1. Managing the mobile device wave:Best PracticesBRKEWN-2019

2. Session Objectives At the end of the session, the participants should be able to:Define High Client DensityUnderstand how to define the mobile application requirements in terms of bandwidth/clientUnderstand throughput characteristics of available wireless protocols (802.11b,g,a,n)Understand the RF challenges that come with High Client DensityUnderstand the available mitigation strategies that can be employed and how/when to apply themUse the knowledge gained to educate end customers and produce successful wireless deployments BRKEWN-2019 2011 Cisco and/or its affiliates. All rights reserved. Cisco Public 2 3. What Will be Covered Introduction Challenge Statement Key design criteria and conceptsRF Basics in dense environmentsBalancing signal against interference Available Design ElementsWireless protocols/capabilitiesFeatures - RRM, ClientLink, BandSelect, Antenna Selection, APs Practical application BRKEWN-2019 2011 Cisco and/or its affiliates. All rights reserved. Cisco Public 3 4. What Will Not be Covered Specific Applications and their Performance Wired side considerations and resource requirementsSecurity ServicesApplication server performance BRKEWN-2019 2011 Cisco and/or its affiliates. All rights reserved. Cisco Public 4 5. Why High Client Density? Mobility has rapidly changed how we use and what we expect ofwireless network resources Wireless is fast becoming the preferred option in edge technologyand in a lot of cases the only practical one The need to provide high performance wireless connectivity tolarge dense groups of clients exists today in auditoriums,classrooms, lecture halls, sporting arenas The same principles are becoming increasingly necessary intraditional coverage models due to the explosion of 2.4 GHz smartdevices and increasing connection counts per seat Application demands are increasing in this medium Even with the fantastic advances - wireless is still a shared HalfDuplex medium and requires efficient spectrum use to succeed. BRKEWN-2019 2011 Cisco and/or its affiliates. All rights reserved. Cisco Public 5 6. Design StepsDetermine Application Requirements Select Supported ProtocolsDetermine AP type And PlacementTune the ConfigurationBRKEWN-2019 2011 Cisco and/or its affiliates. All rights reserved. Cisco Public 6 7. Aggregate and Per-User Throughput 802.11, like Ethernet, is a shared medium Aggregate throughput is the total bandwidth shared by all users in acell Generally, the larger the cell, the more usersin the cellGreater per user throughput means smaller cells and more access points for a given area How many users per access point?Whats the aggregate throughput of the access point?On average, what amount of per user throughput do you need to provide? BRKEWN-2019 2011 Cisco and/or its affiliates. All rights reserved. Cisco Public 7 8. Per-User Application ThroughputexamplesTechnologyData Rate (Mbps)AggregateExample User Average perThroughput Countuser(Mbps)Throughput802.11b 117.210 720Kbps802.11b 117.220 360Kbps802.11b 117.230 240Kbps802.11b/g 5413 10 1.3Mbps802.11b/g 5413 20 650Kbps802.11b/g 5413 30 430Kbps802.11a 5425 10 2.5Mbps802.11a 5425 20 1.25Mbps802.11a 5425 30 833KbpsBRKEWN-2019 2011 Cisco and/or its affiliates. All rights reserved. Cisco Public 8 9. What about HT20 rates? What is your expected mix 14 Throuput of mixed 11a and 11n clients, with RTS-CTSof HT20 to legacy clients?100% 11n75% 11n50% 11n Few have the luxury of1225% 11n100% 11aestablishing and10maintaining a fixed Throughput of per client, Mbpsratio be sure 8 The delta between 100%6802.11n clients and 100%4legacy 802.11a clients is a312% increase/decrease2 A 50/50 mix however drops 0that advantage to 34%10 15 2025 30Number of clients3540 4550increase As