These topics introduce the Xirrus Wi-Fi Array, including an overview of its key
features and benefits, and a detailed listing of the product’s physical,
environmental, technology and regulatory specifications.
“The Xirrus Family of Products” on page 2.
“About this User’s Guide” on page 4.
“Why Choose the Xirrus Wi-Fi Array?” on page 7.
“Wi-Fi Array Product Overview” on page 9.
“Key Features and Benefits” on page 16.
“Product Specifications—XN16, XN12, and XN8” on page 20.
“Product Specifications—XN4” on page 27.
“Product Specifications—XS16/XS-3900, XS12, and XS8/XS-3700” on
page 34.
“Product Specifications—XS4/XS-3500” on page 40.
Introduction1
The Xirrus Family of Products
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Figure 1. Xirrus Arrays
The Xirrus family of products includes the following:
Wi-Fi Array
The XS Series of Xirrus Wi-Fi Arrays (XS16 / XS12 / XS8 / XS4)
XS Arrays integrate multiple Integrated Access Points—radios with highgain directional antennas for increased range and coverage. The Array
also incorporates an onboard multi-gigabit switch, Wi-Fi controller, and
firewall into a single device, along with a dedicated Wi-Fi threat sensor
and an embedded spectrum analyzer. The Wi-Fi Array provides more
than enough bandwidth, security, and control to replace switched
Ethernet to the desktop as the primary network connection. The XS16 has
16 IAPs, the XS12 has 12 IAPs, the XS8 has 8 IAPs, and the XS4 has 4 IAPs.
The XN Series of Xirrus Wi-Fi Arrays (XN16 / XN12 / XN8 / XN4)
The newest Xirrus Wi-Fi Arrays add the speed and reach of IEEE 802.11n
technology to the XS series of Arrays. The XN Series of Arrays feature the
capacity and performance needed to replace switched Ethernet to the
desktop. The XN16 has 16 IAPs, the XN12 has 12 IAPs, the XN8 has 8
IAPs, and the XN4 has 4 IAPs.
2Introduction
Wi-Fi Array
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Xirrus Management System (XMS)
XMS is used for managing large Array deployments from a centralized
Web-based interface. The XMS server is available pre-installed on the
Xirrus XM-33xx-CC Management Platform Series, or as a software
package (XA-3300-CC) to be installed on your own server hardware.
Figure 2 illustrates the elements of the Xirrus Management System. Users
start the XMS client simply by entering the URL of the XMS server on a
web browser. The XMS server manages a number of Wi-Fi Arrays via
SNMP.
Figure 2. The Xirrus Management System
If you need detailed information about this product, refer to the XMS
User’s Guide, part number 800-0007-001.
Xirrus Power over Gigabit Ethernet (PoGE)
The PoGE modules eliminate the need for running separate power
cabling. Additionally, an eight port module provides distributed power
to multiple Arrays, facilitating backup power when connected via a UPS.
Introduction3
Wi-Fi Array
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Nomenclature
Throughout this User’s Guide, the Xirrus Wi-Fi Array is also referred to as simply
the Array. In some instances, the terms product and unit are also used. When
discussing specific products from the Xirrus family, the product name is used (for
example, XN16, XS12, or XS-3500). The Wi-Fi Array’s operating system is referred
to as the ArrayOS. The Web Management Interface for browser-based
management of the Array is referred to as WMI.
The XS series of Arrays have two types of radios—the 5 GHz 802.11a radios are
named a1 to a12 (for 16-port models). The 802.11a/b/g radios are named abg1 to
abg4, and they support both 2.4GHz and 5 GHz. The XN series of Arrays also
have two types of radios—the 5 GHz 802.11a/n radios are named an1 through an12 (for 16-port models). The 802.11a/b/g/n radios are named abgn1 to abgn4,
and they also support both 2.4GHz and 5 GHz. When referring to a port that may
be on either an XN or XS model, the nomenclature abg(n) and a(n) will be used,
e.g., abg(n)2 or a(n)6.
The Xirrus Management System is referred to as XMS. The Power over Gigabit
Ethernet system may be referred to as PoGE.
About this User’s Guide
This User’s Guide provides detailed information and procedures that will enable
wireless network administrators to install, configure and manage the Wi-Fi Array
so that end users can take full advantage of the product’s features and
functionality without technical assistance.
