AirPlay and High-Density Wi-Fi at EDUCAUSE 2012 Overview For those not familiar, Educause is the premier information technology conference for higher education. The event draws attendees from all professional levels, sizes and types of both educational institutions and business allowing them to experience the latest trends in IT as applied to teaching and learning and its IT environment. Educause has a long history of providing reliable Internet access to its attendees. As many are responsible for their institution s IT infrastructure, the network remains a key resource for allowing them to remotely monitor and manage that infrastructure. Without convenient, highly available network access, their attendance would not be possible or highly disruptive at best. For these and the other attendees, Internet access is also the primary resource for communications within their institution and to colleagues around the world. Being able to communicate 24-x-7 regardless of location has become a staple of daily life for the IT professional and the myriad of other conference attendees. Over the years, Educause has strived to provide high quality Internet access to its attendees beginning with desktop terminals conveniently placed throughout the venue then migrating to wired Ethernet drops to support the emergence of laptops. Today, the laptop of a few years ago has given way to an explosion of personal mobile devices such as ipads, iphones and Android based mobile devices. Not only are these devices highly mobile, their only network access is totally wireless; no Ethernet port available! As such, a highly available, scalable and secure wireless infrastructure is required to service the more than 4,000 conference attendees without regard to their device choice, including the possibility that each attendee may sport more than one device. For Educause 2012, Aruba Networks was selected to provide the Wi-Fi infrastructure for the conference. The following pages are a synopsis of Aruba s experiences from developing the requirements to deploying and operating this large temporary infrastructure. Requirements To deliver the necessary performance, scale and availability, the following list of general requirements for the Wi-Fi infrastructure plus those specific to the 2012 venue at the Denver Convention Center was developed. BYOD Support There will be over 4,000 people attending this year s conference. Most attendees will bring a variety of devices and often use more than one concurrently (e.g. iphone and ipad or laptop). Therefore, the Wi-Fi infrastructure must accommodate access for a possible 6,000 concurrent devices. This includes connectivity for both the 2.4-GHz and 5-GHz bands as not all devices are capable of 5 GHZ. However, in this environment, 2.4 GHz will be considered an overlay with the primary service delivery at 5 GHz. Where possible, the network should direct or band-steer all capable devices to 5 GHz.
Performance and Scale The Wi-Fi infrastructure must accommodate all registered conference users assuming on average, two devices per user. To guarantee a favorable user experience, a minimum of 1 Mbps sustained and up to 3 Mbps burst per client must be available to accommodate video streaming, video conferencing and audio streaming plus transactional traffic such as email and web surfing. Authentication (Eduroam) User authentication will be provided by Educause via a RADIUS hierarchy for all conference attendees. This includes Eduroam which allows any Eduroam-enabled user to obtain network access at any institution connected to Eduroam. Depending on local policies at the visited institutions, Eduroam participants may also have additional resources (for example printers) at their disposal. Eduroam technology is based on 802.1X standard and a hierarchy of RADIUS proxy servers. The role of the RADIUS hierarchy is to forward the users credentials to the users home institution, where they can be verified and validated. The Wi-Fi infrastructure must be capable of 802.1X support allowing credentials to be passed to and from the RADIUS hierarchy. Address Management DHCP will be served by Educause. The Wi-Fi infrastructure must provide DHCP passthrough support. Administration and Operation The Wi-Fi infrastructure must include tools to monitor all network traffic with detailed statistics down to the user level. These tools will be used for operation and maintenance as well as provide information for future deployments. The requirements specific to Educause 2012 are as follows: Wells Fargo Theater The Wells Fargo Theater is a 500-seat, stadium-style venue that will be used for keynotes and a variety of group presentations. The Wi-Fi must be capable of delivering the specified per user performance to all seats. In addition, device association must not incur excessive (perceptible) delays. Address delivery and authentication provided by Educause must not be