Leading K-12 School Districts around the globe are upgrading their existing Wi-Fi infrastructure and Ethernet workgroup switches with the Xirrus Wi-Fi Array because only the Wi-Fi Array is capable of delivering...

• Greater performance under heavy loads
• Greater user density in classrooms and lecture halls
• Greater coverage with fewer devices

As an example, a typical school building with two lecture halls and adjacent classrooms is covered with three Wi-Fi Arrays compared to 16 traditional access points. This 5:1 ratio saves in equipment costs, cabling costs, switch port costs, and labor costs.

Guide for Designing a Wi-Fi Network

Priority by Category

	Criteria	Requirements
Density	• Pervasive campus-wide high density • Support Computers on Wheels (CoW) • Eliminate need for dedicated computer labs • 50 - 200 concurrent associations per device • 25 - 100 concurrent students per device • Multiple Wi-Fi video projectors and cameras per device	• Multiple radios per device (4/8/16) • Ability to Utilize additional channels in 5GHz (802.11a/n) • Automatic user load balancing among radios
Performance	• Multiple Mbps real TCP/UDP throughput per user • Real-time applications – voice, video • Segmentation by students, staff, guests, devices, etc.	• Multiple radios per device (4/8/16) • Utilize 7X channel bandwidth in 5GHz (802.11a/n) • Local processing/switching/control at the AP • Gigabit Ethernet uplinks • QoS: WMM, 802.1p/Q • Fast and seamless Roaming
Coverage	• Multiple classrooms per device • Flexible control of coverage area	• High gain directional antennas • Automatic or manual control of coverage area • Ability to sharply define coverage boundaries for privacy
Security	• Rogue AP and threat detection • Authentication and encryption • Filtering/firewalling	• Integrated threat sensor • Proactive threat mitigation • RADIUS authentication with WPA2 encryption • Integrated rules-based stateful firewall • Station-to-station traffic blocking
Management	• Element management • RF management	• Common local and centralized management • Real-time RF coverage monitoring and control • Automatic channel selection • Location-based asset identification • Leverage existing management tools (syslog, SNMP, etc.)
Resiliency	• Hardware resiliency • Software resiliency • High availability	• Multiple radios with 50% coverage overlap • Dual Gigabit Ethernet uplinks • Dual software images with rollback • Configuration auditing and backup • Active service health check with self correction
Enclosures	• Flexible, secure installation options	• Securable, drop ceiling/surface mount indoor enclosures • Environmentally controlled outdoor enclosures
Power	• Flexible powering options	• AC and Power over Ethernet/Gigabit Ethernet options • Redundant power
Upgradeability	• Multi-generational hardware platform • Future proof for 802.11n	• Modular hardware and software for in-field upgrades • Hardware headroom for future requirements, performance boost • Design for 802.11n today – expandable to Cellular, Zigbee

Application Priority by Category

	Criteria	Requirements
Internet Applications	• Calculated Connections per Second (CPS) • Calculated Concurrent Connections (CC)	• Achieve desired CPS and CC • 100K average TCP throughput for web surfing and email • 500K average TCP throughput for file downloads
Video over Wi-Fi	• Measured # video streams at a given Media Deliver Index (MDI) or Video Quality Metric (VQM)	• High real-time throughput     º Internet streaming ~1 Mbps UDP per stream     º SDTV ~3 Mbps UDP per stream • Low packet loss • Seamless wireless-wired QoS • Low jitter
Voice over Wi-Fi	• Calculated Busy Hour Call Attempts (BHCA) • Calculated Busy Hour Call Completion (BHCC) at an acceptable Mean Opinion Score (MOS)	• Achieve desired BHCA/BHCC with MOS > 3.8 • Fast roaming – sub 60 msec handoff • Seamless wireless-wired QoS • Low latency and jitter

Services

	Criteria	Requirements
Planning	• Real world (non-predictive) site surveys	• Site surveys conducted with actual product • Test both signal (RSSI) and data throughput • Coverage guarantee
Installation	• Simplified installation	• "3" clicks or less to install a device • Automatic channel assignment at boot-up with zero interference • Quick physical install that can be done when school is in session
Verification	• Post-installation and verification	• Re-run site survey with throughput testing to verify design

Checklist for a Successful Wi-Fi Implementation

Most vendors offer a variety of products, some high-end with lots of features, some low-end for reduced costs and some require expensive software applications to enable features. When answering these questions verify the vendor is answering based on the proposed solution, not just available, costly upgrades.

Decision Criteria	Yes	No
Does Vendor support all standard LAN and WLAN standards without proprietary solutions or protocols that will limit the ability to expand the Wi-Fi network?
Can the vendor provide like type references?
Does the vendor provide site survey services? Is there a separate cost for this? Does the vendor perform the survey? Is the same equipment to be deployed used for the survey? Is it a live survey, vs. just predictive software? Do they perform a Spectrum Analysis to identify possible noise sources? Do they guarantee the results? Will they provide heatmaps of the coverage?
Is the platform(s), firmware and software upgradable to support future evolution of the 802.11 standard (i.e. 802.11n, 802.v, 802.11w...)?
Product Installation Will the vendor do the install? Is the installation free?
Support services Does the vendor directly support their products or via a 3rd party? Does the vendor offer free on site customer training on their product?
Security Certifications
Although not specifically education related, the following certifications give an indication of the level of security provided by the product. Are they supported?
PCI, HIPPA, FIPS-140
Coverage Is Access point able to support all 802.11a (extended channels)? Is access point able to simultaneously support 802.11 b/g/a radios? Does the Access point offer integrated high gain antennas for greater range?
Capacity Does the Access Point support multiple (4 or more) independent radios? Does the Access point offer a Sectored Antenna Architecture = Higher Data Rates at longer ranges?
Are the following Security Services supported? WEP, WPA & WPA2? Authentication: Open, MAC, 802.1x, WPR? Integrated Stateful Firewall in the AP? Integrated RADIUS server in the AP? Integrated IDS/IPS sensor?
Bandwidth and channel supported 802.11b? 802.11g? 802.11a? Is Proposed product Upgradable to 802.11n?
Power source, are the following supported Direct AC power? POE? POE over Gigabit connections? AC/DC redundancy?
High Availability Do proposed APs offer redundant uplink ports? Is Radio-to-Radio failover available?
Distributed design Is switching performed at the Access Point? Is QoS tagging applied at access point? Is Filtering/Firewall Policies applied at Access point?
Traffic encryption Is encryption/decryption performed at the Access Point? If encryption/decryption performed at controller how many APs can it support before being oversubscribed?
Is Wireless Distribution Services (WDS) available in the AP?
System Management Tools Does the proposed system offer Serial/CLI management? Does the proposed system offer Centralized SNMP management? Does the proposed system offer Web Based Management? Does the proposed system offer Management over the air? Does the proposed system offer Secure Management (SSH, HTTPS,)? Can management traffic be disabled on all interfaces?
RF Management Tools Does the proposed system offer an Integrated Spectrum Analyzer? Does the proposed system offer Auto Cell sizing? Does the proposed system offer Auto load balancing? Does the proposed system offer Auto channel selection?
Support for VoWi-Fi Is the proposed solution VIEW certified (Spectralink)?