categorizing networks

8/28/2002 Gary DeRoest 1

Categorizing NetworksCategorizing NetworksCategorizing NetworksCategorizing Networks


CategoriesCategoriesCategoriesCategories

Physical scopePhysical scope Method of administrationMethod of administration Network operating systemNetwork operating system Network protocolsNetwork protocols TopologyTopology ArchitectureArchitecture

– OSIOSI


Categorizing Networks by Categorizing Networks by Physical ScopePhysical Scope

Categorizing Networks by Categorizing Networks by Physical ScopePhysical Scope

Local-area networkLocal-area network Metropolitan-area networkMetropolitan-area network Wide-area networkWide-area network


Local-area Networks (LAN)Local-area Networks (LAN)Local-area Networks (LAN)Local-area Networks (LAN)

Limited to a specific Limited to a specific geographic areageographic area

2 computers 2 computers connected together in connected together in a home officea home office

500 computers 500 computers computers connected computers connected together in an office together in an office buildingbuilding


Local-area NetworksLocal-area NetworksLocal-area NetworksLocal-area Networks

Network architecture and cable type can limit Network architecture and cable type can limit the number of computers a LAN can contain.the number of computers a LAN can contain.

Large LANs can be divided into workgroups.Large LANs can be divided into workgroups.


Metropolitan-area Network Metropolitan-area Network (MAN)(MAN)

Metropolitan-area Network Metropolitan-area Network (MAN)(MAN)

Two or more LANs networked together within Two or more LANs networked together within a city or community.a city or community.

Less frequently used term.Less frequently used term.


Wide-area Network (WAN)Wide-area Network (WAN)Wide-area Network (WAN)Wide-area Network (WAN)

A network spanning a large geographical area.A network spanning a large geographical area. The internet.The internet. Private networks.Private networks. Internet vs. internet.Internet vs. internet.



Intranet – a private network within an Intranet – a private network within an enterprise using the same protocols as the enterprise using the same protocols as the Internet.Internet.

Extranet – an intranet but made accessible to Extranet – an intranet but made accessible to customers, employees, vendors and partners.customers, employees, vendors and partners.


Wide-area Networks (WAN)Wide-area Networks (WAN)Wide-area Networks (WAN)Wide-area Networks (WAN)

Use of public transports such as telephone lines Use of public transports such as telephone lines slow transmission speedslow transmission speed

Modem: 50 kbpsModem: 50 kbps T1, cable modem, DSL : 1 – 6 mbpsT1, cable modem, DSL : 1 – 6 mbps Slowest Ethernet LAN: 10 mbpsSlowest Ethernet LAN: 10 mbps



Routed networks.Routed networks. For a message to pass from one segment (LAN) For a message to pass from one segment (LAN)

to another, the packets must pass through a to another, the packets must pass through a gateway.gateway.

Gateway: a specially configured computer or Gateway: a specially configured computer or router which sends packets to another LAN.router which sends packets to another LAN.


Categorizing Networks by Categorizing Networks by Method of AdministrationMethod of AdministrationCategorizing Networks by Categorizing Networks by Method of AdministrationMethod of Administration

Peer-to-peerPeer-to-peer– Each computer functions as server and clientEach computer functions as server and client

– Each computer is administered by its userEach computer is administered by its user Client/serverClient/server

– Administration is centralizedAdministration is centralized

– Special network operating system (NOS) is Special network operating system (NOS) is requiredrequired


Method of AdministrationMethod of AdministrationMethod of AdministrationMethod of Administration

A server is a computer that makes its resources A server is a computer that makes its resources available for access by other computers on the available for access by other computers on the network.network.– Data, software, printers …Data, software, printers …

A client is a computer that accesses the A client is a computer that accesses the resources of the server computer.resources of the server computer.

Clients take; Servers give.Clients take; Servers give.



•Peer-to-peer–Each computer functions as server and client–Each computer is administered by its user–Share Level Security

•Client/server–Administration is centralized–Special network operating system (NOS) is required–User Level Security



The 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.



