bandwidth requirements | My Assignment Tutor

25/09/20171• Understand bandwidth requirements and impact on networkload.• Investigate bandwidth requirements, cost constraints andthroughput.• The significance of user requirements for quality systemdevelopment.• Discuss quality expectations and the concept of systemgrowth.• Discuss and analyse user feedback requirements forcontinuous system improvement.• Plan and design a network system with a developed casestudy and analyse if it is fit for purpose.• Design a networked system to meet a given specificationfor the case study selected.• Investigate: Suited to devices, suited to users, supportive oflifestyle desires, supportive of commercial requirements.• Justify the security requirements and quality of serviceneedsObjectivesOBJECTIVESLO3. Design efficient networked systems25/09/20172 When building a LAN that satisfies the needs of a small or mediumsized business, your plan is more likely to be successful if ahierarchical design model is used. Divided into discrete layers. Each layer has a specific purpose. Becomes modular – maintenance, performance. Interfaces with end devices. Routers, switches, bridges, wireless access points.  Provides a means of connecting and controlling whichare allowed to communicate on the network.devices 25/09/20173Aggregates (funnels) Access Layer traffic. Controls traffic flow with security or routing policies. Defines broadcast domains. Routing of VLANs (Virtual LANs). Must be capable of quickly forwarding large amounts of data. Smaller networks – collapsed model (Core and Distribution). High speed backbone of the network. Must be highly available and redundant. The core area can also connect to Internet resources.25/09/20174LogicalLayoutPhysicalLayoutScalabilityRedundancyPerformanceSecurityManageabilityMaintainability25/09/20175ScalabilityHierarchical Networks can be expanded easily.Redundancy at the core and distribution layers ensure availability.Redundancy25/09/20176Availability is the probability that the network willperform the required function without failure underdefined conditions for a defined period of time.RedundancyPower outageso UPS/generator capacityo UPS/generator switchover coverageo UPS generator managementTemperature fluctuationsNatural disastero Earthquakeo Floodo Hurricaneo Disaster recovery plan25/09/20177PerformanceLink aggregation and distribution and core layerswitches provide near-wire speed at all layers.25/09/20178SecurityPort security at the access layer and policies at the distribution layermake the network more secure.Consistency among switches at each layer makes management more simple.ManageabilityConfigurationsFunctionalityAdditional SwitchRapid Recovery25/09/20179MaintainabilityThe modular design allows a network to scale easily withoutbecoming over-complicated or burdensome.Just because a network is hierarchical, it doesn’t mean it’s well designed.Network Diameter:The number of devices that a packet has to cross before it reaches its destination.Bandwidth Aggregation:After the bandwidth requirements of the network are known, links between specificswitches can be aggregated or combined to provide higher bandwidth.Redundancy:The practice of providing multiple paths to a destination or multiple instances of adevice.25/09/201710Network Diameter: For PC1 tocommunicatewith PC3, thedata musttraverse 6intermediateswitches.  In this case, the network diameter is 6.  Each switch introduces some latency.  In a hierarchical network, network diameter is always going to be apredictable number of hops between the source and destination devices.BandwidthAggregation: Linkaggregationallows multipleswitch portlinks to becombined soas to achieve higher throughput between switches. The determining factor is using link aggregation isthe requirements of the user applications.25/09/201711 In a traffic intensive environment (Network), BandwidthAggregation is used to provide the aggregation of multiplephysical links, creating a single virtual link that carries thebandwidth sum (or close to the sum) of each physical link. Bandwidth aggregation is used to provide both performance andredundancy.Redundancy : Is one part ofcreating a highlyavailable network. Multiple linksbetweenswitchesor multiple devices. It can get expensive and most likely will not be done onthe access layer because of the cost and variety ofdevices. It is feasible at the distribution and core layers.25/09/201712A Converged Network is one where voice and videocommunications have been combined on a single datanetwork.Legacy Equipment:Until now, mainly feasible on large enterprise networks.Advanced Technology:More popular to medium and small sized businesses.Can be a difficult decision considering current investments intechnology.Benefit:Only one network to manage.25/09/201713New Options:You can now tie voice and video communications directlyinto an employee’s personal computer system. Software integrated on a PC eliminates an expensivehandset. Add a webcam and video conference.Matching Switches to Specific LAN FunctionsTraffic Flow AnalysisUser Community AnalysisData Stores and Data Servers AnalysisTopology DiagramsSwitch Features25/09/201714.Traffic Flow Analysis:The process ofmeasuring thebandwidth usageon a network andanalyzing the data.Performance tuning.Capacity planning.Hardware improvement decisions.User Community Analysis: The process of identifying various groupings of users and their impact onnetwork performance.25/09/201715Data Stores and Data Servers Analysis:When analysing traffic on a network, consider the location of thedata stores and data servers.Consider