Organization
Topics and procedures are organized by function under the following chapter
headings:
Introduction
Provides a brief introduction to wireless technology, an overview of the
product, including its key features and benefits, and presents the product
specifications.
4Introduction
Wi-Fi Array
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Installing the Wi-Fi Array
Defines prerequisites for deploying and installing the Array and provides
instructions to help you plan and complete a successful installation.
The Web Management Interface
Offers an overview of the product’s embedded Web Management
Interface, including its content and structure. It emphasizes what you
need to do to ensure that any configuration changes you make are
applied, and provides a list of restricted characters. It also includes
instructions for logging in to the Array with your Web browser.
Viewing Status on the Wi-Fi Array
Describes the status and statistics displays available on the Array using
its embedded Web Management Interface.
Configuring the Wi-Fi Array
Contains procedures for configuring the Array using its embedded Web
Management Interface.
Using Tools on the Wi-Fi Array
Contains procedures for using utility tools provided in the Web
Management Interface. It includes procedures for upgrading the system
firmware, uploading and downloading configurations and other files,
using diagnostic tools, and resetting the Array to its factory defaults.
The Command Line Interface
Includes the commands and the command structure used by the Wi-Fi
Array’s Command Line Interface (CLI), and provides a procedure for
establishing a Telnet connection to the Array. This chapter also includes
some sample key configuration tasks using the CLI.
Appendix A: Servicing the Wi-Fi Array
Contains procedures for servicing the Array, including the removal and
reinstallation of major hardware components.
Appendix B: Quick Reference Guide
Contains the product’s factory default settings.
Introduction5
Wi-Fi Array
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Appendix C: Technical Support
Offers guidance to resolve technical issues, including general hints and
tips to enhance your product experience, and a procedure for isolating
problems within an Array-enabled wireless network. Also includes
Frequently Asked Questions (FAQs) and Xirrus contact information.
Appendix D: Implementing PCI DSS
Discusses meeting security standards with the Array, including FIPS and
PCI DSS.
Appendix F: Notices
Contains the legal notices, licensing, and compliance statements for the
Array. Please read this section carefully.
Glossary of Terms
Provides an explanation of terms directly related to Xirrus product
technology, organized alphabetically.
Index
The index is a valuable information search tool. Use the index to locate
specific topics discussed in this User’s Guide. Simply click on any page
number in the index to jump to the referenced topic.
Notes and Cautions
The following symbols are used throughout this User’s Guide:
This symbol is used for general notes that provide useful supplemental
#
!
information.
This symbol is used for cautions. Cautions provide critical information that
may adversely affect the performance of the product.
Screen Images
Some screen images of the Web Management Interface have been modified for
clarity. For example, an image may have been cropped to highlight a specific area
of the screen, and/or sample data may be included in some fields.
Your User’s Guide as a PDF Document
6Introduction
Wi-Fi Array
This User’s Guide is also made available as a secure PDF (Portable Document
Format) file and can be viewed using the Adobe® Acrobat Reader® product. It
cannot be edited or modified. If you don’t have Acrobat Reader, you can
downloaded it free-of-charge from: http://www.adobe.com.
Hyperlinks
If you click on body text that appears in the color TEAL (with the exception of
headings or notes) the embedded hyperlink within the text will immediately take
you to the referenced destination. All internal and external cross-references,
including page numbers within the List of Figures and the Index, have associated
hyperlinks. After “jumping” to a referenced topic, if you want to return to the
previous page (reference source), simply click on Acrobat’s previous page button.
Window or Page?
Is a window a page, or is a page a window? There seems to be some dispute as to
what the correct term should be. For the sake of consistency, this document uses
the term Window when referring to how the Wi-Fi Array’s Web Management
Interface is displayed on your monitor.
Why Choose the Xirrus Wi-Fi Array?
The deployment of wireless LANs is becoming increasingly common as
businesses strive for greater flexibility in the workplace and the need for
employee mobility rises. The only requirements for an effective wireless
deployment are a power source, a couple of screws, and a little imagination.
Wireless LAN is also fully compatible with standard Ethernet protocols, so
connectivity with existing wired infrastructures is transparent to users—they can
still access and use the same applications and network services that they use
when plugged into the company’s wired LAN infrastructure (it’s only the plug
that no longer exists).