If you had a folder If you had a folder named named WestProjectWestProject that that you wanted to share you wanted to share over the network, you over the network, you must assign a name to must assign a name to the share.the share.

WP, Wproj, etc.WP, Wproj, etc.


Method of AdministrationMethod of AdministrationMethod of AdministrationMethod of Administration The share named WestProject appears in the browse list The share named WestProject appears in the browse list

for the server named Gordian.for the server named Gordian.



Some network operating systems allow for shared Some network operating systems allow for shared resources to be “published” to the master directory.resources to be “published” to the master directory.

– Active directory in windows 2000.Active directory in windows 2000.

– NDS tree in Novell Netware.NDS tree in Novell Netware.

This enables users to locate the shared resources This enables users to locate the shared resources without knowing which server hosts the resource.without knowing which server hosts the resource.


Method of AdministrationMethod of AdministrationMethod of AdministrationMethod of Administration Dedicated serversDedicated servers

– File serversFile servers– Print serversPrint servers– Application Application

serversservers– Logon serversLogon servers– Web serversWeb servers– Mail serversMail servers– News serversNews servers– Remote access Remote access

serversservers– Terminal serversTerminal servers

– Telephony serversTelephony servers

– Cluster serversCluster servers

– Proxy serversProxy servers

– Fax serversFax servers

– BOOTP serversBOOTP servers

– DHCP serversDHCP servers

– Name resolution Name resolution serversservers



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



•The 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.



•A 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.



•The 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.



•A node is a connection point on a network.

•A computer

•A printer

•Network device


Characteristics of Peer-to-peer Characteristics of Peer-to-peer NetworksNetworks

Characteristics of Peer-to-peer Characteristics of Peer-to-peer NetworksNetworks

10 computers maximum.10 computers maximum. Inexpensive.Inexpensive. Windows, Linux, Macintosh.Windows, Linux, Macintosh. Decentralized administration.Decentralized administration. User accounts must be created and maintained User accounts must be created and maintained

on each node.on each node.


Share Level SecurityShare Level SecurityShare Level SecurityShare Level Security

Used by windows for workgroups 3.11 and Used by windows for workgroups 3.11 and windows 95/98windows 95/98

A password assigned for each shared resourceA password assigned for each shared resource To access resource, a user must provide the To access resource, a user must provide the

password for that resourcepassword for that resource Users must remember multiple passwordsUsers must remember multiple passwords


User Lever SecurityUser Lever SecurityUser Lever SecurityUser Lever Security

Used by windows NT and windows 2000Used by windows NT and windows 2000 A password is assigned to each userA password is assigned to each user Access to a specific resource only if user has Access to a specific resource only if user has

been assigned permissionsbeen assigned permissions Users need only remember one passwordUsers need only remember one password


Server-based NetworksServer-based NetworksServer-based NetworksServer-based Networks

Centralized controlCentralized control NOS installed on 1+ machineNOS installed on 1+ machine Netware, Windows NT, Windows 2000 serverNetware, Windows NT, Windows 2000 server User accounts maintained on serverUser accounts maintained on server Increased performance & throughputIncreased performance & throughput Additional services providedAdditional services provided


Server-based AdministrationServer-based AdministrationServer-based AdministrationServer-based Administration

SimplifiedSimplified Shared resources stored on server for easy Shared resources stored on server for easy

location and backuplocation and backup Requires a professional network administratorRequires a professional network administrator


Server-based SecurityServer-based SecurityServer-based SecurityServer-based Security

Inherently more secure Inherently more secure that peer-2-peerthat peer-2-peer

Requires user accounts Requires user accounts and passwordand password

Access to resources are Access to resources are granted through user granted through user authentication and authentication and permissionspermissions

Network administrator Network administrator assigns permissions to assigns permissions to individual users and individual users and groups of usersgroups of users


Categorizing Networks by NOSCategorizing Networks by NOSCategorizing Networks by NOSCategorizing Networks by NOS

Windows (NT and 2000)Windows (NT and 2000) NetwareNetware UNIXUNIX

Networks containing more than one server type Networks containing more than one server type are called are called hybrid networkshybrid networks


