must assign a name to the share.WP, Wproj, etc.

    Gary DeRoest

  • Method of AdministrationThe share named WestProject appears in the browse list for the server named Gordian.

    Gary DeRoest

  • Method of AdministrationSome network operating systems allow for shared resources to be published to the master directory.Active directory in windows 2000.NDS tree in Novell Netware.This enables users to locate the shared resources without knowing which server hosts the resource.

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  • Method of AdministrationDedicated serversFile serversPrint serversApplication serversLogon serversWeb serversMail serversNews serversRemote access serversTerminal serversTelephony serversCluster serversProxy serversFax serversBOOTP serversDHCP serversName resolution servers

    Gary DeRoest

  • Method of AdministrationA daemon, in UNIX terminology, is a program that runs continuously and handles periodic requests for services.

    Gary DeRoest

  • Method of AdministrationThe term client, again refers to a device requesting services from a server such as:

    Computer, printer, network device, software program

    An e-mail program that runs on your desktop computer that sends requests to download new messages is often called an e-mail client.

    Gary DeRoest

  • Method of AdministrationA workstation generally refers to mean any desktop computer running any client operating system Windows, Linux, Macintosh, etc.

    A workstation can also refer to a powerful computer used to run resource intensive application software.

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  • Method of AdministrationThe term host also can refer to computers on a network. With TCP/IP based networks, host can include any network device that is assigned an IP address.

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  • Method of AdministrationA node is a connection point on a network.

    A computerA printerNetwork device

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  • Characteristics of Peer-to-peer Networks10 computers maximum.Inexpensive.Windows, Linux, Macintosh.Decentralized administration.User accounts must be created and maintained on each node.

    Gary DeRoest

  • Share Level SecurityUsed by windows for workgroups 3.11 and windows 95/98A password assigned for each shared resourceTo access resource, a user must provide the password for that resourceUsers must remember multiple passwords

    Gary DeRoest

  • User Lever SecurityUsed by windows NT and windows 2000A password is assigned to each userAccess to a specific resource only if user has been assigned permissionsUsers need only remember one password

    Gary DeRoest

  • Server-based NetworksCentralized controlNOS installed on 1+ machineNetware, Windows NT, Windows 2000 serverUser accounts maintained on serverIncreased performance & throughputAdditional services provided

    Gary DeRoest

  • Server-based AdministrationSimplifiedShared resources stored on server for easy location and backupRequires a professional network administrator

    Gary DeRoest

  • Server-based SecurityInherently more secure that peer-2-peerRequires user accounts and passwordAccess to resources are granted through user authentication and permissionsNetwork administrator assigns permissions to individual users and groups of users

    Gary DeRoest

  • Categorizing Networks by NOSWindows (NT and 2000)NetwareUNIX

    Networks containing more than one server type are called hybrid networks

    Gary DeRoest

  • Windows Server-based NetworksDomainsPrimary domain controllerSecurity accounts manager (SAM)Downlevel domainsActive directoryCopies stored on each domain controller

    Gary DeRoest

  • Windows Server-based NetworksWhat clients can access Windows NT and 2000 server resources?Windows 2000 pro, Windows 95, Windows 98, Windows for Workgroups 3.11, MS-DOSMacintosh and Linux clients can access resources

    Gary DeRoest

  • Netware Server-based NetworksBindery databaseNDS organize objectsTreesReplicasContextLogin securityFile and print services

    Gary DeRoest

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  • Netware Server-based NetworksWhat clients can access NetWare server resources?Windows 2000 pro, Windows 95, Windows 98, Windows for Workgroups 3.11, MS-DOSClient32 software provides full functionalityMacintosh and Linux clients can access resources with appropriate client software

    Gary DeRoest

  • UNIX Server-based NetworksPowerful NOS developed by Bell Labs in 1969Linux development and other open standard software are recently becoming popularText based and GUI based Administration tools are availableAccess granted by user ID and passwordGroups are collections of users with similar access permissions which simplify administration