Wireless LAN has come a long way in the past few years and now offers the
performance, reliability and security that Enterprise customers have come to
expect from their networks. The technology is being driven by four major IEEE
standards:
Introduction7
Wi-Fi Array
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802.11a
Operates in the 5 GHz range with a maximum speed of 54 Mbps.
802.11b
Operates in the 2.4 GHz range with a maximum speed of 11 Mbps.
802.11g
Supports a higher transmission speed of 54 Mbps in the 2.4 GHz range
and is backwards compatible with 802.11b.
802.11n
Uses multiple antennas per radio to boost transmission speed as high as
300 Mbps, increasing throughput, range, and maximum number of users.
802.11n is backwards compatible with 802.11a/b/g.
Whether you have just a handful of users or thousands of users, wireless has the
scalability and flexibility to serve your needs.
See Also
Key Features and Benefits
Wi-Fi Array Product Overview
Product Specifications—XN16, XN12, and XN8
Product Specifications—XS4/XS-3500
Product Specifications—XS16/XS-3900, XS12, and XS8/XS-3700
The Xirrus Family of Products
8Introduction
Wi-Fi Array
Wi-Fi Array Product Overview
Part of the family of Xirrus products, the Wi-Fi Array is a high capacity, multimode device designed for the Enterprise market, with twice the range and up to
eight times the capacity of competitive wireless products.
Figure 3. Wi-Fi Array (XN16)
The Wi-Fi Array (regardless of the product model) is Wi-Fi® compliant and
simultaneously supports 802.11a, 802.11b and 802.11g clients. XN model arrays
add the enhanced abilities of 802.11n to this combination. Enterprise class features
such as VLAN support and multiple SSID capability enable robust network
compatibility and a high level of scalability and system control. The optional
Xirrus Management System (XMS) allows global management of hundreds of
Arrays from a central location.
Multiple versions of the Array with different numbers of Integrated Access Points
(IAPs) support a variety of deployment applications: 16 IAPs (XN16, XS16,
XS-3900), 12 IAPs (XN12, XS12), 8 IAPs (XN8, XS8, XS-3700), and 4 IAPs (XN4,
XS4, XS-3500).
Enterprise Class Security
The latest and most effective wireless encryption security standards, including
WPA (Wi-Fi Protected Access) and WPA2 with 802.11i AES (Advanced
Encryption Standard) are provided with the Wi-Fi Array. In addition, the use of
an embedded RADIUS server (or 802.1x with an external RADIUS server) ensures
user authentication—multiple Arrays can authenticate to the optional XMS,
ensuring only authorized Arrays become part of the wireless network. Rogue AP
Introduction9
Wi-Fi Array
detection, site monitoring, and RF spectrum analysis are performed in the
background by the Array automatically.
Wi-Fi Array Product Family
The following tables provide an overview of the main features supported by the
Wi-Fi Array product family.
XN Family of Arrays
FeatureXN16XN12XN8XN4
Number of
4444
802.11a/b/g/n radios
Number of
12840
802.11a/n radios
Tot al ra di os161284
Number of
48362412
integrated antennas
Integrated Wi-Fi switch ports161284
Integrated RF spectrum
YesYesYesYes
analyzer, threat sensors
Uplink Ports2221
Wi-Fi bandwidth4.8 Gbps3.6 Gbps2.4 Gbps1.2 Gbps
Users supported 1,024768512256
10Introduction
Wi-Fi Array
XS Family of Arrays
Feature
Number of
802.11a/b/g radios
Number of
802.11a radios
Tot al ra di os161284
Integrated Wi-Fi
switch ports
Integrated RF
spectrum analyzer
and threat sensors
Uplink Ports2221
Wi-Fi bandwidth864 Mb648 Mb432 Mb216 Mb
Users supported1,024768512256
XS16,
XS-3900
4444
12840
161284
YesYesYesYes
XS12
XS8,
XS-3700
XS4,
XS-3500
See Also
Key Features and Benefits
Wi-Fi Array Product Overview
Product Specifications—XN16, XN12, and XN8
Product Specifications—XS4/XS-3500
Product Specifications—XS16/XS-3900, XS12, and XS8/XS-3700
Power over Gigabit Ethernet (PoGE) (Optional)
Why Choose the Xirrus Wi-Fi Array?
