Fast Innovation requires Fast IT

Transcription

1 Fast Innovation requires Fast IT

2 High Density & High Availability in Wireless Deployment MinSe Kim, Sr. Technical Marketing Engineer, Cisco Systems

3 Agenda WiFi Operation Today WLAN RF Design Fundamental Physical AP Placement Tips Configuration Best Practices Wired-Wireless Integration for HD WiFi 3

4 WiFi operation Today

5 Why High Density Wi-Fi? Wireless has become the preferred access technology -- and in many cases the only practical one The need for high density started with stadiums and auditoriums but has reached every network The explosion of smart devices and increasing connection counts per seat are everywhere Application demands are increasing Even with advances - wireless is still a shared half-duplex medium and requires efficient use to succeed. 2 to 3 devices per user

6 What are Some Typical Challenges? Interference from other WiFi networks in the venue Interference from non-wifi systems operating in the same band Co-channel interference: Many APs in the venue, but effectively no more capacity Clients operating at low data rates (ex b) pull down the performance of the network Clients mistakenly choose a 2.4 GHz radio (louder signal) instead of 5 GHz (less load) Sticky Clients: Clients mistakenly stay on the same AP, even when person has moved from one end of the venue to another Limitations on AP installable location. Hard to put APs where you want them Probe storms: 2.4 GHz clients probe on all 11 overlapping channels

7 Signal Quality Inevitable Interference from neighboring WiFi or from unknown sources Interference from Neighboring WiFi is impacting user experience Interference from Non-WiFi is also increasing 5GHz adoption is progressing but still less then 50% Neighboring AP is going louder and louder everyday

8 Signal Quality Issue Higher Tx Power means better coverage? Not always. Balanced link (make LinkBudget between UL and DL to be as closest as possible) provides most reliable performance WiFi coverage characteristic is determined by uplink link budget (Handset dependent) Max. Tx Power per antenna Number of Tx chain Number of Rx chain Ant. Gain (Omni) # of Tx:Rx antenna Cisco AP dbm 3 TX 4 RX 4 dbm 3:4 Cisco AP dbm 4 TX 4 RX 4/7 dbm 4:4 iphone 5 20 dbm 1 TX 1 TX -1.5 dbm 1:1

9 Designing for Efficient RF Relationships AP to Client How clients hear AP s Client to AP How AP s hear clients AP to AP How AP s hear each other 9

10 Balanced Link budget for Better Quality, Loadbalanced link Differences in Rx Sensitivity and Tx Power makes client to deem out of coverage AP as closer then what it actually located. Hence, Client roaming is not occurred, User exposed many problem Load Balancing doesn t work Roaming involves service outage. Increasing Packet Loss Network throughout drop -84 dbm, Seriously?! Come on- You need to roam! AP s perspective on iphone-a coverage RSSI for Client-1 : -84 dbm AP1 30 dbm EIRP from AP -76 dbm! RSSI s still okay!..i ll stay here 22.5d Bm EIRP Client-1 from iphone RSSI for AP-1 : -73 dbm AP2

11 RRM Radio Resource Management for Maximize RF design Radio Resource are scarce, interference prone and dynamically changes What do expect from RRM Control Tx Power TPC(Transmit Power Control), Coverage Hole Detection Dynamic Adaptive Channel Change DCA (Dynamic Channel Assignment), ED-RRM, DFS(802.11h) WLC as control center of RRM TPC (Transmit Power Control) Analyze AP-to-AP Neighboring RSSI value, overlap amount, Tx power and REDUCE AP Power DTPC*( Distrubuted Transmit Power Control) AP command client to reduce its power CHD (Coverage Hole Detection) AP check terminal s Uplink RSSI value. if Client is connecting from fringe, increase AP s power DCA (Dynamic Channel Assignment) AP scans entire channel, and select best channel. Can cause client dis-connect

12 802.11n Myth What we hear from the industry 802.1n will deliver 300Mbps, 450Mbps, 600Mbps 900 Mbps So Can WLC get chocked up as WLC will become bottleneck? Most of n supported Mobile device Supports 20Mhz, Long Guard Interval Single Tx / Rx Max Datarate = 65Mbps 98% of mobile device until Mid % Datarate increase from a/g Oversubscription is between downlink-uplink is typical in wired design (100Mbps x 24 : 1Gbps 24 Gbps x 20 : 2-20Gpbs) Required Network performance is application driven, not device driven

13 Mobile device WiFi Max Data rate Galaxy S Galaxy S4 iphone Samsung 200 Galaxy S iphone 1 iphone 3G iphone 3GS iphone 4 iphone 4s iphone 5 iphone 5s iphone 6

14 Client Association Storm In Subway Station, hundreds to thousand people can flood in/out Delay should be minimized, and immediate IP address assignment should happen Cisco s Association rate (CPS) 8500 WiSM2 vwlc Open WPA2 (EAP) Cisco DHCP Server(CNR) can assign 47,000 IP address in a seconds