user density increasesthe spread narrows BRKEWN-2019 2011 Cisco and/or its affiliates. All rights reserved. Cisco Public9 10. How Much Bandwidth is Required? Often, less than youd think It is most likely that you wont be Application by use Throughputsupporting just one application case Nominal Design for the highest bandwidthWeb - Casual 500 Kbpsdemand that you intend to support Web - Instructional1 MbpsWhat you really need here is the minimumAudio - Casual 100 Kbps acceptable throughput that the Audio - instructional1 Mbps application will requireVideo - Casual 1 MbpsIt is advisable to measure this yourself onmultiple platforms -Video - Instructional2-4 Mbpsmanufacturer/supplier numbers are goodPrinting 1 Mbps but Trust and Verify is always a bettercareer bet. File Sharing - Casual1 MbpsFile Sharing - Instructional 2-8 Mbps Multiply this number by the numberof connections/seats that you needOnline Testing 2-4 Mbpsto supportDevice Backups 10-50 Mbps This is the aggregate bandwidthyou will require in your space BRKEWN-2019 2011 Cisco and/or its affiliates. All rights reserved. Cisco Public10 11. Design StepsDetermine Application Requirements Select Supported Protocols Determine AP typeAnd Placement Tune the ConfigurationBRKEWN-2019 2011 Cisco and/or its affiliates. All rights reserved. Cisco Public 11 12. Channel Throughput by Protocol Protocol Throughput (Mbps) 802.11b7.2 802.11b/g mix13 802.11g25 802.11a25 802.11n (HT20 2ss MCS15) 70* If your application requires 3 Mbps then you can get 2 seats on802.11b or 4 seats on b/g mix 6 seats on a pure 802.11g channel or 802.11a This assumes that the channel is performing at peak efficiency* Two spatial streams note most PDAs are SISO (MCS 7) 35 Mbps max BRKEWN-2019 2011 Cisco and/or its affiliates. All rights reserved. Cisco Public 12 13. Points to Consider 3 non-overlapping channels in 2.4 GHz4 possible in EU/J with 1,5,9,13 14 12-21 non-overlapping channels in 5 GHz (checkyour regulatory domain) Not all clients will be able to use DFS channels or802.11n 100-140 least supported 802.11n APs will buy a lot of advantage for legacya/g clients In general treat 802.11n clients as a bonus and DoNot count on the number that will be able to use itunless you have certain knowledge of their presence 5 GHz will be critical to supporting High Density BRKEWN-2019 2011 Cisco and/or its affiliates. All rights reserved. Cisco Public 13 14. Cell Size by protocol / speedAssuming 10% PERSpeed Required SNR AP Sensitivity 1 0-91 2 3-915.56-91 6 2-8711 9-8812 6-8624 11 -853613-854817-785419-77Channel Utilization is the aggregate of every radio on the channel that can be heard above -85 dBm this means clients too.BRKEWN-2019 2011 Cisco and/or its affiliates. All rights reserved. Cisco Public 14 15. Channel Re-use The question is how many channels can I get in a room? Co-channel interference from Client Radios will be the singlebiggest obstacle- WHY?MCS Index ModulationMinimumRequired1/2/3 spatial SensitivitySNR (dB)stream20 MHz0/8/16BPSK 1/2-8211/9/17QPSK 1/2-7942/10/18 QPSK 3/4-776.53/11/19 16 QAM 1/2-749.754/12/20 16 QAM 3/4-70135/13/21 64 QAM 2/3-6617.256/14/22 64 QAM 3/4-6518.757/15/23 64 QAM 5/6-6419.75 *Assuming 10% PER BRKEWN-2019 2011 Cisco and/or its affiliates. All rights reserved. Cisco Public15 16. Data Rate and Performance Variance Data rates decrease with the increase of distance from the radio source and client power will increase Individual throughput (performance) varies with the number of users Performance degrades with radio interference from other sources Critical deployment design goal is to achieve high data rate at cell boundaryHigh signal AND low noiseBRKEWN-2019 2011 Cisco and/or its affiliates. All rights reserved. Cisco Public 16 17. What is CCA? 802.11 is CSMA/CA collision