The document discusses the importance of WLAN reliability for mission-critical applications and outlines five focus areas for achieving wire-like reliability, including downtime management, traffic optimization, and roaming efficiency. It emphasizes strategies such as controller virtualization, distributed switching, and dynamic management techniques to ensure a seamless user experience and avoid issues like data congestion and dropped sessions. The conclusion highlights that achieving these reliability goals is possible with careful planning, management, and integration of WLAN services.

1. Keys to Enterprise WLAN Reliability How to Achieve Wire-like Reliability Over the Air October 28, 2010

2. Today’s Speakers Mark Cowtan, Director Product Marketing, Trapeze Networks Matthew Herzog, Customer Support Manager, Trapeze Networks

3. WLAN Reliability Agenda Why WLAN reliability matters Five focus areas for reliability Downtime Traffic jams Disrupted roaming RF & Access limitations Competing services Conclusions, Q&A

4. WLAN Reliability – The Tipping Point Reliability Unwired Enterprise a\b\g\n b a/b/g Outdoor Access Mobility WIDS/WIPS Voice RTLS Telemetry Asset Management Multi Media Guest Access Security Management LAN Extension Performance Scalability Complete Coverage

5. Rapid Growth in Devices and Utilization Rapid Device Proliferation (SmartPhones and Other Clients) CAGR 90% CAGR 25% CAGR 44% Source: Gartner 04/2010 Spring Summer Break Fall 3x Growth in Sessions (Multiple Devices per Student) ~50,000 Students 3x Source: UoM 10/2010

6. What is WLAN Reliability to You? Wire-like Experience Always available Always connects Fast Ethernet rates End-User Expectations Predictable applications Landline quality voice Cable-quality video No restraints on mobility Supports my devices IT Manager Expectations Secure and assured sessions Easy management / provisioning Optimized resource utilization Scales easily and incrementally Low maintenance, no new staff

7. Is Wire-like Reliability Achievable? LAN Access Stationary user Dedicated bandwidth Fixed capacity WLAN Access Mobile user Shared bandwidth Variable capacity

8. Five Focus Areas for WLAN Reliability Downtime AP and controller resiliency Configuration and maintenance Traffic Jams Forwarding / encryption bottlenecks Disrupted Roaming Losing sessions or quality Crossing network boundaries RF & Access Limitations Wasted bandwidth or sessions Rogues, Interference, Old clients Competing Services Multimedia versus mission-critical

9. Configuring Controller Redundancy Hot Standby Approach Controller Virtualization Each controller has a unique configuration Each controller operates independently Back-up continuously polls front-line devices Many-to-one standby resiliency Back-up connects upon learning of failure All controllers get common configuration Cluster acts collectively as "virtual controller" Many-to-many in-service resiliency Dynamic AP load sharing across controllers Lowers maintenance: upgrades, changes Virtual Controller Cluster

10. How Controller Failover Works Hot Standby Approach Fully loaded hot standby required Catastrophic failure – all APs go down APs restart using hot standby controller Voice calls lost, data sessions stalled/lost Failover with no impact to session quality Even for active voice calls APs instantly remapped to in-service controller Dynamic AP load balancing across controllers No additional equipment required Virtual Controller Cluster Controller Virtualization

11. Immunity to Data Center Burnout Virtual Controller can span multiple Data Centers Boot from Group 1, Fail over to Group 2 Data Center 1 Data Center 2 Group 1 Group 2 Virtual Controller

12. Virtualization Can Eliminate Downtime APs have connections to primary and secondary controller APs load re-balanced when controller added or removed New AP additions evenly spread across cluster Allows in-service maintenance, at your convenience!

13. WLAN Reliability Agenda Why WLAN reliability matters Five focus areas for reliability Downtime Traffic jams Disrupted roaming RF & Access limitations Competing services Conclusions, Q&A

14. Where Do Different Functions Belong? Forwarding Packet classification Encryption Session keys Security profile Internet

15. Distributed Switching Scales for 802.11n All traffic flows through controller Traffic flows twice through network core 802.11n increases load up to 10x May require expensive upgrades Centralized Switching Reaches Capacity Sooner With Increased Load from 802.11n Distributed Switching Provides More Robust Handling of 802.11n Traffic Traffic can be forwarded by the AP Reduces burden on controller Optimizes traffic flows – ideal for voice Reduces 802.11n impact on controller 11n increases load by up to 10x Internet Internet

16. Distributed Cryptography Scales with APs Clear Encrytped Centralized Cryptography Distributed Cryptography Clear Mgmt Tunnel WPA2 etc

17. Distributed Improves Voice Reliability Longer path, more latency and jitter 3-6 times more latency Vulnerable to controller congestion Centralized Switching Distributed Switching Most direct path, optimal flows Lowest latency Toll-quality, no dropped calls

18. WLAN Reliability Agenda Why WLAN reliability matters Five focus areas for reliability Downtime Traffic jams Disrupted roaming RF & Access limitations Competing services Conclusions, Q&A

19. Ensuring Reliable Roaming Roaming within APs managed by same controller Everyone expects this and most vendors very reliable Part of IEEE 802.11i standard. Well defined mechanisms Roaming between controllers not a given No standards for cross-controller roaming Usually requires tunneling to home controllers Distributed session keys improve reliability One solution is fewer, bigger controllers Roaming across indoor / outdoor boundaries Some vendors don’t have common indoor / outdoor architecture Some vendors OEM outdoor solution Important evaluation criteria

