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Structured BackboneDesignof Computer Networks
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Structured Backbone Designof Computer Networks
Department of Computer Engineering
College of Computer Sciences & Engineering
King Fahd University of Petroleum & Minerals
Dhahran, Saudi Arabia
Computer Networks -- February 17 - 21, 2001
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Atef J. Al-Najjar
Enterprise Networks
lAn Enterprise Networks is aninterconnected collection of Local AreaNetworks (LANs).
»Several LANs
–Hubs, Chassis Hubs, Stackable Hubs, Bridges,(Workgroup) Switches
–Horizontal cabling
»Backbone
–Core routers and switches
–Vertical cabling
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Atef J. Al-Najjar
Structured Networks
lA Enterprise Network should be
»Logically structured
–Has a layered communication structure: Localaccess layer, distribution layer, and backbonelayer.
»Physically structured
–Topology is a hierarchical tree, with thebackbone at the root of the tree.
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Atef J. Al-Najjar
Logically Structured Networks
lLocal Access Layer
»Provides most convenient network access to theusers.
lDistribution Layer
»Provides policy-based network access to theworkgroup. This is where packet manipulationtakes place.
lBackbone Layer
»Provides high-speed seamless transport of dataamong the workgroups.
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Atef J. Al-Najjar
Enterprise Network Example
Token Ring
Ethernet
Ethernet
Backbone
Backbone Router
Ethernet Hub
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Atef J. Al-Najjar
Layer 3 Forwarding Requirement
lNumber of subnets x Subnet speed xPercent of inter-subnet traffic
lExample:
»50 x 100 Mbps x 0.2 = 1 Gbps
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Atef J. Al-Najjar
Structured Backbones
lModern organizations have
»Large networks
»Complex communication requirements
–Access to mainframe data
–Internetworking of several LANs
–Connectivity to a WAN (the Internet)
–Transmission of data and non-data
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Atef J. Al-Najjar
Backbone Basics
lComplex requirements mandated thestructuring of enterprise-wide informationdistribution.
lSuch structuring is effectively achievedthrough a system called Backbone.
lStructured wiring combined withBackbone solution provide a powerfuland efficient networking solution tocompany-wide communication needs.
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Backbone Basics (Contd.)
lKey Factors in assessing networktopologies:
»Performance
–Highest network availability.
–Lowest latency.
–Most appropriate connectivity for users.
»Scalability
–Ability to expand the network in terms of end-points and aggregate bandwidth withoutaffecting existing users.
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Atef J. Al-Najjar
Backbone Basics (Contd.)
»Cost of administration:
–The inherent ease of moves, adds, andchanges, plus the capability to efficientlydiagnose, remedy, or prevent network outages.
lStructured Backbone solutions offer
»Flexibility
»Scalability
»Troubleshooting & Manageability
»Performance
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Atef J. Al-Najjar
Structured Cabling
lCabling plan should be easy to:
»implement, and
»accommodates future growth.
lTwo standards have been issued thatspecify cabling types and layout forstructured commercial buildings wiring.
lA network should follow a cabling plan:
»Selection of cable types
»Cable layout topology
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Atef J. Al-Najjar
Structured Cabling Standards
lEIA/TIA-568: Issued jointly by theElectronic Industries Association and theTelecommunications Industry Assoc.
lISO 11801: Issued by the InternationalOrganization for Standardization.
lBoth Standards are similar.
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Atef J. Al-Najjar
Structured Cabling (Cont.)
lIt is a generic wiring scheme with thefollowing characteristics:
»Wiring within a commercial building.
»Cabling to support all forms of informationtransfer.
»Cable selection and layout is independentof vendor and end-user equipment.
»Cable layout designed to encompassdistribution to all work areas within thebuilding (relocation wouldn’t need rewiring).
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Atef J. Al-Najjar
Structured Cabling (Cont.)
lBased on the use of a hierarchical star-wired cable layout.
»External cables terminate at EquipmentRoom (ER).
»Patch panel and cross-connect hardwareconnect ER to Internal Distribution Cable.
»Typically, first level of distribution consistsof Backbone cables.
»Backbone cable(s) run from ER to TelecomClosets (Wiring Closets) on each floor.
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Atef J. Al-Najjar
Structured Cabling (Contd.)
»Wiring Closet contains cross-connectequipment for interconnecting cable on asingle floor to the Backbone.
lCable distributed on a single floor iscalled Horizontal Cabling, and connectsthe Backbone to Wall Outlets thatservice individual telephone and dataequipment.
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Atef J. Al-Najjar
Structured Cabling (Cont.)
lBased on the use of a hierarchical star-wired cable layout.
External
Cable
Telecom.
Closet
Equipment
Room
Backbone
Horizontal
Cable
Work
Area
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Atef J. Al-Najjar
Structured Cabling Terminology
Backbone
A facility between telecommunicationsclosets or floor distribution terminals, theentrance facilities, and the equipmentrooms within or between buildings
Horizontal Cabling
The wiring/cabling between the telecom
outlet and the horizontal cross-connect
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Atef J. Al-Najjar
Terminology (Cont.)
Cross-Connect
A facility enabling the termination of cableelements & their interconnection, and/orcross-connection, primarily by means of apatch cord or jumper
Equipment Room
A centralized space for telecom equip.tthat serves the occupants of the building(Bldg/Campus distributor in ISO 11801)
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Terminology (Cont.)
Telecommunications Closet:
An enclosed space for housing telecomequip.t, cable terminations, and cross-connect cabling; the location for cross-connection between the backbone andhorizontal facilities
Work Area
A building space where the occupantsinteract with the telecom terminal equip.t
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Terminology (Cont.)