15 Link Reliability during the roam Roaming must includes handoff and message exchange between AP-to-Client, between AP-to-AP Cisco Device support Caveats OKC Yes Windows Limited to few Android device Sticky Key Caching (802.11i) Yes Apple, Android Scalability issue r Yes Apple ios 6.0+ Can cause Legacy interoperability CCKM Yes CCX compatible device (eg. Samsung Galaxy S3) Limited support on Mobile device Average Roaming delay 0.5 sec 0.5 sec 0.1 sec 0.1 sec

16 WLAN RF Design Fundamental

17 Spectrum Intelligence Dedicated hardware chipset for monitoring spectrum Identifies interferer signatures by penetrating beyond Layer 1 (Records pseudo MAC address to avoid duplication) Quick and Accurate Interference Detection to Reduce False Positives Aggregation of all alarms/ alerts on Prime level to monitor health of entire network

18 Channel Utilization What Made the Difference? 60% Before 5% After 18

19 Maximize the Spectrum Leveraging PHY Rate Tuning Size your cells to allow elimination of low rates (i.e., <12mbps) Eliminate 11b rates Recommend NOT disabling any MCS rates due to interoperability issues with some clients Disabling MCS rates, especially 0-7, can cause significant client issues 19

20 Cell Size Depends on Protocol and Rates 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 boundary High signal AND low noise 20

21 Cell Size Higher Power Larger Coverage Higher power does not always mean higher SNR Assuming 10% PER Speed Required SNR AP Sensitivity This for data, for voice, add 25 db to SNR 21

22 CLIENT LINK Client Link 3.0 ClientLink uses multiple transmit antennas to focus transmissions in the direction of the client In the mixed-client networks, optimizes overall network capacity by helping ensure that a/g/n and ac clients operate at the best possible rates, especially when they are near cell boundaries. Client agnostic since Multiple Antennas Design Work for All Clients n ac AP ac n Wireless AP ac n

23 256QAM Heat Map: Cisco 3702i vs. Competition ClientLink 3.0 helps the 3700 achieve 256 QAM with m9 rate AP 3700 has a significant 256 QAM advantage over the competition 11ac AP The Test: Use a MacBook Pro (3ss) and record the data rate in 40+ locations in a cubicle environment while running traffic to the client. Cisco AP 3700 Heatmap Competitor AP Heatmap ClientLink 3.0 YouTube video:

24 Channel Coverage Sizing Recommendations Coverage must be designed for your Client Devices Not all clients are created equal!!! 1. Live call test with the actual client to determine its coverage Removing legacy DSSS data rates and slower OFDM data rates from the WLC configuration equals: 1. Less Co-Channel Interference 2. Better throughput in the cell 3. More usage of ClientLink and MRC 4. Smaller coverage cells Smaller Coverage Cell Sizes equals: 1. More cells in a given coverage area 2. More cells equals more call with better voice and video quality 24

25 Physical AP Placement Tips - Hospitality Case

26 Today WiFi in Hospitality CHALLENGES WiFi is the top guest issue Inconsistent experience across hotels Limited intelligence on guest behavior Free Wi-Fi is a guest expectation No enterprise class network management tools Current solutions do not support enhanced applications and service innovation SOLUTIONS Deliver consistent guest connectivity cost effectively Opportunity to monetize Wi-Fi Enhance experience through personalized mobile engagement (indoor maps with featured attractions; promotions) Visibility into where guests are moving/dwelling Encouraged use of loyalty app; credit card through mobile services and promotions

27 Hospitality WiFi Traditional Design

28 Hospital WiFi with Intelligent AP: Full Mobility Auto RF Dual Band 11n/ac WLC: Centralized Config/FW mgmt Web-based User Auth End-to-End Security

29 AP Mounting Orientation Incorrect AP Orientation Correct AP Orientation Best Practice Place APs pointing down for APs with internal antenna

30 Internal antenna version Access Points Designed for Horizontal Mounting Internal antenna versions of Access Points work best when mounted horizontally on the ceiling

31 AP Antenna Vertical coverage Ceiling RF Radiation is focused to downward direction

32 Installation use case To maximize AP s performance, AP installation location is highly recommended at ceiling mount as exposed. If customer must install AP inside ceiling, customer can consider external antenna model. External Antenna with AP inside ceiling

33 Where is the best location to place AP?

34 Bad AP Placement : AP around corner At A the phone is connected to AP 1 A 1 B C 3 2 At B the phone has AP 2 in the neighbor list, AP 3 has not yet been scanned due to the RF shadow caused by the elevator bank At C the phone needs to roam, but AP 2 is the only AP in the neighbor list The phone then needs to rescan and connect to AP B 54 Mbps is sent in 3.7 μs 200 B 24 Mbps is sent in 8.3 μs Rate shifting from 54 Mbps to 24 Mbps can waste 1100 μs 34