avoidance CCA is Clear Channel Assessment and is the listen before talkcomponent of Collision Avoidance With 802.11n radios CCA is typically linked to Preamble/Start ofpacket Radios are better (mostly) CCA - is -85 dBm for 802.11b/g/a If you can hear it above that you are sharing the spectrum BRKEWN-2019 2011 Cisco and/or its affiliates. All rights reserved. Cisco Public 17 18. Cell Isolation In a High Density Client environment, the APs will have the best viewof the room often line of site to the client (in overhead mounting) Client devices will be embedded with the users and result in a 10-15dB attenuation. This serves to reduce the overall interference radiusof the clients. Difficult to predict the radio dynamics affecting the client unless directmeasurements can be taken when space is filled. Very possible to focus on the AP and its view of the world andimprove downlink performance. The object is to make the network resilient by optimizing every aspectwithin our control BRKEWN-2019 2011 Cisco and/or its affiliates. All rights reserved. Cisco Public 18 19. Channel Efficiency Range versus rate is something that we are generally working tomaximize in a coverage design - However In High Density Design, the reverse is actually true we want tominimize the propagation of a cell Minimizing the cell size is a function of limiting the propagation, thereare 3 ways to do this1. Limiting supported rates2. Managing the power of the radios (AP and Client)3. Using the right antennas to shape both Tx and Rx cell size Properly applied, this will maximize channel re-use in a small space BRKEWN-2019 2011 Cisco and/or its affiliates. All rights reserved. Cisco Public 19 20. Duty Cycle and Spectrum Capacity Duty Cycle is the on time of a given transmitter It is measured as percentage of total time available, this relatesdirectly to channel utilization, but is only part of the story protocoloverhead is the full story 802.11 can only do essentially two things to recover in achallenging RF environmentRetransmit a Frame Turn the radio on again to send information that has already been sent once = Increased Duty CycleRate shift to a slower speed that can be supported If retries are excessive, then the link will be rate shifted to a slower speed in an attempt to gain reliability Both of these will increase Duty Cycle and make the problemworse if it is a dense network BRKEWN-2019 2011 Cisco and/or its affiliates. All rights reserved. Cisco Public20 21. Understand Protocol Selection 802.11 b/g/a/n andDuty CycleImportant? Why?2000018000160001400012000CCK DSSSOFDMTime/S 1000064 Byte 128 Byte 8000256 Byte 512 Byte 6000 1024 Byte 2048 Bytes 4000 2000Frame Size/Bytes0Mbps125.511 6122436 48 54 130 300 Spectrum is a Shared Finite ResourceBRKEWN-2019 2011 Cisco and/or its affiliates. All rights reserved.Cisco Public21 22. Duty Cycle and Spectrum 802.11 b/g Healthy Network 20-30% Duty Cycle Channel SeparationBRKEWN-2019 2011 Cisco and/or its affiliates. All rights reserved. Cisco Public 26 23. Duty Cycle and Spectrum 802.11 b/gUn-HealthyNetworkNo Channel Separation100% Duty CycleBRKEWN-2019 2011 Cisco and/or its affiliates. All rights reserved. Cisco Public 27 24. Channel UtilizationWhat Made the Difference?What MadeThis DramaticChange?Before5% After BRKEWN-2019 2011 Cisco and/or its affiliates. All rights reserved. Cisco Public 28 25. Every SSID Counts! Each SSID requires a separate Beacon Each SSID will advertise at theminimum mandatory data rate Disabled not available to a client Supported available to an associatedclient Mandatory Client must support inorder to associate BRKEWN-2019 2011 Cisco and/or its affiliates. All rights reserved. Cisco Public 29 26. Data Rate Cell SizeControlling Cell SizeBRKEWN-2019 2011 Cisco and/or its affiliates. All rights reserved. Cisco Public 30 27. 