Windows Server-based NetworksWindows Server-based NetworksWindows Server-based NetworksWindows Server-based Networks

DomainsDomains Primary domain controllerPrimary domain controller Security accounts manager (SAM)Security accounts manager (SAM) Downlevel domainsDownlevel domains Active directoryActive directory

– Copies stored on each domain controllerCopies stored on each domain controller


Windows Server-based NetworksWindows Server-based NetworksWindows Server-based NetworksWindows Server-based Networks

What clients can access Windows NT and 2000 What clients can access Windows NT and 2000 server resources?server resources?– Windows 2000 pro, Windows 95, Windows 98, Windows 2000 pro, Windows 95, Windows 98,

Windows for Workgroups 3.11, MS-DOSWindows for Workgroups 3.11, MS-DOS Macintosh and Linux clients can access Macintosh and Linux clients can access

resourcesresources


Netware Server-based NetworksNetware Server-based NetworksNetware Server-based NetworksNetware Server-based Networks

Bindery databaseBindery database NDS – organize objectsNDS – organize objects TreesTrees ReplicasReplicas ContextContext Login securityLogin security File and print servicesFile and print services


Netware Server-based NetworksNetware Server-based NetworksNetware Server-based NetworksNetware Server-based Networks

What clients can access NetWare server What clients can access NetWare server resources?resources?– Windows 2000 pro, Windows 95, Windows 98, Windows 2000 pro, Windows 95, Windows 98,

Windows for Workgroups 3.11, MS-DOSWindows for Workgroups 3.11, MS-DOS Client32 software provides full functionalityClient32 software provides full functionality Macintosh and Linux clients can access Macintosh and Linux clients can access

resources with appropriate client softwareresources with appropriate client software


UNIX Server-based NetworksUNIX Server-based NetworksUNIX Server-based NetworksUNIX Server-based Networks

Powerful NOS developed by Bell Labs in 1969Powerful NOS developed by Bell Labs in 1969 Linux development and other open standard Linux development and other open standard

software are recently becoming popularsoftware are recently becoming popular Text based and GUI based Administration Text based and GUI based Administration

tools are availabletools are available Access granted by user ID and passwordAccess granted by user ID and password GroupsGroups are collections of users with similar are collections of users with similar

access permissions which simplify access permissions which simplify administrationadministration



What clients can access UNIX server What clients can access UNIX server resources?resources?– Dumb terminals, Linux, Windows 2000 pro, Dumb terminals, Linux, Windows 2000 pro,

Windows 95, Windows 98, Windows for Windows 95, Windows 98, Windows for Workgroups 3.11, MS-DOSWorkgroups 3.11, MS-DOS

Macintosh clients can access resources with Macintosh clients can access resources with appropriate client and server softwareappropriate client and server software



HP-UXHP-UX SUN solarisSUN solaris AIXAIX SCOSCO etcetc


Hybrid NetworksHybrid NetworksHybrid NetworksHybrid Networks

Most medium to large networks are hybridsMost medium to large networks are hybrids All NOS provide interoperability toolsAll NOS provide interoperability tools

– Client Services for NetWareClient Services for NetWare– Gateway Services for NetWareGateway Services for NetWare– Microsoft NetWare clientMicrosoft NetWare client– File and print servicesFile and print services– Macintosh servicesMacintosh services– Systems Network Architecture (SNA)Systems Network Architecture (SNA)– SAMBASAMBA


Categorizing Networks by Categorizing Networks by ProtocolProtocol

Categorizing Networks by Categorizing Networks by ProtocolProtocol

NetBEUINetBEUI IPX/SPXIPX/SPX TCP/IPTCP/IP OthersOthers


NetBEUINetBEUINetBEUINetBEUI

NetBIOS Extended User InterfaceNetBIOS Extended User Interface Network Basic Input/Output SystemNetwork Basic Input/Output System

– Provides application programming interfaceProvides application programming interface Developed by IBMDeveloped by IBM UnroutableUnroutable Simple to setup – no complicated configurationSimple to setup – no complicated configuration Low resource overheadLow resource overhead Fast Fast