    Gary DeRoest

  • UNIX Server-based NetworksWhat clients can access UNIX server resources?Dumb terminals, Linux, Windows 2000 pro, Windows 95, Windows 98, Windows for Workgroups 3.11, MS-DOSMacintosh clients can access resources with appropriate client and server software

    Gary DeRoest

  • UNIX Server-based NetworksHP-UXSUN solarisAIXSCOetc

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  • Hybrid NetworksMost medium to large networks are hybridsAll NOS provide interoperability toolsClient Services for NetWareGateway Services for NetWareMicrosoft NetWare clientFile and print servicesMacintosh servicesSystems Network Architecture (SNA)SAMBA

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  • Categorizing Networks by ProtocolNetBEUIIPX/SPXTCP/IPOthers

    Gary DeRoest

  • NetBEUINetBIOS Extended User InterfaceNetwork Basic Input/Output SystemProvides application programming interfaceDeveloped by IBMUnroutableSimple to setup no complicated configurationLow resource overheadFast

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  • IPX/SPXInternet Package Exchange/Sequenced Packet ExchangeNovell proprietary protocolMinimal configurationFaster performance than TCP/IPNWLink, IPX/SPX, MacIPX

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  • TCP/IPMost popular despite being the most difficult to configure and being slowFlexible addressing scheme extremely routableAlmost all OS can use itLots of utility tools availableThe protocol of the Internet

    Gary DeRoest

  • Others - AppleTalkA set of protocols developed by Apple for networking Macintosh machinesLocalTalkSlow (230.4 kbps) supports only 32 devicesEtherTalkUsed to connect to Ethernet networksTokenTalkUsed to connect to Token Ring networksAppleTalk networks use AppleTalk Address Resolution Protocol (AARP) to map AppleTalk addresses to Ethernet and Token Ring physical Media Access Control (MAC) addresses

    Gary DeRoest

  • Others - OSIOpen Systems InterconnectionIntended to replace TCP/IPDeveloped by the International Organization for Standardization (ISO) isosImproved set of protocols for less confusion and easier standardization of networking products

    Gary DeRoest

  • Categorizing Networks by Topology

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  • Categorizing Networks by TopologyLinear BusRingStarMeshHybrid

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  • Linear Bus Networks

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  • Linear Bus NetworksComputers in a bus network are connected in a line from one to the nextA bus network requires termination at each end to prevent signal bounceUsually use thick or thin coax cable and the Ethernet 10base2 or 10base5 architure

    Gary DeRoest

  • Communications on a BUS NetworkWhen a computer sends a message, it proceeds to each computer on the networkThe NIC examines the headers to determine whether the message is addressed to that computerIf it is not, the message is discarded

    Gary DeRoest

  • Advantages of Bus NetworksSimple and easy to set upRelatively inexpensive (less cable)Suitable for small, temporary networks (gaming)

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  • Disadvantages of Bus NetworksPassive topologyAttenuationMay require repeatersA break in the cable

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  • Ring Networks

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  • Ring NetworksA bus network where the last computer in the chain is connected back to the first computerEach computer is connected to two othersSignal travels in a circleA physical ring network uses coax cableA logical ring network uses STP cable and complies with IEEE 802.5 specifications

    Gary DeRoest

  • Communications on a Ring NetworkCommunications happen in one directionEach computer receives the signal from its upstream neighbor and sends it to its downstream neighbor.Active topology because each computer regenerates the signal before passing it onToken Ring architecture is generally a logical ring. Using a special hub a multistation access unit (MSAU)

    Gary DeRoest

  • Advantages of a Ring NetworkEasy to troubleshootSimple to set upRequires less cable that a star network

    Gary DeRoest

  • Disadvantages of a Ring NetworkIf the ring is broken, all network communications haltAdding computers to the ring can be problematicThe ring must be broken to add the new workstation