802.11b Scalability*11/7 Mbps*11/7 MbpsTotal offered Capacity = 21Mbps*11/7 Mbps* Data Rate/Throughput What if we added 3 more APs to this coverage area?BRKEWN-2019 2011 Cisco and/or its affiliates. All rights reserved. Cisco Public31 28. 802.11b/g mixed Scalability*54/13 Mbps*54/13 MbpsTotal offered Capacity = 39Mbps*54/13 Mbps* Data Rate/ThroughputBRKEWN-2019 2011 Cisco and/or its affiliates. All rights reserved. Cisco Public32 29. 802.11a Scalability US 5 GHz has 21Indoor Channels*54/25 Mbps*54/25 Mbps*54/25 Mbps*54/25 Mbps*54/25 Mbps 20Channels x25 Mbps*54/25 Mbps Total offered capacity =*54/25 Mbps 500 Mbps!*54/25 Mbps*54/25 Mbps* Data Rate/Throughput What about 11n? 9-bonded channelsBRKEWN-2019 2011 Cisco and/or its affiliates. All rights reserved. Cisco Public 33 30. Capacity Capacity is throughput multiplied by available, non-overlappingchannels802.11b and 802.11g operate in the same band, use the same three channels Any 802.11g capacity increase is from throughput alone 802.11a currently provides 12 to 23 channels in most of the worldWhile throughput might be similar to 802.11g, channels are not, neither then is capacity In theory, access points set to non-overlapping channels may be co-located to provide all available capacity in a single coverage areaMore commonly, its an expression of total throughput across a network or facility BRKEWN-2019 2011 Cisco and/or its affiliates. All rights reserved. Cisco Public 34 31. Receiver Sensitivity Example for 2.4GHz Direct Sequence Indication of the ability ofthe receiver to decode the desired signal The minimum receivedsignal level, in the absence of Receiver Sensitivity-87 dBm @ 11 Mbpsinterference, at which the desired signalcan be decoded with a particular BitError Receiver Sensitivity-90 dBm @ 5.5 MbpsRate (BER) Typically expressed in dBmReceiver Sensitivity-92 dBm @ 2 Mbps The more negative the value,Receiver Sensitivitythe better-94 dBm @ 1 Mbps Function of the data rate: the higher thedata rate, the higher the receiversensitivity required-98 dBm Receiver Noise Floor(Will Vary for EachEnvironment) BRKEWN-2019 2011 Cisco and/or its affiliates. All rights reserved. Cisco Public35 32. BandSelectAccess Point Assisted 5 GHz Band SelectionChallengeDual-Band clients persistently connect to 2.4 GHzDual-Band Client Radio 2.4/5GHz 2.4GHz may have 802.11b/g clients causingcontention 2.4GHz is prone to interferenceSolutionDiscoveryResponseBandSelect directs clients to 5 GHz optimizing RF Discovery Probesusage Looking for AP Better usage of the higher capacity 5GHz band2.45 Frees up 2.4 GHz for single band clients802.11n Optimized RF Utilization by Moving 5 GHz Capable Client Out of theCongested 2.4 GHz Channels BRKEWN-2019 2011 Cisco and/or its affiliates. All rights reserved. Cisco Public36 33. BandSelect Configuration Per-SSID Override ContdBRKEWN-2019 2011 Cisco and/or its affiliates. All rights reserved. Cisco Public 37 34. High Density Deployment High Density 5GHz office deployment 5GHz does not have the overlap or collision domain issues of 2.4GHz. 12APs on 1 floor36 48 60100132 149116 645244 10436BRKEWN-2019 2011 Cisco and/or its affiliates. All rights reserved. Cisco Public 38 35. 