IPX/SPXIPX/SPXIPX/SPXIPX/SPX

Internet Package Exchange/Sequenced Packet Internet Package Exchange/Sequenced Packet ExchangeExchange

Novell proprietary protocolNovell proprietary protocol Minimal configurationMinimal configuration Faster performance than TCP/IPFaster performance than TCP/IP NWLink, IPX/SPX, MacIPXNWLink, IPX/SPX, MacIPX


TCP/IPTCP/IPTCP/IPTCP/IP

Most popular despite being the most difficult to Most popular despite being the most difficult to configure and being slowconfigure and being slow– Flexible addressing scheme – extremely routableFlexible addressing scheme – extremely routable

– Almost all OS can use itAlmost all OS can use it

– Lots of utility tools availableLots of utility tools available

– The protocol of the InternetThe protocol of the Internet


Others - AppleTalkOthers - AppleTalkOthers - AppleTalkOthers - AppleTalk

A set of protocols developed by Apple for A set of protocols developed by Apple for networking Macintosh machinesnetworking Macintosh machines– LocalTalkLocalTalk

Slow (230.4 kbps) supports only 32 devicesSlow (230.4 kbps) supports only 32 devices

– EtherTalkEtherTalk Used to connect to Ethernet networksUsed to connect to Ethernet networks

– TokenTalkTokenTalk Used to connect to Token Ring networksUsed to connect to Token Ring networks

AppleTalk networks use AppleTalk Address Resolution AppleTalk networks use AppleTalk Address Resolution Protocol (AARP) to map AppleTalk addresses to Ethernet Protocol (AARP) to map AppleTalk addresses to Ethernet and Token Ring physical Media Access Control (MAC) and Token Ring physical Media Access Control (MAC) addressesaddresses


Others - OSIOthers - OSIOthers - OSIOthers - OSI

Open Systems InterconnectionOpen Systems Interconnection Intended to replace TCP/IPIntended to replace TCP/IP Developed by the International Organization Developed by the International Organization

for Standardization (ISO) for Standardization (ISO) isosisos

Improved set of protocols for less confusion Improved set of protocols for less confusion and easier standardization of networking and easier standardization of networking productsproducts


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ategorizing N

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Topology

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Topology


Categorizing Networks by Categorizing Networks by TopologyTopology

Categorizing Networks by Categorizing Networks by TopologyTopology

Linear BusLinear Bus RingRing StarStar MeshMesh HybridHybrid


Linear Bus NetworksLinear Bus NetworksLinear Bus NetworksLinear Bus Networks


Linear Bus NetworksLinear Bus NetworksLinear Bus NetworksLinear Bus Networks

Computers in a bus network are connected in a Computers in a bus network are connected in a line from one to the nextline from one to the next

A bus network requires termination at each A bus network requires termination at each end to prevent signal bounceend to prevent signal bounce

Usually use thick or thin coax cable and the Usually use thick or thin coax cable and the Ethernet 10base2 or 10base5 architureEthernet 10base2 or 10base5 architure


Communications on a BUS Communications on a BUS NetworkNetwork

Communications on a BUS Communications on a BUS NetworkNetwork

When a computer sends a message, it proceeds When a computer sends a message, it proceeds to each computer on the networkto each computer on the network

The NIC examines the headers to determine The NIC examines the headers to determine whether the message is addressed to that whether the message is addressed to that computercomputer

If it is not, the message is discardedIf it is not, the message is discarded


Advantages of Bus NetworksAdvantages of Bus NetworksAdvantages of Bus NetworksAdvantages of Bus Networks

Simple and easy to set upSimple and easy to set up Relatively inexpensive (less cable)Relatively inexpensive (less cable) Suitable for small, temporary networks Suitable for small, temporary networks

(gaming)(gaming)


Disadvantages of Bus NetworksDisadvantages of Bus NetworksDisadvantages of Bus NetworksDisadvantages of Bus Networks

Passive topologyPassive topology AttenuationAttenuation May require repeatersMay require repeaters A break in the cable…A break in the cable…