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  • Star Networks

    Gary DeRoest

  • Star NetworksThe most popular LAN topologyEach computer is connecter to a central hubHubs can be active passive or intelligentPassive a connection point, no electricityActive boosts the signal before passing alongIntelligent contains processing chip with diagnostic toolsUTP cabling and Ethernet 10BaseT or 100BaseT architecture

    Gary DeRoest

  • Communications on a Star NetworkSignal from the sending computers NIC to the hub, boosted, and sent back on all portsAll computers receive the messageAll computers except the one whos NIC address matches the message header discard the message

    Gary DeRoest

  • Advantages of a Star NetworkVery fault tolerantVery flexibleEasy to add workstationsEasy to reconfigure the topologyEasy to troubleshoot

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  • Disadvantages of a Star NetworkCostLots more cable is requiredHub

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  • Mesh NetworksEvery computer on the network has a direct connection to every other computerAdvantagesThe most fault tolerantAn alternate path exists between two computersDisadvantagesVery, very expensive cable, NICs

    Gary DeRoest

  • Hybrid Networks

    Gary DeRoest

  • Hybrid NetworksA network where elements of the previous network types are usedSeveral hubs can be connected in a bus topologyEach hub however uses a star topology to connect several computers to the network

    Gary DeRoest

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  • Categorizing Networks by ArchitectureIncludes a set of specifications that take into account its Physical and logical topologiesThe type a cable usedDistance limitationsMedia access methodsPacket size and headers Other factors

    Gary DeRoest

  • Categorizing Networks by ArchitectureEthernetToken RingAppleTalkARCnet

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  • Ethernet ArchitectureXerox, Digital, Intel (1960s)IEEE 802.3 specificationsBus or starMedia access CSMA/CD carrier sense multiple access collision detection10 Mbps, 100 Mbps (Fast Ethernet), 1 Gbps

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  • Subcategories of Ethernet Networks10Base510Base210BaseT100BaseT1000BaseT100BaseVG-AnyLAN10BaseFL100BaseFL

    Gary DeRoest

  • 10Base2 Ethernet NetworksUses thinner (approx. -inch in diameter), less expensive, and more flexible cable. Maximum segment length is 185 meters. These thinnet networks are physically structured as a linear bus.Easier to set up and work with than thicknet. Twist-and-push connectors (called BNC connector) are used to connect the cable to a T-connector on the network card.The transceiver is built into the network card.The coaxial cable for a 10Base2 network is 50-ohm RG-58A/U or RG-58C/U

    Gary DeRoest

  • 10BaseT Ethernet NetworksThis is a very popular specification for LANs of all sizes. It can run on Cat 3 cable, which is already installed in many buildings for telephone communications. New 10BaseT networks are usually set up using Cat 5 or Cat 5e cable so that it is easy to upgrade to 100 Mbps later

    Gary DeRoest

  • 100BaseT Ethernet NetworksRefers to Ethernet networks running at 100 Mbps over Cat 5 or Cat 5e cable.Many NICs and hubs are made to support both 10- and 100-Mbps transmission speeds which make it easy to upgrade incrementally.With proper hardware networks can be segmented so one part runs at 10-Mbps while the other part runs at 100-Mbps.

    Gary DeRoest

  • 1000BaseT Ethernet NetworksGigabit Ethernet NetworksThis standard was established by IEEE in 1996, 802.3z.The IEEE 802.3ab standard sets specifications for the operation, testing, and usage requirements for Gigabit Ethernet for distances of up to 100 m, using four pairs of Cat 5 copper cabling.This includes most of the cabling already installed in buildings for 10BaseT and 100BaseT networks.The cost of necessary NICs and hubs are several times higher than that of 100-Mbps components.