Introduction11
Wi-Fi Array
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Deployment Flexibility
Xirrus’ unique multi-radio architecture generates 360 degrees of sectored highgain 802.11a/b/g/n or 802.11a/b/g coverage that provides extended range and
the highest possible data rates for a large volume of clients. Each sector can be
controlled automatically or manually, creating a pattern of wireless coverage
perfectly tailored to individual customer needs. For example:
outside wall
Figure 4. Wireless Coverage Patterns
Figure 4 depicts the following two scenarios:
Full pattern coverage
All radios are activated with coverage spanning 360 degrees. If within
range, clients will always receive coverage regardless of their geographic
position relative to the Array.
Partial pattern coverage
If desired, the Wi-Fi Array can be deployed close to an exterior wall. In
this case, half of all available radios have been deactivated to prevent
redundant signals from “bleeding” beyond the site’s perimeter wall. This
configuration may also be used in those cases where you want to restrict
wireless coverage to selected areas of the building’s interior.
See also, “Flexible Coverage Schemes” on page 18.
12Introduction
Wi-Fi Array
Power over Gigabit Ethernet (PoGE) (Optional)
The Xirrus XP1 and XP8 Power over Gigabit Ethernet modules provide power to
your Arrays over the same Cat 5e or Cat 6 cable used for data, eliminating the
need to run power cables and provide an AC power outlet in proximity to each
unit.
Figure 5. XP8 - Power over Ethernet Usage
Specific models of the Array are compatible with specific PoGE modules. For
details, please see “Power over Gigabit Ethernet Compatibility Matrix” on
page 414.
See Also
Key Features and Benefits
Wi-Fi Array Product Overview
Product Specifications—XN16, XN12, and XN8
Product Specifications—XS4/XS-3500
Product Specifications—XS16/XS-3900, XS12, and XS8/XS-3700
The Xirrus Family of Products
Why Choose the Xirrus Wi-Fi Array?
Introduction13
Wi-Fi Array
Enterprise Class Management
The Wi-Fi Array can be configured with its default RF settings, or the RF settings
can be customized using the Array’s embedded Web Management Interface
(WMI). The WMI enables easy configuration and control from a graphical
console, along with a full compliment of troubleshooting tools and statistics.
Figure 6. WMI: Array Status
In addition, a fully featured Command Line Interface (CLI) offers IT professionals
a familiar management and control environment. SNMP (Simple Network
14Introduction
Wi-Fi Array
Management Protocol) is also supported to allow management from an SNMP
compliant management tool, such as the optional Xirrus Management System.
For deployments of more than five Arrays, we recommend that you use the
#
See Also
Key Features and Benefits
Product Specifications—XN16, XN12, and XN8
Product Specifications—XN4
Product Specifications—XS4/XS-3500
Product Specifications—XS16/XS-3900, XS12, and XS8/XS-3700
Power over Gigabit Ethernet (PoGE) (Optional)
The Xirrus Family of Products
Why Choose the Xirrus Wi-Fi Array?
Xirrus Management System (XMS). The XMS offers a rich set of features
for fine control over large deployments.
Introduction15
Wi-Fi Array
an1
abgn1
an2
an3
an4
abgn2
an5
an6
an7
abgn3
an8
an9
an10
abgn4
an11
an12
Mode(s)IAP number
abgn2
(RF monitoring)
Key Features and Benefits
This section describes some of the key product features and the benefits you can
expect when deploying the Wi-Fi Array (the XN16 product is highlighted in this
section).
High Capacity and High Performance
The XN16 version of the Wi-Fi Array (Figure 7) easily handles time-sensitive
Figure 7. Layout of IAPs (XN16)
traffic such as voice, and can enable wireless connectivity for 1,024 users. The unit
includes two Gigabit uplink ports for connection to the wired network. A total of
sixteen IAPs provides a maximum wireless capacity of 4.8 Gbps, which offers
ample reserves for the high demands of current and future applications. Of the
sixteen IAPs, twelve operate as 802.11a/n radios (5 GHz band), and four operate
as 802.11a/b/g/n radios (5 GHz or 2.4 GHz bands), providing backwards
compatibility with 802.11b and 802.11g.
16Introduction
Wi-Fi Array
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a1
abg1
a2
a3
a4
abg2
a5
a6
a7
abg3
a8
a9
a10
abg4
a11
a12
Mode(s)IAP number
abg2
(RF monitoring)
In the recommended configuration, IAP (radio) abg(n)2 is configured in RF
monitoring and rogue AP detection mode.