Ring NetworksRing NetworksRing NetworksRing Networks


Ring NetworksRing NetworksRing NetworksRing Networks

A bus network where the last computer in the A bus network where the last computer in the chain is connected back to the first computerchain is connected back to the first computer

Each computer is connected to two othersEach computer is connected to two others Signal travels in a circleSignal travels in a circle A physical ring network uses coax cableA physical ring network uses coax cable A logical ring network uses STP cable and A logical ring network uses STP cable and

complies with IEEE 802.5 specificationscomplies with IEEE 802.5 specifications


Communications on a Ring Communications on a Ring NetworkNetwork

Communications on a Ring Communications on a Ring NetworkNetwork

Communications happen in one directionCommunications happen in one direction Each computer receives the signal from its Each computer receives the signal from its

upstream neighbor and sends it to its upstream neighbor and sends it to its downstream neighbor.downstream neighbor.

Active topology because each computer Active topology because each computer regenerates the signal before passing it onregenerates the signal before passing it on

Token Ring architecture is generally a logical Token Ring architecture is generally a logical ring. Using a special hub – a multistation ring. Using a special hub – a multistation access unit (MSAU)access unit (MSAU)


Advantages of a Ring NetworkAdvantages of a Ring NetworkAdvantages of a Ring NetworkAdvantages of a Ring Network

Easy to troubleshootEasy to troubleshoot Simple to set upSimple to set up Requires less cable that a star networkRequires less cable that a star network


Disadvantages of a Ring Disadvantages of a Ring NetworkNetwork

Disadvantages of a Ring Disadvantages of a Ring NetworkNetwork

If the ring is broken, all network If the ring is broken, all network communications haltcommunications halt

Adding computers to the ring can be Adding computers to the ring can be problematicproblematic– The ring must be broken to add the new The ring must be broken to add the new

workstationworkstation


Star NetworksStar NetworksStar NetworksStar Networks


Star NetworksStar NetworksStar NetworksStar Networks

The most popular LAN topologyThe most popular LAN topology Each computer is connecter to a central hubEach computer is connecter to a central hub Hubs can be active passive or intelligentHubs can be active passive or intelligent

– Passive – a connection point, no electricityPassive – a connection point, no electricity– Active – boosts the signal before passing alongActive – boosts the signal before passing along– Intelligent – contains processing chip with Intelligent – contains processing chip with

diagnostic toolsdiagnostic tools UTP cabling and Ethernet 10BaseT or UTP cabling and Ethernet 10BaseT or

100BaseT architecture100BaseT architecture


Communications on a Star Communications on a Star NetworkNetwork

Communications on a Star Communications on a Star NetworkNetwork

Signal from the sending computers NIC to the Signal from the sending computers NIC to the hub, boosted, and sent back on all portshub, boosted, and sent back on all ports

All computers receive the messageAll computers receive the message All computers except the one who’s NIC All computers except the one who’s NIC

address matches the message header discard address matches the message header discard the messagethe message


Advantages of a Star NetworkAdvantages of a Star NetworkAdvantages of a Star NetworkAdvantages of a Star Network

Very fault tolerantVery fault tolerant Very flexibleVery flexible

– Easy to add workstationsEasy to add workstations

– Easy to reconfigure the topologyEasy to reconfigure the topology

– Easy to troubleshootEasy to troubleshoot


Disadvantages of a Star NetworkDisadvantages of a Star NetworkDisadvantages of a Star NetworkDisadvantages of a Star Network

CostCost– Lots more cable is requiredLots more cable is required

– HubHub


Mesh NetworksMesh NetworksMesh NetworksMesh Networks

Every computer on the network has a direct Every computer on the network has a direct connection to every other computerconnection to every other computer

AdvantagesAdvantages– The most fault tolerantThe most fault tolerant

– An alternate path exists between two computersAn alternate path exists between two computers DisadvantagesDisadvantages

– Very, very expensive – cable, NIC’sVery, very expensive – cable, NIC’s



A network where elements of the previous A network where elements of the previous network types are usednetwork types are used

Several hubs can be connected in a bus Several hubs can be connected in a bus topologytopology