2.4 GHz Efficiency Eliminate Lowest supported ratesThere is no consistency between clients on when to rate shift and for how long. Eliminate support for this at the AP. Eliminate 802.11b all together if possibleEliminating all 802.11b rates removes the need for 802.11g protection mechanisms (CTS to self) and significantly improves efficiency Beacons will be transmitted at the lowest AP Mandatory rate A beacon will be sent for each supported SSID BRKEWN-2019 2011 Cisco and/or its affiliates. All rights reserved. Cisco Public 39 36. Design StepsDetermine Application RequirementsSelect Supported ProtocolsDetermine AP type And Placement Tune the ConfigurationBRKEWN-2019 2011 Cisco and/or its affiliates. All rights reserved. Cisco Public 40 37. Selection of APs The type of AP you select will have a large impact on the amount ofdata that you successfully deliver Any AP that you consider should at a minimum have diversityantennaes 802.11n APs in general provide improved performance for legacyclients 802.11n Clients get a huge benefit and relieve a lot of stress onbandwidth for legacy clients (140 mbps connections for 802.11n in 20MHz) In all cases Stock Omni antennas are the recommended approach BRKEWN-2019 2011 Cisco and/or its affiliates. All rights reserved. Cisco Public 41 38. Diversity On/Off 11b/g802.11b/gAverage Packet Deviation - Diversity On/Off14 Time in milli-seconds1210 On In Bound 8 Off In Bound 6 On Out Bound 4 Off Out Bound 2 0 In BoundIn Bound Out BoundOut Bound OnOffOn Off 802.11b/g 12.27472637 13.11258706 10.06935323 9.997711443BRKEWN-2019 2011 Cisco and/or its affiliates. All rights reserved. Cisco Public 42 39. 802.11a DiversityBRKEWN-2019 2011 Cisco and/or its affiliates. All rights reserved. Cisco Public 43 40. Antenna Theory and Antenna Gain A theoretical isotropic antennahas a perfect 360 vertical and horizontalbeamwidth This is a reference for all antennae Gain is equal in all directions The reception of good signalsGainand interference is the samein all directionsHigh Gain Omni-directional Antennae: More coverage area on thehorizontal elevation Energy level directly aboveor below the antenna willbecome lower There is no increase in transmitted energy with the higher gain BRKEWN-2019 2011 Cisco and/or its affiliates. All rights reserved. Cisco Public44 41. Higher Gain AP Antennas Provide BetterReception of Client Signals Even if the client has a lower transmit power than the AP Even if the client has a lower gain antenna than the AP Because the signal is focused to a certain coverage area The signal received at the radio will have better signalstrength because of the gain of the AP antenna In most cases the SNR will be better because the radio will not hear the signalsthat are not coming from the direction not covered by the antenna Reception gain has the samecoverage characteristicsas transmission gain BRKEWN-2019 2011 Cisco and/or its affiliates. All rights reserved. Cisco Public 45 42. Antenna Radiation Patterns Antenna choice plays a critical part in design for proper coverageBRKEWN-2019 2011 Cisco and/or its affiliates. All rights reserved. Cisco Public46 43. Antenna Options Product ID Description GainF/BA/E2.4 GHz 5.2 dBi Diversity pillar mount ant,RP-TNC AIR-ANT2452V-R=5.2 dBiN/A OmniConnectors2.4 GHz 3 dBi/5 GHz 4 dBi 802.11n dual band omniAIR-ANT2451NV-R=3 dbi/4 dBiN/A OmniantennaAIR-ANT2460NP-R=2.4 GHz 6 dBi 802.11n directional antenna6 dBi10 dB80/75AIR-ANT5160NP-R=5 GHz 6 dBi 802.11n directional antenna6 dBi>15 dB 65/65AIR-ANT2422SDW-R= 2.4 GHz 2.2 dBi Short white dipole antenna, Qty 1 2.2 dBiN/A OmniAIR-ANT5135SDW-R= 5 GHz 3.5 dBi Short white dipole antenna, Qty. 13.5 dBiN/A OmniAIR-ANT2440NV-R=2.4 GHz 4 dBi 802.11n Omni wall mount antenna4 dBi N/A OmniAIR-ANT5140NV-R=5 GHz 4 dBi 802.11n Omni wall mount antenna4 dBi N/A OmniBRKEWN-2019 2011 Cisco and/or its affiliates. All rights reserved. Cisco Public47 44. Ruggedized 11n Enterprise APs12503500e1260 BRKEWN-2019 2011 Cisco and/or its affiliates. All rights reserved.Cisco Public 48 45. Ceiling mount AP placementAP1140 SeriesAP3500 Series The design of the diversity omni 2.4 and 5 GHz antennas in the AP1140 and 3500 are optimized for ceiling mounting BRKEWN-2019 2011 Cisco and/or its affiliates. All rights reserved. Cisco Public 49 46. Modern Omni Antenna BehaviorBasic Omni design and caveatModern