Figure 8. Naming of IAPs (XS16)
Extended Coverage
One XN16 solution enables you to replace up to sixteen access points (includes
one omnidirectional IAP for monitoring the network). Fifteen IAP radios with
integrated directional antennas provide increased wireless range and enhanced
data rates in all directions. With a Wi-Fi Array deployed, far fewer access points
are needed and wired-like resiliency is delivered throughout your wireless
network. Your Wi-Fi Array deployment ensures:
Continuous connectivity if an IAP (radio) fails.
Introduction17
Continuous connectivity if an Array fails.
Continuous connectivity if a WDS link or switch fails.
Continuous connectivity if a Gigabit uplink or switch fails.
Wi-Fi Array
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802.11a/n
Monitor only
802.11a/b/g/n
Flexible Coverage Schemes
Your Wi-Fi Array offers flexible coverage schemes for each wireless technology.
Figure 9. Coverage Schemes
802.11a/n, 802.11a
Delivers 60° wireless coverage per IAP, with 6 dBi of gain.
802.11b/g/n, 802.11b/g
Delivers 180° wireless coverage, with 3 dBi of gain.
802.11a/b/g/n, 802.11a/b/g (monitor only)
Delivers 360° wireless coverage, with 2 dBi of gain.
Non-Overlapping Channels
Complete use of non-overlapping channels limits interference and delivers
maximum capacity. On the XN16, up to 16 non-overlapping channels are fully
utilized across the 5GHz and 2.4GHz spectrums (up to 12 across the 5GHz
spectrum plus up to 3 across the 2.4 GHz spectrum—typically, one additional
radio is used as a dedicated RF monitor).
Secure Wireless Access
Multiple layers of authentication and encryption ensure secure data
transmissions. The Wi-Fi Array is 802.11i compliant with encryption support for
40 bit and 128 bit WEP, WPA and WPA2 with TKIP and AES encryption.
Authentication support is provided via 802.1x, including PEAP, EAP-TLS, EAPTTLS, and LEAP (Lightweight Extensible Authentication Protocol) passthrough.
18Introduction
Wi-Fi Array
Applications Enablement
QoS (Quality of Service) functionality combined with true switch capabilities
enable high density video and Voice over Wireless LAN deployments. Compliant
with 802.1p and 802.1Q standards.
SDMA Optimization
SDMA (Spatial Division Multiple Access) technology provides full 360° coverage
while allowing independent channel and power output customization. Also
supports fast inter-zone handoffs for time-sensitive applications and roaming
support.
Fast Roaming
Utilizes the Xirrus Roaming Protocol (XRP) ensuring fast and seamless roaming
capabilities between IAPs or Arrays at both Layer 2 and Layer 3.
Easy Deployment
The Xirrus Management System (XMS) offers real time monitoring and
management capabilities of the wireless network—ideal for the Enterprise
market. It also allows you to import floor plans to help you plan your
deployment. The Xirrus Wi-Fi Array chassis has a plenum rated, lockable and
tamper resistant case.
See Also
Wi-Fi Array Product Overview
Product Specifications—XN16, XN12, and XN8
Product Specifications—XS4/XS-3500)
Product Specifications—XS16/XS-3900, XS12, and XS8/XS-3700
Power over Gigabit Ethernet (PoGE) (Optional)
The Xirrus Family of Products
Why Choose the Xirrus Wi-Fi Array?
Introduction19
Product Specifications—XN16, XN12, and XN8
ElementSpecifications
Number of UsersMaximum of 64 associated users per radio
XN16: 1024 users per Array
XN12: 768 users per Array
XN8: 512 users per Array
PhysicalDiameter: 18.65 inches (47.37 cm)
Height: 3.87 inches (9.83 cm)
Weight: 10 lbs (3.63 kg)
EnvironmentalOperating Temperature:
0°C to 55°C
0% to 90% relative humidity (non-condensing)
Wi-Fi Array
Storage Temperature:
-20°C to 60°C
5% to 95% relative humidity (non-condensing)
AC Input Power: 100-240VAC at 50-60 Hz
PoGE (DC) Input Power: Power over Gigabit
Ethernet—no splitter required, 48VDC,
Maximum 2A
Nominal Power:
XN16: 90W
XN12: 75W
XN8: 60W
All Models:
For PoGE, see “Power over Gigabit Ethernet
Compatibility Matrix” on page 414.