Each hub however uses a star topology to Each hub however uses a star topology to connect several computers to the networkconnect several computers to the network


Categorizing Networks by Categorizing Networks by ArchitectureArchitecture


Includes a set of specifications that take into Includes a set of specifications that take into account its account its – Physical and logical topologiesPhysical and logical topologies

– The type a cable usedThe type a cable used

– Distance limitationsDistance limitations

– Media access methodsMedia access methods

– Packet size and headers Packet size and headers

– Other factorsOther factors




EthernetEthernet Token RingToken Ring AppleTalkAppleTalk ARCnetARCnet


Ethernet ArchitectureEthernet ArchitectureEthernet ArchitectureEthernet Architecture

Xerox, Digital, Intel (1960’s)Xerox, Digital, Intel (1960’s) IEEE 802.3 specificationsIEEE 802.3 specifications Bus or starBus or star Media access – CSMA/CD – carrier sense Media access – CSMA/CD – carrier sense

multiple access collision detectionmultiple access collision detection 10 Mbps, 100 Mbps (Fast Ethernet), 1 Gbps10 Mbps, 100 Mbps (Fast Ethernet), 1 Gbps


Subcategories of Ethernet Subcategories of Ethernet NetworksNetworks

Subcategories of Ethernet Subcategories of Ethernet NetworksNetworks

10Base510Base5 10Base210Base2 10BaseT10BaseT 100BaseT100BaseT 1000BaseT1000BaseT 100BaseVG-AnyLAN100BaseVG-AnyLAN 10BaseFL10BaseFL 100BaseFL100BaseFL


10Base2 Ethernet Networks10Base2 Ethernet Networks10Base2 Ethernet Networks10Base2 Ethernet Networks

•Uses thinner (approx. ¼-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


10BaseT Ethernet Networks10BaseT Ethernet Networks10BaseT Ethernet Networks10BaseT Ethernet Networks

•This 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


100BaseT Ethernet Networks100BaseT Ethernet Networks100BaseT Ethernet Networks100BaseT Ethernet Networks

•Refers to Ethernet networks running at 100 Mbps over Cat 5 or Cat 5e cable.

•Many NIC’s 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.


1000BaseT Ethernet Networks1000BaseT Ethernet Networks1000BaseT Ethernet Networks1000BaseT Ethernet Networks•Gigabit Ethernet Networks•This 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.


100BaseVG-AnyLAN Ethernet 100BaseVG-AnyLAN Ethernet NetworksNetworks

100BaseVG-AnyLAN Ethernet 100BaseVG-AnyLAN Ethernet NetworksNetworks

•This 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.


10BaseFL and 100BaseFL 10BaseFL and 100BaseFL NetworksNetworks

10BaseFL and 100BaseFL 10BaseFL and 100BaseFL NetworksNetworks

•FL 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.


Token Ring NetworksToken Ring NetworksToken Ring NetworksToken Ring Networks•This 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 802.5

•IBM 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.


AppleTalk NetworksAppleTalk NetworksAppleTalk NetworksAppleTalk Networks

•Protocol 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 resources

–AppleShare print server – Provides for sharing of printers

•AppleShare 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.


ARCnet NetworksARCnet NetworksARCnet NetworksARCnet Networks

•Attached Resource Computer Network

•Old 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.


Open Systems InterconnectOpen Systems InterconnectOpen Systems InterconnectOpen Systems Interconnect

OSIOSI– 19471947– 140 country members140 country members

International Organization for International Organization for Standardization (ISO) Standardization (ISO)

– Greek “isos” meaning equalGreek “isos” meaning equal DoD -> August 1990DoD -> August 1990 Protocol suite intended to Protocol suite intended to

replace TCP/IPreplace TCP/IP http://www.iso.ch/iso/en/http://www.iso.ch/iso/en/

ISOOnline.frontpageISOOnline.frontpage


OSIOSIOSIOSI

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


Layer 7 - The Application LayerLayer 7 - The Application LayerLayer 7 - The Application LayerLayer 7 - The Application Layer Programs which use services of the network Programs which use services of the network

reside in this layer. These programs are the reside in this layer. These programs are the ultimate consumer of network services of the ultimate consumer of network services of the lower layers. The transmission of messages lower layers. The transmission of messages used by these programs is the entire goal of the used by these programs is the entire goal of the lower protocols.lower protocols.