Main Cross-Connect
A cross-connect between 1st and 2ndlevel backbone cables, entrance cables,and equipment cables (no ISO name)
Intermediate Cross-Connect
A cross-connect between 1st and 2ndlevel backbone cabling (no ISO name)
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Terminology (Cont.)
Horizontal Cross-Connect:
A cross-connect of horizontal cabling toother cabling, e.g. horizontal, backbone,or equipment (no ISO name)
Telecommunications Outlet
A connecting device in the work area onwhich horizontal cable terminates
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Media Recommended
Telecomm.
Outlet
Horizontal
Cross-connect
Main
Cross-connect
Intermediate
Cross-connect
Telecomm.
Outlet
Horizontal
Cross-connect
A
C
B
D
D
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Atef J. Al-Najjar
Cable Distances
lUTP (Voice Transmission)
MC-HC HC-ICMC-ICTO-HC
A BC D
800m500m 300m90m
lCat 3 or 5 UTP (up-to 16 or 100 MHz),
and STP (up-to 300 MHz)
A BC D
90m90m 90m90m
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Atef J. Al-Najjar
Cable Distances (Contd.)
l62.5 microns Fiber
MC-HC HC-ICMC-ICTO -HC
A BC D
2000m500m 1500m90m
lSingle-Mode Fiber
A BC D
3000m500m 2500m90m
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Unstructured Backbone -- Mainframe
Terminals
Mainframe
...
...
...
Cluttered
and noisy
cable risers
.
.
.
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Unstructured Backbone -- LAN
Each station must be physically connected by a thick coaxtapped to the LAN coax, running by all stations.
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Structured Backbone
lBy using a MUX or similar device, abackbone can be structured.
»A single fiber pair replaces mounds of coaxcable, and
»floor-to-floor traffic is systematicallyorganized.
lWith Structure comes enhanced
»network control
»reliability, and
»efficiency.
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Structured Backbone (Contd.)
lStructured backbone = structured,hierarchical physical star wiring scheme.
Mainframe
MUX
MUX
MUX
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Structured Backbone(Contd.)
lThe first information backbone emergedin the mid 1980’s.
lAn enterprise backbone is an aggregatedata path (a central communicationhighway) for the transport of all signalsto / from users distributed throughout theenterprise.
lEarly backbones were mainly muxes.
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Atef J. Al-Najjar
Structured Backbone(Contd.)
lThe enterprise network is usuallycomprised of three main parts:
»The horizontal access portion:
Connecting individual workstations to wiring
closets and most often accomplished via an
intelligent cabling Hub.
»The Backbone portion:
Facilitating floor-to-floor or building-to-building
connectivity.
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Structured Backbone (Contd.)
»The Wide Area Network link
Horizontal
access
Backbone
WAN
Interface
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When are Backbones needed?
lCompanies utilizing Backbone technologyhave typically one or more of the followingcommunication needs:
»Multiple data protocols and signals.
»Heavy network traffic to be supportedsimultaneously.
»Multiple work-groups, networks, and facilitiesthat need to be internetworked.
»Mission critical applications where highreliability and security are mandatory.
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Atef J. Al-Najjar
When are Backbones needed? (Contd.)
»Need to support varying media and devicetypes.
»A high degree of upgrade-ability, so thatexisting equipment can be preserved andhigher performance hardware and softwaresolutions can be implemented seamlessly.
»A high degree of network moves, adds, andchanges, requiring that the enterprisenetwork be highly manageable.
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Atef J. Al-Najjar
Types of (private) Backbones
Three broad categories:
(1) Multiplexers-based.
(2) LAN Backbones.
FDDI, Ethernet, Token Ring, etc
(3) Collapsed Backbones.
High-speed Router, Switches, ATM.
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Backbone Topologies
lStar
»Collapsed Backbone
»PBX system
»Switch-based networks
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Backbone Topologies (Contd.)
lRing.
»Ex: FDDI.
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Atef J. Al-Najjar
Backbone Topologies (Contd.)
lHierarchical/Inverse Tree.
Higher power at higher levels.
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Backbone Topologies (Contd.)
lMesh.
Multiple data paths between peer stations.
Topology relies on the use of Routers.
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Backbone Benefits
+ Makes complex distributed computingenvironment easier to manage.
+ Allows Organizations to easily upgradethe system.
+ Creates an integrated communicationpath capable of accommodating theenterprise’s data transfer requirementssafely and cost effectively.
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Atef J. Al-Najjar
Fiber Optics
lMany of the Backbone advantages areenabled by the implementation of fiber.
lAdvantages of fiber:
+ Ability to combine data, voice & videosignals over a single fiber pair.
+ Very large bandwidth: (allows large numberof users, is cost effective and space-conservative).
+ Increased data security & reliability.
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Fiber in the Backbone
lAll Backbone solutions are based on theuse of fiber because fiber:
»Forms the bases for all future Backbonemigrations.
»Enables network managers to extend thelife of their cabling plants.
»Enables the network to easily migrate tobetter technology (network applicationsoftware or network hardware).
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Application / Bandwidth
lHigh capacity Backbone is a must tosupport increasing need for bandwidth.
ApplicationBandwidth
Digital audio1.4 Mbps
Compressed video (JPEG)2 - 10 Mbps
Document Reprographics20 -100 Mbps
Compressed broadcast-quality TV20 -100 Mbps
High-definition full motion video1 - 2 Gbps
Chest X-Ray4 - 40 Mbps
Remote query burst1 Mbps
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Atef J. Al-Najjar
Get Connected
lUse your mouse
lUse your phone
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lSelect the bestspeed (Can be aTurtle!)