Cisco 802.11n AP elevation A lot goes into the antenna design RF Matters! BRKEWN-2019 2011 Cisco and/or its affiliates. All rights reserved. Cisco Public 50 47. AP Placement ConsiderationsMultipath Highly reflective environments Multipath distortion/fade is a consideration 802.11b most prone 802.11g/a better Things that reflect RFIrregular metal surfacesLarge glass enclosures/wallsLots of polished stoneBRKEWN-2019 2011 Cisco and/or its affiliates. All rights reserved. Cisco Public51 48. Theater - Auditorium Use Tripods andOmnis to mountAPs Illuminating fromthe cornersencourages cellseparation Antennaespointed up!BRKEWN-2019 2011 Cisco and/or its affiliates. All rights reserved. Cisco Public 52 49. Theater Lecture HallOverhead is optimal however using directional antennas can getyou where you need to beBRKEWN-2019 2011 Cisco and/or its affiliates. All rights reserved. Cisco Public 53 50. Small Sporting Event Illuminating fromthe sides focusesenergy near users The center is notlikely to needmuch connectivity Omni Patch, orwall mountedBRKEWN-2019 2011 Cisco and/or its affiliates. All rights reserved. Cisco Public54 51. Large Venue High Density 20K seats andup Divide the coveragearea into cells tosupport theapplication andanticipated numberof application users Use APs withDirectional Antennasto create WLAN cellswithin the seatingareas Use down-tilt tocontrol the verticalRF beam width Design and Install forboth 2.4 GHz and 5GHz support If dual-band APs areused, verify if PoE+switches are required Note: Where APs may be physically mounted into power the AP the stadium also effects capacity designBRKEWN-2019 2011 Cisco and/or its affiliates. All rights reserved. Cisco Public55 52. Example: Single Tier 322 Seats (red) 480 Seats (blue) One AP per section Dividing up the coverage area depends on where AP/Antennas may be mounted BRKEWN-2019 2011 Cisco and/or its affiliates. All rights reserved. Cisco Public 56 53. Example: Two-Tiered RF Design 1020 Seats 96 Deep 47 WideSeating sectionsin the lower bowlare served bydifferent AP BRKEWN-2019 2011 Cisco and/or its affiliates. All rights reserved. Cisco Public 57 54. Bowl Seating RF Cell Footprint Overlapping cellsshould use non-overlapping channels(shown is the use ofthe 3 non-overlapping channelsin the 2.4 GHzdomain) Use Radio ResourceManagement (RRM)to automatically setthe AP channel andpower Sub-dividing fanseating with anAP/DirectionalAntenna depends onwhere APs can bemounted and pointed BRKEWN-2019 2011 Cisco and/or its affiliates. All rights reserved. Cisco Public 58 55. Design StepsDetermine Application RequirementsSelect Supported Protocols Determine AP typeAnd Placement Tune the Configuration Tune the ConfigurationBRKEWN-2019 2011 Cisco and/or its affiliates. All rights reserved. Cisco Public 59 56. Managing the resulting RF Use RRM? YES! DCA will maintain channel plan with changing interference levels this is a good thing TPC Threshold to adjust power levels to the floorSet threshold higher for 5 GHzLower for 2.4 GHz Minimize cell foot print by eliminating lower data rates Maintain 20% cell overlap Highly recommend versions 6.0 or greater BRKEWN-2019 2011 Cisco and/or its affiliates. All rights reserved. Cisco Public 60 57. RRM Configurations data rates 5 GHz eliminate 6-9 Mbps 2.4 GHz eliminate 1,2,5.5,6,9 Mbps Mandatory, Supported, Disabled Whats it all mean If you can, eliminate 11 Mbps turns off 802.11b alltogether! BRKEWN-2019 2011 Cisco and/or its affiliates. All rights reserved. Cisco Public 61 58. DCA Settings Set DCA to Automatic Avoid Foreign AP interference Threshold for change can be managed buy changing to lowsensitivity 30 dBm improvement required for channel change Ensure DCA has run through startup BRKEWN-2019 2011 Cisco and/or its affiliates. All rights