Layer 7 - The Application LayerLayer 7 - The Application LayerLayer 7 - The Application LayerLayer 7 - The Application Layer Examples of Application Layer programs are:Examples of Application Layer programs are:

Telnet.Telnet.

File Transfer Protocol FTP.File Transfer Protocol FTP.

SMTPSMTP

Network Filing System NFS (Sun).Network Filing System NFS (Sun).

SNMP (Simple Network Management Protocol)SNMP (Simple Network Management Protocol)

AppleShare (Apple).AppleShare (Apple).

Netx (Novell).Netx (Novell).

DOOM! (iD Software) :-).DOOM! (iD Software) :-).


Layer 6 - The Presentation Layer 6 - The Presentation LayerLayer


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




Examples of Presentation Layer protocols: Examples of Presentation Layer protocols: HTTP HTTP

Telnet Telnet

AppleTalk Filing Protocol AFPAppleTalk Filing Protocol AFP

E-mail gatewayE-mail gateway

Gateway Services for NetwareGateway Services for Netware

Systems Network Architecture gateway Systems Network Architecture gateway


Layer 5 - The Session LayerLayer 5 - The Session Layer Layer 5 - The Session LayerLayer 5 - The Session Layer This layer establishes connections or This layer establishes connections or

'conversations' between processes over the 'conversations' between processes over the network.network.

Examples of Session Layer protocols: Examples of Session Layer protocols: TCP TCP

Named Pipes Named Pipes

NetBIOS NetBIOS

Apple protocols ASP, ADSP, ZIP, PAP Apple protocols ASP, ADSP, ZIP, PAP


Layer 4 - The Transport LayerLayer 4 - The Transport Layer Layer 4 - The Transport LayerLayer 4 - The Transport Layer This layer provides methods of flow control, This layer provides methods of flow control,

ordering of received data, and ordering of received data, and acknowledgement of correctly received data.acknowledgement of correctly received data.

Ports and SocketsPorts and Sockets


Layer 4 - The Transport LayerLayer 4 - The Transport Layer Layer 4 - The Transport LayerLayer 4 - The Transport Layer Some examples of Transport Layer protocols Some examples of Transport Layer protocols

are: are: TCP TCP

User Datagram Protocol UDP User Datagram Protocol UDP

Netbios/NetBEUI Netbios/NetBEUI

Sequenced Packet Exchange SPX (Novell) Sequenced Packet Exchange SPX (Novell)

VINES Interprocess Communication Protocol VINES Interprocess Communication Protocol VIPCVIPC

DNS – Name Resolution DNS – Name Resolution


Layer 3 - The Network LayerLayer 3 - The Network Layer Layer 3 - The Network LayerLayer 3 - The Network Layer This layer provides to the upper layers a means of This layer provides to the upper layers a means of

transmitting "datagrams" over the network to a transmitting "datagrams" over the network to a specified host. This datagram service provides no specified host. This datagram service provides no confirmation of safe delivery of the information. The confirmation of safe delivery of the information. The transmissions are "connectionless" meaning that there transmissions are "connectionless" meaning that there is no "continuing conversation" set up between the two is no "continuing conversation" set up between the two hosts. One datagram may have nothing to do with the hosts. One datagram may have nothing to do with the next one, and indeed, may arrive out of order if they next one, and indeed, may arrive out of order if they are related.are related.

This layer is also responsible for assigning addresses to This layer is also responsible for assigning addresses to the hosts and routing packets between interconnected the hosts and routing packets between interconnected networks.networks.