35 Good AP Placement AP on Intersection A 1 B 2 C At point A the phone is connected to AP 1 At point B the phone has AP 2 in the neighbor list as it was able to scan it while moving down the hall At point C the phone needs to roam and successfully selects AP 2 3 The phone has sufficient time to scan for AP 3 ahead of time 35

36 Avoid Reflections Highly reflective environments Multipath distortion/fade is a consideration Legacy SISO technologies (802.11a/b/g) are most prone n improvements with MIMO Devices are susceptible Things that reflect RF Irregular metal surfaces Large glass enclosures/walls Lots of polished stone 36

37 AP Placement in Hallways Incorrect AP Placement Correct AP Placement Best Practice Place APs within the Room

38 AP Placement in Multi-story Building Incorrect AP Placement Correct AP Placement Best Practice Place APs in Zig-Zag on Alternate Floors

39 WiFi Best Practices

40 General RF/AP Recommendations Disable low-speed 2.4 GHz data-rate 5GHz Channel width - 20MHz for capacity, 40Mhz for peak throughput. Place AP on Intersection, Exposed, Ceiling mount Leave front of AP as open space, avoid metal structure in front of AP Auto RF will provide optimal Channel and AP Tx Power,with Groupbased customization ac in spaces with high device density

41 HD Wi-Fi -- Best Practices Solid RF Design Broadcast SSID Constrain RF Directional Antennas, Down-Tilt Good RF Layout/Design: Channels, Tx Power Eliminate Interference Rogues and Non-Wi-Fi Interference Basic Tuning Minimize SSIDs Disable Low Data Rates Helps with Sticky Clients, Improves capacity Band Select Push dual-band clients to 5 GHz Load Balancing Advanced RF Profile Group-based policy Rx-SOP Tuning Greatly improves capacity by reducing co-channel impact Optimized Roaming to avoid sticky client

42 Wired-Wireless Integration for HD WiFi

43 One Network: Wireless Deployment Modes Autonomous FlexConnect Centralized Converged Access WAN Standalone APs Traffic Distributed at AP Traffic Centralized at Controller Traffic Distributed at Switch Target Positioning Purchase Decision Benefit Key considerations Small Wireless Network Branch Campus Branch and Campus Wireless only Wireless only Wireless only Wired and Wireless Simple and cost-effective Enterprise Class AP quality Provides Bridge functionality Limited features First step to Controller based Highly scalable for large number of branches No controller at branch L2 roaming only Branch with WAN bw and latency requirements Most feature rich solution Wireless Traffic visibility at the controller Top Performance and Scalability Wired & Wireless common operations One Enforcement Point One OS (IOS) Traffic visibility at every network layer Performance optimized for 11ac Access layer refresh (3650/3850)

44 Campus Design: Centralized, Controller-based Components Wireless LAN controllers Aironet Access Points Management (Prime Infrastructure) Mobility Service Engine (MSE) Principles Overlay Architecture Based on AireOS software AP must have CAPWAP connectivity with WLC Configuration downloaded to AP by WLC All Wi-Fi traffic is forwarded to the WLC MSE Campus Network Cisco Prime Infrastructure Wireless LAN Controller Aironet Access Point

45 Converged Access Deployment Overview Mobility Domain MO ISE PI Mobility Group MC MC Sub-Domain #1 Sub-Domain #2 SPG SPG MA MA MA MA MA MA

46 Working towards architectural integration Cisco ONE Architecture ISE, Prime, APIC Cisco Enterprise Aironet Catalyst ISR / ASA Cisco Cloud Managed MR MS MX Flexibility Simplicity

47 Cloud and on-premise deployment configurations Optimized for Ease of Management Hybrid Optimized for Flexibility and Control Cisco Enterprise Core / Datacenter Cisco Enterprise Campus & WAN Cisco Cloud Managed Cisco Cloud Managed Edge Cisco Cloud Managed Branch Cisco Enterprise Mid-Market Business Enterprise and Mid-Market Business

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49 Backup Slides

50 Below or Above Ceiling? AP Inside Ceiling Mount WAP Lot of interferences AP s RRM tends to reduce Tx power as it see AP LoS When Signal went through ceiling tile, Signal level is lowered from attenuation Automatic RF Power Control (TPC) can give less power then required Higher Co-Channel Interference between AP-to-AP Reduced Speed, Lowered Location accuracy WAP Exposed Ceiling Mount RF Signal from AP s back panel is reduced from ceiling s attenuation. No impact on performance WAP WAP AP s RF coverage is as site surveyed. Coverage & performance is getting mostly close its intended one. No attenuation

51 Comparisons per AP s installed area Above Ceiling Performance Lower Higher Interference between APs Higher Below ceiling lower RF Signal Strength Reduced to 50% (3dB) Maintain RF coverage and strength as it s planned Custom enclosure and Locker Possible Possible Location Accuracy Lower High Maintenance Higher Lower Installation Cost Higher ( Possibly, separate bracket or enclosure) Lower (Mount kit is included w/ 0$)