20. Reliable Secure Roaming Expectations The way it should be…. Privileges and services follow users as they roam from AP to AP User credentials define access and network resource privileges Different groups with different privileges share infrastructure Privileges and services adjusted based on time, location, activity No network boundaries MOBILITY – SECURITY – SERVICES Centralized Policies Credentials & services follow user 2 AAA User roams 1

21. Standard Multi-Controller Roaming Client A on Subnet 1 Standard Roaming Client anchored to "home" controller for credentials and session info New controller unaware prior to connection, so must query network Long round trip through tunnel to original controller to maintain session High rate of timeout & dropped calls Increases load on controllers and doubles traffic on LAN core What about new .11k standard? Anchored Mobility for Basic Roaming Controller A Roam Client A on Subnet 1 Client B on Subnet 1 Subnet 1 Subnet 2 Controller B

22. Reliable Multi-Controller Roaming Client A on Subnet 1 Flexible Mobility for Reliable Roaming Reliable Roaming Credentials and session data spread across controllers Distributed session keys means mobile profile precedes roam Shorter data path Less risk of interruption Less risk of latency, overload Optimizes infrastructure flows No dependence on controller Local switching for further gains Optimized for toll-quality VoIP Controller A Controller B Subnet 1 Subnet 2 Client A on Subnet 1 Client B on Subnet 1 Mobility Domain A A Roam

23. WLAN Reliability Agenda Why WLAN reliability matters Five focus areas for reliability Downtime Traffic jams Disrupted roaming RF & Access limitations Competing services Conclusions, Q&A

24. Considerations for Reliable RF Access Radio transmission is a mysterious black art! Unlicensed spectrum, becoming crowded Legacy clients on a/b/g slow everyone else down What’s the right cell size? Do I need 2x2, 2x3, 3x3? What you can control up front: RF Coverage and Capacity design Managing and monitoring your WLAN What you can only respond to: Radio interference, Unwanted visitors, Malicious attacks

25. Keys to Reliable RF & Access Careful RF planning and layout of WLAN Main use of spectrum analysis, if desired Good management tools are essential Auto-Tuning and standard roaming features Automatic mitigation of AP down Wireless Intrusion Protection and Firewall Scanning for Rogue APs, entrants, and attacks “ Radio Firewall” around perimeter of building Load balancing / management techniques Band-steering, Client load balancing Call Admission Control for assured access Emerging methods for marginal enhancements Beamforming in sparse environments Spectrum Analysis to detect and avoid interference

26. Designing for Maximum Capacity Turn off low-data rates areas in outlying bands Turn down the power to reduce interference Smaller cells yield higher data rates for everyone Adjacent channel interference is easily avoided in 5 GHz band Reserve 2.4 GHz for legacy clients All clients enjoy high data rates

27. Tradeoff: Coverage or Capacity Coverage Capacity $/Mbps 100 Users 40 MHz Channels Identical area $/Sq. Ft. $/Mbps $/Sq. Ft. $/Mbps 3x Access points 2x Total cost 7x Avg throughput

28. Client Balancing Across APs and Bands 5 Ghz 1 2 2.4 Ghz Point of Entry Most clients default to 2.4Ghz on the AP with strongest signal

29. Differences in Call Admission Control Mobile phones connect to WLAN in idle, non-used state If your WLAN has Session CAC It counts sessions not active calls Is blind to non “voice” clients Drops roaming calls if at CAC limit Denies new calls if at CAC limit Session CAC Roam denied call dropped 2 active calls New caller session denied Any new client session denied limit 10 reached Dynamic CAC does not carry a false load Recognizes voice flows Only considers active calls Accepts roaming calls at CAC limit New caller call accepted Roam accepted 8 voice devices associated but idle Voice-grade service 8 voice devices associated but idle Dynamic CAC limit 10 not reached can accept more calls 2 active calls

30. WLAN Reliability Agenda Why WLAN reliability matters Five focus areas for reliability Downtime Traffic jams Disrupted roaming RF & Access limitations Competing services Conclusions, Q&A

31. Separate Management for Everything! Closed system, independent services, limited integration INTERNET COMMUNICATION SURVEILLANCE ASSET TRACKING

32. Poor User Experience Inconsistent service level for mission-critical applications Dropped sessions with peak loads Unaware of user context, location No proactive fault resolution High OpEx Unique UI for each service More devices to manage Cryptic disjointed information More complex, takes longer Need more skilled IT staff The Penalty of Services in Silos

33. Fully Integrated Services Enables SLAs WIDS/WIPS Server RF Firewall Location Appliance FCAPS Management WIDS/WIPS Server RF Firewall Location Appliance FCAPS & Services Management Typical WLAN Management Unified WLAN Management Guest Server Guest Server

34. WLAN Reliability Agenda Why WLAN reliability matters Five focus areas for reliability Downtime Traffic jams Disrupted roaming RF & Access limitations Competing services Conclusions, Q&A

35. Conclusion Reliability is needed for mission-critical applications Economics of mobility and “unwired enterprise” unstoppable End-to-end session reliability is a test-bed must do! Achieving Wire-like reliability IS possible! Controller virtualization eliminates downtime Distributed switching and crypto avoids traffic jams Distributed session keys improve roaming reliability RF Planning and load management assures access to medium Unified infrastructure & service management will allow SLAs Least mature aspect of whole solution for most vendors Drill down on vendor claims, and test them

36. Q & A Mark Cowtan, Director Product Marketing, Trapeze Networks Matthew Herzog, Customer Support Manager, Trapeze Networks