Layer 3 - The Network LayerLayer 3 - The Network Layer Layer 3 - The Network LayerLayer 3 - The Network Layer Examples of network layer protocols are:Examples of network layer protocols are:

IP - the Internet Protocol IP - the Internet Protocol

IPX - a Novell Protocol IPX - a Novell Protocol

DDP - Datagram Delivery Protocol - an Apple DDP - Datagram Delivery Protocol - an Apple Protocol Protocol

DevicesDevicesRoutersRouters

Layer 3 switchesLayer 3 switches


Layer 2 - The Data-Link LayerLayer 2 - The Data-Link Layer Layer 2 - The Data-Link LayerLayer 2 - The Data-Link Layer

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



Two sub layersTwo sub layers– Media Access Control (MAC)Media Access Control (MAC)

physical addressing issuesphysical addressing issues

– Logical Link Control (LLC)Logical Link Control (LLC) Logical topologyLogical topology



Examples of implementations are:Examples of implementations are:IEEE 802.2 (LLC) IEEE 802.2 (LLC)

IEEE 802.3 IEEE 802.3

IEEE 802.5 (token ring) IEEE 802.5 (token ring)

PPP LCP (point to point protocol for serial links)PPP LCP (point to point protocol for serial links)

DevicesDevicesBridges Bridges

Layer 2 switchesLayer 2 switches


Layer 1 - The Physical LayerLayer 1 - The Physical Layer Layer 1 - The Physical LayerLayer 1 - The Physical Layer This layer defines the physical media upon which the This layer defines the physical media upon which the

host is communicating through the network. The host is communicating through the network. The physical medium can be coaxial cable, FDDI (fiber), physical medium can be coaxial cable, FDDI (fiber), RS232, or even RF. RS232, or even RF.

This layer defines the specifics of implementing a This layer defines the specifics of implementing a particular transmission medium. It defines the type of particular transmission medium. It defines the type of cable, frequency, terminations, etc. One may see the cable, frequency, terminations, etc. One may see the advantage of dividing network functionality into advantage of dividing network functionality into layers. The Physical layer could be changed to some layers. The Physical layer could be changed to some new technology as it is developed without affecting the new technology as it is developed without affecting the operation of upper layers, provided the inter-layer operation of upper layers, provided the inter-layer interfaces are implemented properly.interfaces are implemented properly.


Layer 1 - The Physical LayerLayer 1 - The Physical Layer Layer 1 - The Physical LayerLayer 1 - The Physical Layer Analog versus digital signalingAnalog versus digital signaling Baseband versus broadband technologyBaseband versus broadband technology Asynchronous versus synchronous Asynchronous versus synchronous

transmissiontransmission MultiplexingMultiplexing Does not add header information to packetDoes not add header information to packet NICNIC

– Network architectureNetwork architecture

– Media typeMedia type

– Bus architectureBus architecture


Layer 1 - The Physical LayerLayer 1 - The Physical Layer Layer 1 - The Physical LayerLayer 1 - The Physical Layer

Some examples of Physical Layer implementations:Some examples of Physical Layer implementations:Ethernet Ethernet

10Base2 10Base2

10BaseT 10BaseT

100baseT 100baseT

Token Ring Token Ring

Arcnet Arcnet

FDDI FDDI

wireless (e.g. FM) wireless (e.g. FM)


Web Sites For More InfoWeb Sites For More InfoWeb Sites For More InfoWeb Sites For More Info

http://www.netc.org/network_guidehttp://www.netc.org/network_guide http://cs.nmhu.edu/osimodelhttp://cs.nmhu.edu/osimodel http://www.freesoft.org/CIE/Topicshttp://www.freesoft.org/CIE/Topics http://www.gocertify.com/quizzes/osihttp://www.gocertify.com/quizzes/osi http://lovecraft.die.udec.cl/OS/UNIX/unix-hints-and-http://lovecraft.die.udec.cl/OS/UNIX/unix-hints-and-

hacks/19270033.htmhacks/19270033.htm http://www.pe.net/~rlewis/Resources/james.htmlhttp://www.pe.net/~rlewis/Resources/james.html http://www.randywanker.com/OSIhttp://www.randywanker.com/OSI http://www.itp-journals.com/http://www.itp-journals.com/

OSI_7_layer_model_page1.htmOSI_7_layer_model_page1.htm

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