blocked or slowed by the Wi-Fi infrastructure allowing rapid connectivity after association. Session Rooms There are 68 session rooms of variable size supporting up to 100 seats. The Wi-Fi must be capable of delivering the specified per user performance to all seats. Session rooms adjacent to one another must not create perceptible interference to one another that would degrade network access or performance. Exhibit Hall Poster Area and Start-up Alleys Specific areas of the exhibit hall must be covered to support demonstrations in these areas as specified by the participants (not necessarily in advance). AirGroup While not a specific requirement, Aruba infrastructure supports a desirable self-service feature for Bonjour capable devices such as ipads. AirGroup allows these devices to discover local resources, such as printers, in or close to their geographic area enabling access with zero configuration. In addition, private groups can be setup to restrict access to local resources by the resource owner again without network administrator involvement (i.e. self-service). Given this advantage, AirGroup would be made available to help minimize the overhead of managing planned or ad-hoc local resource deployment. Deployment Schedule This year (as has been routine in the past), two days have been allotted in which to deploy and test the infrastructure. Deployment To deliver the required level of service, a total of 130 APs comprising a mix of Aruba AP-134s and AP-135s were deployed to provide wireless connectivity. These APs are capable of dual-band operation allowing concurrent access at 2.4 GHz and 5 GHz while accommodating up to 450 Mbps of traffic per AP. AP deployment was engineered with a maximum of 50 users per AP. AP placement was selected to insure the best opportunity for ARM to load balance users across the deployed APs. With a maximum of 50 users per AP consuming up to 3 Mbps each between two devices, the APs selected have more than enough capacity to handle the 150 Mbps maximum offered load. They are also capable of multi-stream MIMO. However, today s devices can only operate a single stream but this will be changing in the near future. ARM is used to effectively load balance traffic between APs in each venue as well as to autonomously assign the best orthogonal channels to minimize co-channel and adjacent channel interference enabling channel re-use where required. This was an extremely important feature given the density of APs required in the Wells Fargo Theater and the close proximity of session rooms to one another. Common Areas Common areas are provided for folks to gather for planned or spontaneous interaction as well as provide personal work/leisure space. The Wi-Fi must be capable of delivering the specified per user performance.
Looking more closely at the Wells Fargo Theater heat map, 32 APs were required to deliver connectivity to all 500 seats at the desired performance. However, given the small physical space into which these APs were deployed, additional care was necessary to insure reliable operation. This deployment required each AP to be strategically placed on the floor, in a protective enclosure under a seat to use the natural attenuation of the seats and the human bodies to advantage. Leveraging this natural attenuation enabled ARM to effectively select the best orthogonal channels and power levels between APs, enabling the channel reuse necessary to support the high number of APs deployed in close proximity to one another. It should be noted that the limited number of channels available at 2.4 GHz would never reliably support such high population densities in such a limited physical space. 5 GHz is the only practical primary service delivery for this type of venue. Where possible, all devices capable were band steered to 5 GHz. While not as severe as the Wells Fargo Theater, the session rooms were also in close proximity to one another as can be seen from the heat map above. This too required heavy reliance on ARM to minimize co-channel and adjacent channel interference as well as enabling channel re-use where required. While not perfect, 2.4-GHz performance was acceptable with minor incidents usually being resolved by the user relocating to an adjacent space if 5 GHz was not possible. APs were deployed on speaker stands with custom brackets matching the AP mounts. The APs were placed approximately six feet in the air at the locations shown on the map. This allowed fine tuning of the deployment with minimal overhead. Also, it s one of the most convenient ways to deploy APs in a temporary environment. All APs were powered using PoE again making the installation simple to setup. A total of 88 APs were deployed to covers these rooms and common areas. Common areas were deployed similarly to the session rooms except AP placement was easier to manage given the larger space available and distance from other venues.