both client-server and server-server traffic..Topology Diagram:A graphical representation of a network infrastructure.Switch connections with port numbers.Aggregated ports and redundant paths.Identify configuration by switch name.Could contain user information.25/09/201716Switch Form Factors:When selecting a switch, you need to decide between Fixed configuration or modular configuration. Stackable or non-stackable. The switch form factor (physical size) is important depending upon where theswitch will be installed. Wiring closet with limited space. Computer room with free standing racks. Shelf in a central area.Fixed Configuration Switches:Fixed in their configuration.You cannot add features or options to the switchbeyond those that originally came with the switch.25/09/201717Modular Switches: Offer more flexibility. Typically come with different sized chassis that allow forthe installation of different numbers of modular line cards. The line cards actually contain the ports.Stackable Switches:Interconnected using a special backplane cable that provides highbandwidth throughput between the switches (Cisco StackWise). The stacked switches effectively operate as a single, larger switch. Desirable when fault tolerance and bandwidth availability are criticaland a modular switch is too costly to implement.25/09/201718 When selecting a switch for the access, distribution, or core layer,consider the ability of the switch to support:Port Density. Forwarding Rate. Bandwidth Aggregation Requirements.Port Density:Port density is the number of ports available on a singleswitch.24 Port48 PortVery high density.Catalyst 6500 – 1,000 Ports25/09/201719Forwarding Rate:Defines the processing capabilities of a switch by ratinghow much data the switch can process per second.If the switch forwarding rate is too low, it cannotaccommodate full wire-speed communication across allof its switch ports. A 48 port Gigabit switch is capable of switching 48Gigabits of traffic.Forwarding Rate: Access layer switches typically do not need to operate at full wirespeed because they are physically limited by their uplinks to thedistribution layer. Allows the use of: Less expensive, lower performing switches at the access layer. More expensive, higher performing switches at the distribution and corelayers, where the forwarding rate makes a bigger difference.25/09/201720Link Aggregation: As part of bandwidth aggregation, you should determineif there are enough ports on a switch to aggregate tosupport the required bandwidth.24 Port GigabitSingle Port – 1 GigabitBOTTLE NECKUp to 8 ports boundtogether to provide up to8 Gigabits.Power over Ethernet (PoE): Allows the switch to deliver power to a device over theexisting Ethernet cabling.Adds considerable cost to the switch.25/09/201721Layer 3 Functionality: Switches typically operate at Layer 2 of the OSI Model.Hierarchical NetworkPort SecurityVLANsFastEthernet/GigabitPoELink AggregationQuality of Service (QoS)25/09/201722Layer 3 SupportRedundant ComponentsQuality of Service (QoS)Layer 3 SupportVery High Forwarding RateGigabit/10 GigabitRedundant ComponentsLink AggregationQuality of Service (QoS)25/09/201723 AccessDistributionCoreBandwidth (Link) AggregationFastEthernet/Gigabit EthernetGigabit Ethernet/10 Gigabit EthernetHigh Forwarding RateLayer 3 SupportPort SecurityPower Over Ethernet (PoE)Quality of Service (QoS)Redundant ComponentsSecurity Policies/Access Control ListsVery High Forwarding RateVLANs ScalabilityNetworks that follow the hierarchical model can grow much larger withoutsacrificing control or manageability because functionality is localisedand potential problems can be recognised more easily. An example ofa very large scale hierarchical network design is the Public SwitchedTelephone Network.Ease of implementation A hierarchical design assigns clear functionality to each layer, therebymaking network implementation easier.Ease of troubleshootingBecause the functions of the individual layers are well defined, theisolation of problems in the network is less complicated. Temporarilysegmenting the network to reduce the scope of a problem also iseasier.PredictabilityThe behaviour of a network using functional layers is fairly predictable,which makes capacity planning for growth considerably easier. Thisdesign approach facilitates modelling of network performance foranalytical purposes.Protocol supportThe mixing of current and future applications and protocols is much easieron networks that follow the principles of hierarchical design becausethe underlying infrastructure is already logically organised.Manageability All the benefits listed here contribute to greater manageability of thenetwork.25/09/201724Burgess, M., 2003. Principles of Network and System Administration. 2nd ed.Chichester: John Wiley and Sons Ltd.Hallberg, B., 2005. Networking: A Beginner’s Guide. 4th ed. Osborne: Mcgraw-Hill.Limoncelli, T. & Hogan, C., 2001. The Practice Of System and NetworkAdministration. London: Addison-Wesley.Lowe, D., 2005. Networking All-In-One Desk Reference For Dummies. 2nd ed. NewYork: Hungry Minds Inc..Olifer, N. & Olifer, V., 2005. Computer Networks: Principles, Technologies AndProtocols For Network Design. Chichester: John Wiley And Sons Ltd.Stallings, W., 2003. Data And Computer Communications. 7th ed. New York:Prentice Hall.Subramanian, M., (2000). Network Management: An Introduction to Principles andPractice. Chichester: Addison-Wesley.Tanenbaum, A., 2002. Computer Networks. London: Prentice Hall Ptr.JournalsThe Institute of Engineering and Technology


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