reserved. Cisco Public 62 59. TPC Threshold 5 GHz can be run much hotter than 2.4 GHz more channels Hotter 5 GHz signals will also encourage dual-band reluctant clients toprefer 5 GHz Power levels of 4-5 is generally what you will want for 5 GHz, 7 isacceptable for 2.4 GHz. Test your coverage and adjust BRKEWN-2019 2011 Cisco and/or its affiliates. All rights reserved. Cisco Public 63 60. TPC Min/Max power GUI configuration v. 6.1.n From the controller GUI select-Wireless=>802.11a/b=>RRM-TPC Note: Ensure you select apply in the upper right had corner of the screen to save. BRKEWN-2019 2011 Cisco and/or its affiliates. All rights reserved. Cisco Public 64 61. Client Link - The Problem Beam Strength Not Directed to Client802.11a/g802.11n802.11a/g Client Connection Not Optimized,Creates Coverage HoleBRKEWN-2019 2011 Cisco and/or its affiliates. All rights reserved. Cisco Public 65 62. The ProblemBeam Strength Not Directed to Client802.11a/g X Beam Strength 802.11n 802.11a/g Client Connection Not Optimized, Creates Coverage Hole BRKEWN-2019 2011 Cisco and/or its affiliates. All rights reserved. Cisco Public 66 63. The Solution Cisco Innovation: ClientLink802.11a/g802.11nIntelligent Beam Forming Directs Signal to Improve Performance and Coverage for 802.11a/g DevicesBRKEWN-2019 2011 Cisco and/or its affiliates. All rights reserved. Cisco Public 67 64. The Solution Cisco Innovation: ClientLink802.11a/gUp to 65% Beam FormingImprovement802.11nIntelligent Beam Forming Directs Signal to Improve Performance and Coverage for 802.11a/g DevicesBRKEWN-2019 2011 Cisco and/or its affiliates. All rights reserved. Cisco Public 68 65. Benefit #1: Higher Throughputper 11a/g DeviceUp to 65% Increase in Throughput13.6%No Connection Throughput vs. Distancewithout 87.7% ClientLink70.4% 89.5% Test: 802.11a/g device with 802.11n network Source: MiercomBRKEWN-2019 2011 Cisco and/or its affiliates. All rights reserved. Cisco Public 69 66. Benefit #2: Higher System CapacityUp to 27% Improvement in Channel CapacityChannel Util of 74.2% Channel Util of 45.2% Faster data transmission, less retries = more efficient use of RFchannel. Faster 11a/g transactions opens airtime for 11n devices, providingthem improved experienceTest: 802.11a/g device measured at 16 antenna orientations w/ 802.11n networkSource: Miercom BRKEWN-2019 2011 Cisco and/or its affiliates. All rights reserved.Cisco Public 70 67. Benefit #3: Reduced Coverage HolesHigher PHY Data Rates ClientLink DisabledClientLink EnabledLower Data Higher DataRates RatesSource: Miercom; AirMagnet 6.0 Iperf Survey BRKEWN-2019 2011 Cisco and/or its affiliates. All rights reserved. Cisco Public 71 68. Benefit #3: Reduce Coverage Holes (Cont.) Lower retry rates ClientLink Disabled ClientLink EnabledHigh Retry Rates Low Retry RatesSource: Miercom; AirMagnet 6.0 Iperf SurveyBRKEWN-2019 2011 Cisco and/or its affiliates. All rights reserved. Cisco Public72 69. Beam Forming Enhancements Beam Forming will improve performance only when data rates begin to fallTranslation: If the connection is already good (i.e. data rate of 54Mbps) there is no improvement Measureable advantages:Increased SNR at cell edges ProvidesIncreased downstream data rates at cell edgesProvides Increased downstream throughput at cell edgesBRKEWN-2019 2011 Cisco and/or its affiliates. All rights reserved. Cisco Public 73 70. Load Balancing ConceptMaxMax Load LoadMinMin New ClientJoining NetworkBRKEWN-2019 2011 Cisco and/or its affiliates. All rights reserved. Cisco Public74 71. Load Balancing in Action Packet CaptureAP is loaded. AssociationAssociation AllowedDeniedBRKEWN-2019 2011 Cisco and/or its affiliates. All rights reserved. Cisco Public 75 72. Load Balancing Implementation The threshold to start load balancing is configured as a number of