Certain areas of the exhibit hall were covered by 10 APs to support demonstrations in the poster area and start-up alleys. As can be seen from the exhibit area heat map above, these areas were fairly well separated and presented very little problem in deployment and operation. However, there were some challenges from other vendor deployed Wi-Fi. On average, 45 rogue SSIDs were detected each day requiring some attention by ARM to insure conflicts were avoided. An Aruba 6000 Mobility Controller with M3 controller modules was selected for this deployment. Its primary functions were to terminate and manage APs, provide AirGroup support for convenient access to local resources and provide network administration, monitoring and reporting. For this deployment, authentication, IP address management and all intranet and internet routing was provided by the Educause Global Network. The controller provided the necessary support to pass along DHCP traffic as well as the 802.1X exchanges required for Eduroam authentication support. All AP traffic was tunneled to and from the AP and controller across the Educause network. ClearPass Policy Manager and ClearPass Guest were used for AirGroup self-service administration of AppleTV mirroring used for demos in the poster area and start-up alleys. Airwave was used for monitoring and statistic collection. Both services were setup on the management VLAN for communicating with the controller. The services provided were mapped across the following SSIDs: EducauseAir Wells Fargo Theater, session rooms, common areas Eduroam Wells Fargo Theater, session rooms, common areas PRG Session rooms, common areas E_Alley Exhibit floor poster area, start-up alleys The deployment took approximately two days and for the most part was fairly straight forward. Some accommodations were made in AP placement due to unavailability of Ethernet drops in certain areas. Also, session room attendance was unknown so the number and placement of APs in those rooms was an estimate. In the end, this proved to be a non-issue given the capacity of the APs selected and ARM s ability to manage frequency selection and power levels coupled with device load balancing. Network Usage Over the course of the conference, the network was heavily loaded as expected. There were over 3,000 users connected per day with traffic totals exceeding a 363 GB each day. The chart below demonstrates bandwidth consumption and trends over the course of the day:
It was evident that BYOD was in full force as the device types depicted on the right were numerous and varied. It s interesting to note the domination of ipads over laptops, empirically proving the paradigm has clearly shifted to tablets. Also note that individual user consumption is measured in GB as shown on the right, clearly demonstrating that multimedia dominates today s traffic. Observations and Conclusions Over the course of the conference s four days, the network delivered the required levels of performance and service with very little issue. With between 2,500 to 3,000 connections per day, peak bandwidths over 125 Mbps and individual client traffic exceeding 10 GB, the network remain highly available and stable. There were some minor issues each day with conflicts at 2.4 GHz. This was anticipated with the controller band-steering 2.4-GHz traffic to 5 GHz where possible. However, not all devices supported 2.4 GHZ and in high-density areas, they did experience degradation of performance or blocked connectivity. This was usually solved when the user relocated to a less populated area. Informal surveys were conducted with users in the session rooms as they exited the end of a session and with folks in the common areas. Much of the traffic usage cited was entertainment (movies and audio), email and web surfing.
All reported a satisfactory experience with the exception of a few 2.4-GHz users as previously mentioned. All were pleased that Eduroam support was provided and worked without incident. Also, those utilizing local print resources found the functionality of AirGroup very helpful in identifying the availability of printers close to their location. Those in the poster area and start-up alleys who used AirGroup self-service administration of AppleTV mirroring for demos were extremely pleased with its performance and the ease of use. Without the availability of AirGroup, many ad-hoc demonstrations would not have been possible do to the difficulty in coordinating with Educause staff for administering changes during the show. Many were excited that Aruba was pushing in front of an inevitable trend towards software defined networking (SDN) with self-service features like AirGroup. For more information on how to design and deploy high performance, highly available, Multimedia-grade Wi-Fi in temporary or permanent environments, refer to Aruba s validated reference designs at http://www.arubanetworks.com/vrd. www.arubanetworks.com 1344 Crossman Avenue. Sunnyvale, CA 94089 1-866-55-ARUBA Tel. +1 408.227.4500 Fax. +1 408.227.4550 info@arubanetworks.com 2012 Aruba Networks, Inc. Aruba Networks trademarks include AirWave, Aruba Networks, Aruba Wireless Networks, the registered Aruba the Mobile Edge Company logo, Aruba Mobility Management System, Mobile Edge Architecture, People Move. Networks Must Follow, RFProtect, and Green Island. All rights reserved. All other trademarks are the property of their respective owners. CS_Educause_113012