InterfacesSerial Console Port:
1 x RS232 – RJ45 connector, for local
configuration
Ethernet Interfaces:
2 x Gigabit 100/1000 Mbps uplink ports for link
aggregation, redundancy, or bridging
1 x Fast Ethernet 10/100 Mbps, for out of band
management
Status LEDs:
System status, Ethernet, Radio
NetworkingDHCP client, DHCP server (multiple DHCP
pools), DNS Client, NTP client, NAT
Introduction21
Wi-Fi Array
ElementSpecifications
ManagementXirrus Management System (XMS)—Layer 3
Element Management System
HTTPS Web Management Interface (WMI)
CLI via SSHv2, Telnet, local serial Console
Enable/disable management for any interface
Read-write and read-only admin accounts may
be authenticated via RADIUS
SNMP v2c, v3
Configuration Files—text-based files may be
imported, exported, or compared
NetFlow—IP flow information (traffic statistics
may be sent to an external Collector
FTP, TFTP
Syslog reporting for alerts/alarms—messages
may be stored on internal Syslog server or sent to
up to three external syslog servers.
Quality of Service
(QoS) Support
Cisco Discovery Protocol (CDP)—obtain protocol
addresses and platform information for
neighboring devices
Multiple SSIDs:
16 unique SSIDs per Array
Each SSID beacons a unique BSSID per radio
VLAN and QoS settings for each SSID
VLANs:
Up to 16 VLANs, 802.1Q, 802.1p
Prioritization:
802.11e wireless prioritization
802.1p wired prioritization
Fair queuing of downstream traffic
Wireless Voice Support:
Spectralink Voice Priority (SVP) protocol
22Introduction
Wi-Fi Array
ElementSpecifications
SecurityWireless Encryption
Line speed, hardware-accelerated encryption
modes:
WPA TKIP
WPA2 AES
WEP 40/64
WEP 104/128
Wireless Authentication:
Open
Pre-shared Key
802.1X EAP
PEAP
EAP-TLS
EAP-TTLS
EAP-LEAP Pass-through
Web Page Redirect (Captive Portal)
MAC Address Access Control List (ACL)
CHAP, PAP
1 Integrated Access Point can be set as a
dedicated Wi-Fi Threat Sensor
2 dBi 360° omni-directional antenna
802.11a/b/g/n External Antenna Connectors:
3 RP-TNC connectors (NOTE: TNC antenna
connection is not for outside plant connection.)
PerformanceClient Load Balancing
Automatic load balancing between system radios
Introduction25
Wi-Fi Array
ElementSpecifications
ComplianceElectromagnetic:
ICES-003 (Canada)
EN 301.893 (Europe)
EN 301.489-1 and -17 (Europe)
Safety:
EN 60950
EN 50371 to 50385
CE Mark
CertificationsWi-Fi Alliance: 802.11a/b/g, WPA, WPA2, and
extended EAP types. Our certifications may be
viewed here.
WarrantyHardware:
Five Year Standard (extendable)
Software:
90 Days Standard (extendable)
See Also
Key Features and Benefits
Wi-Fi Array Product Overview
Product Specifications—XN4
Product Specifications—XS16/XS-3900, XS12, and XS8/XS-3700
Product Specifications—XS4/XS-3500
Power over Gigabit Ethernet (PoGE) (Optional)
The Xirrus Family of Products
Why Choose the Xirrus Wi-Fi Array?
26Introduction
Wi-Fi Array
Product Specifications—XN4
ElementSpecifications
Number of UsersMaximum of 64 associated users per radio,
256 users per XN4
PhysicalDiameter: 12.58 inches (31.95 cm)
Height: 2.58 inches (6.55 cm)
Weight: 4lbs (1.81 kg)
EnvironmentalOperating Temperature:
0°C to 55°C
0% to 90% relative humidity (non-condensing)
Storage Temperature:
-20°C to 60°C
5% to 95% relative humidity (non-condensing)
ElectricalXN4 supports Power over Gigabit Ethernet
(PoGE) only, no splitter required
PoGE (DC) Input Power: 48VDC, Maximum 2A
Nominal Power: 35W
For PoGE, see “Power over Gigabit Ethernet
Compatibility Matrix” on page 414.