    Gary DeRoest

  • 100BaseVG-AnyLAN Ethernet NetworksThis Hewlett Packard developed technology is fast, reliable networking architecture that uses a special type of hub that functions as an intelligent central controller.The hub receives the incoming data packet and directs it only to the port with the matching destination address providing inherent network data security.These networks are placed into the Ethernet category, but they use a different media access method, called demand priority, that is defined in IEEE specification 802.12.

    Gary DeRoest

  • 10BaseFL and 100BaseFL NetworksFL in this specification stands for fiber link and these network use baseband signaling over fiber optic cable.Fiber-optic cabling uses pulse of light instead of electrical signals to represent the 0s and 1s of binary communication used by computers.A big advantage is its resistance to interference and attenuation. A cable segment under FL specifications can be 2000 meters in length, which is 4 times that of 10Base5, over 10 times that of 10Base2, and 20 times the limit for 10BaseT.

    Gary DeRoest

  • Token Ring NetworksThis architecture was developed by IBM in the 1980s. Here, a signal called a token is passed around the circle and a computer cannot broadcast until the token gets around to it. This means that, unlike Ethernet networks, Token Ring networks do not experience data collisions. A data collision occurs when two computers send at the same time.Although logically a ring, Token Ring networks are physically laid out as star topologies. Defined by IEEE 802.5IBM cable types primarily STP. Token Ring cards and other components are generally more expensive but are highly reliable.Older Token Ring components supported only 4-Mbps transmissions, but newer implementations can transfer data at 16 Mbps.

    Gary DeRoest

  • AppleTalk NetworksProtocol suite to network Macintosh computers.AppleShare is a suite of application layer protocols that provide file and print sharing. AppleShare components which are built into the OS include:AppleShare file server Enables users to access the computers resourcesAppleShare print server Provides for sharing of printersAppleShare PC is a service that runs on DOS computers to enable them to access files on an AppleShare file server or print to a shared AppleShare print server.AppleTalk networks can be divided into groups called zones, and serve a purpose similar to dividing a large network into workgroups.

    Gary DeRoest

  • ARCnet NetworksAttached Resource Computer NetworkOld architecture that uses a token-passing access method, but implements the network topology as a bus or star instead of as a ring.The token is passed in numerical order according to the node address, which is an 8-digit binary number set on the ARCnet NIC using DIP switches or jumpers.ARCnet can use coax, UTP, or even fiber-optic cable, but it is most commonly associated with RG-62/U 90-ohm coax cable.ARCnet networks are slow compared to most LAN technologies: 2.5 Mbps for standard ARCnet, although a newer standard called ARCnet Plus improves on this considerably, with a top speed of 20 Mpbs.

    Gary DeRoest

  • Open Systems InterconnectOSI1947140 country membersInternational Organization for Standardization (ISO) Greek isos meaning equalDoD -> August 1990Protocol suite intended to replace TCP/IPhttp://www.iso.ch/iso/en/ISOOnline.frontpage

    Gary DeRoest

  • OSIApplication - user Programs Presentation - data interpretation Session - control of sessions between hosts Transport - transmission control Network - flow control, routing Data Link - maintain and release data Physical - physical media definition

    Gary DeRoest

  • Layer 7 - The Application LayerPrograms which use services of the network reside in this layer. These programs are the ultimate consumer of network services of the lower layers. The transmission of messages used by these programs is the entire goal of the lower protocols.

    Gary DeRoest

  • Layer 7 - The Application LayerExamples of Application Layer programs are:Telnet.File Transfer Protocol FTP.SMTPNetwork Filing System NFS (Sun).SNMP (Simple Network Management Protocol)AppleShare (Apple).Netx (Novell).DOOM! (iD Software) :-).

    Gary DeRoest

  • Layer 6 - The Presentation Layer This layer is involved in formatting data for the purpose of display or printing. Data encryption, protocol, data compression and character set translation such as ASCII EBCDIC are also performed by protocols at this layer.