clients Association denied (Code 17) frames will be sent to clients who attempt to associate to loaded APs If the client does not join a different AP, the loaded AP will allow the client to associate after a number of retries (default is 3) Configured on a per-controller basis at a global levelCan be overridden for specific WLANsBRKEWN-2019 2011 Cisco and/or its affiliates. All rights reserved. Cisco Public 76 73. Load BalancingConfigurationWLC(Cisco Controller) >config load-balancing aggressive enableWARNING: Allowing load balance may impact time sensitive application like VOICEContinue? (y/N)y(Cisco Controller) >show load-balancingAggressive Load Balancing........................ EnabledAggressive Load Balancing Window................. 5 clientsAggressive Load Balancing Denial Count........... 3StatisticsTotal Denied Count...............................0 clientsTotal Denial Sent................................0 messagesExceeded Denial Max Limit Count..................0 timesNone 5G Candidate Count..........................0 timesNone 2.4G Candidate Count........................0 times BRKEWN-2019 2011 Cisco and/or its affiliates. All rights reserved. Cisco Public77 74. Load BalancingConfiguration Per-SSID Override Load Balancing can introduce latency in the association and roamingprocess This latency is harmless for data applications but can negatively impactreal-time applications. Recommendation: Disable load balancing for WLANs that handlereal-time applications such as voice and video Example Below disable load balancing for a specific WLANWLC(Cisco Controller) >config wlan disable 2(Cisco Controller) >config wlan load-balance allow disable 2(Cisco Controller) >config wlan enable 2(Cisco Controller) >show wlan 2 WLANIdentifier.................................. 2Network Name (SSID).............................. NoLoadBalanceLoad Balancing................................... Disabled BRKEWN-2019 2011 Cisco and/or its affiliates. All rights reserved. Cisco Public 78 75. Load Balancing Caveats Load balancing only occurs amongst APs on the same controller Load balancing requires that the client respect the Code 17 association response and act accordingly Load Balancing only occurs at initial association, not on re-association. Some older clients simply ignore the Code 17 response and try and associate again. Known clients that load balance correctly:Intel 4965AGN (with 12.1 or later drivers)Cisco CB-21AG (with 4.2 or later drivers)BRKEWN-2019 2011 Cisco and/or its affiliates. All rights reserved. Cisco Public 79 76. More Information Cisco 802.11n Design and Deployment Guidelineshttp://www.cisco.com/en/US/solutions/collateral/ns340/ns394/ns348/ns767/white _paper_80211n_design_and_deployment_guidelines.html ClientLink Whitepaper:http://www.cisco.com/en/US/prod/collateral/wireless/ps5678/ps1 0092/white_paper_c11-516389.html ClientLink Miercom Report:http://www.cisco.com/en/US/solutions/collateral/ns340/ns394/ns 348/ns767/Miercom_Test_Report_Cisco_ClientLink.pdfBRKEWN-2019 2011 Cisco and/or its affiliates. All rights reserved. Cisco Public 80 77. BRKEWN-2019Recommended Reading BRKEWN-2019 2011 Cisco and/or its affiliates. All rights reserved. Cisco Public 81 78. Housekeeping We value your feedback- dont forget to completeyour online session evaluations after each session& complete the Overall Conference Evaluationwhich will be available online from Thursday Visit the World of Solutions Please remember this is a non-smoking venue! Please switch off your mobile phones Please make use of the recycling bins provided Please remember to wear your badge at all timesBRKEWN-2019 2011 Cisco and/or its affiliates. All rights reserved. Cisco Public 82 79. BRKEWN-2019 2011 Cisco and/or its affiliates. All rights reserved. Cisco Public 90