    Gary DeRoest

  • Layer 6 - The Presentation Layer Examples of Presentation Layer protocols: HTTP Telnet AppleTalk Filing Protocol AFPE-mail gatewayGateway Services for NetwareSystems Network Architecture gateway

    Gary DeRoest

  • Layer 5 - The Session Layer This layer establishes connections or 'conversations' between processes over the network.Examples of Session Layer protocols: TCP Named Pipes NetBIOS Apple protocols ASP, ADSP, ZIP, PAP

    Gary DeRoest

  • Layer 4 - The Transport Layer This layer provides methods of flow control, ordering of received data, and acknowledgement of correctly received data.Ports and Sockets

    Gary DeRoest

  • Layer 4 - The Transport Layer Some examples of Transport Layer protocols are: TCP User Datagram Protocol UDP Netbios/NetBEUI Sequenced Packet Exchange SPX (Novell) VINES Interprocess Communication Protocol VIPCDNS Name Resolution

    Gary DeRoest

  • Layer 3 - The Network Layer This layer provides to the upper layers a means of transmitting "datagrams" over the network to a specified host. This datagram service provides no confirmation of safe delivery of the information. The transmissions are "connectionless" meaning that there is no "continuing conversation" set up between the two hosts. One datagram may have nothing to do with the next one, and indeed, may arrive out of order if they are related.This layer is also responsible for assigning addresses to the hosts and routing packets between interconnected networks.

    Gary DeRoest

  • Layer 3 - The Network Layer Examples of network layer protocols are:IP - the Internet Protocol IPX - a Novell Protocol DDP - Datagram Delivery Protocol - an Apple Protocol DevicesRoutersLayer 3 switches

    Gary DeRoest

  • Layer 2 - The Data-Link Layer This layer is also known as the Media Access Layer (MAC) since its function is to provide access to the physical media to the upper layers. It also is responsible for the detection of physical errors, and notification of such errors, and establishing and terminating logical links.

    Gary DeRoest

  • Layer 2 - The Data-Link Layer Two sub layersMedia Access Control (MAC)physical addressing issuesLogical Link Control (LLC)Logical topology

    Gary DeRoest

  • Layer 2 - The Data-Link Layer Examples of implementations are:IEEE 802.2 (LLC) IEEE 802.3 IEEE 802.5 (token ring) PPP LCP (point to point protocol for serial links)DevicesBridges Layer 2 switches

    Gary DeRoest

  • Layer 1 - The Physical Layer This layer defines the physical media upon which the host is communicating through the network. The physical medium can be coaxial cable, FDDI (fiber), RS232, or even RF. This layer defines the specifics of implementing a particular transmission medium. It defines the type of cable, frequency, terminations, etc. One may see the advantage of dividing network functionality into layers. The Physical layer could be changed to some new technology as it is developed without affecting the operation of upper layers, provided the inter-layer interfaces are implemented properly.

    Gary DeRoest

  • Layer 1 - The Physical Layer Analog versus digital signalingBaseband versus broadband technologyAsynchronous versus synchronous transmissionMultiplexingDoes not add header information to packetNICNetwork architectureMedia typeBus architecture

    Gary DeRoest

  • Layer 1 - The Physical Layer Some examples of Physical Layer implementations:Ethernet 10Base2 10BaseT 100baseT Token Ring Arcnet FDDI wireless (e.g. FM)

    Gary DeRoest

  • Web Sites For More Infohttp://www.netc.org/network_guidehttp://cs.nmhu.edu/osimodelhttp://www.freesoft.org/CIE/Topicshttp://www.gocertify.com/quizzes/osihttp://lovecraft.die.udec.cl/OS/UNIX/unix-hints-and-hacks/19270033.htmhttp://www.pe.net/~rlewis/Resources/james.htmlhttp://www.randywanker.com/OSIhttp://www.itp-journals.com/OSI_7_layer_model_page1.htm

    Gary DeRoest

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