Introduction27
Wi-Fi Array
ElementSpecifications
InterfacesSerial Console Port:
1 x RS232 – RJ45 connector, for local
configuration
Ethernet Interfaces:
1 x Gigabit 100/1000 Mbps uplink port
Status LEDs:
System status, Ethernet, Radio
NetworkingDHCP client, DHCP server (multiple DHCP
pools), DNS Client, NTP client, NAT
ManagementXirrus Management System (XMS)—Layer 3
Element Management System
HTTPS Web Management Interface (WMI)
CLI via SSHv2, Telnet, local serial Console
Enable/disable management for any interface
Read-write and read-only admin accounts may
be authenticated via RADIUS
SNMP v2c, v3
Configuration Files—text-based files may be
imported, exported, or compared
NetFlow—IP flow information (traffic statistics
may be sent to an external Collector
FTP, TFTP
Syslog reporting for alerts/alarms—messages
may be stored on internal Syslog server or sent to
up to three external syslog servers.
Cisco Discovery Protocol (CDP)—obtain protocol
addresses and platform information for
neighboring devices
28Introduction
Wi-Fi Array
ElementSpecifications
Quality of Service
(QoS) Support
Multiple SSIDs:
16 unique SSIDs per Array
Each SSID beacons a unique BSSID per radio
VLAN and QoS settings for each SSID
VLANs:
Up to 16 VLANs, 802.1Q, 802.1p
Prioritization:
802.11e wireless prioritization
802.1p wired prioritization
Fair queuing of downstream traffic
Wireless Voice Support:
Spectralink Voice Priority (SVP) protocol
Introduction29
ElementSpecifications
SecurityWireless Encryption
Line speed, hardware-accelerated encryption
modes:
WPA TKIP
WPA2 AES
WEP 40/64
WEP 104/128
Wireless Authentication:
Open
Pre-shared Key
802.1X EAP
PEAP
EAP-TLS
Wi-Fi Array
EAP-TTLS
EAP-LEAP Pass-through
Web Page Redirect (Captive Portal)
MAC Address Access Control List (ACL)
CHAP, PAP
1 Integrated Access Point can be set as a
dedicated Wi-Fi Threat Sensor
2 dBi 360° omni-directional antenna
802.11a/b/g/n External Antenna Connectors:
1 RP-TNC connector (NOTE: TNC antenna
connection is not for outside plant connection.)
PerformanceClient Load Balancing
Automatic load balancing between system radios
32Introduction
Wi-Fi Array
ElementSpecifications
ComplianceElectromagnetic:
ICES-003 (Canada)
EN 301.893 (Europe)
EN 301.489-1 and -17 (Europe)
Safety:
EN 60950
EN 50371 to 50385
CE Mark
CertificationsWi-Fi Alliance: 802.11a/b/g, WPA, WPA2, and
extended EAP types. Our certifications may be
viewed here.
WarrantyHardware:
Five Year Standard (extendable)
Software:
90 Days Standard (extendable)
See Also
Key Features and Benefits
Wi-Fi Array Product Overview
Product Specifications—XN16, XN12, and XN8
Product Specifications—XS16/XS-3900, XS12, and XS8/XS-3700
Product Specifications—XS4/XS-3500
Power over Gigabit Ethernet (PoGE) (Optional)
The Xirrus Family of Products
Why Choose the Xirrus Wi-Fi Array?
Introduction33
Product Specifications—XS16/XS-3900, XS12, and
XS8/XS-3700
ElementSpecifications
Number of UsersMaximum of 64 associated users per radio
1024 users per Array (XS16/XS-3900)
768 users per Array (XS12)
512 users per Array (XS8/XS-3700)
PhysicalDiameter: 18.65 inches (47.37 cm)
Height: 3.87 inches (9.83 cm)
Weight: 8lbs (3.63 kg)
EnvironmentalOperating Temperature:
-10°C to 50°C
0% to 90% relative humidity (non-condensing)
Wi-Fi Array
Storage Temperature:
-20°C to 60°C
5% to 95% relative humidity (non-condensing)
SystemXS16/XS12/XS8:
1 GHz CPU
1 GB RAM
1 GB system flash
Expansion slot for future options
XS-3900/XS-3700:
825 MHz CPU
512 MB RAM (XS-3900/XS-3700)
512 MB system flash
Expansion slot for future options
34Introduction
Wi-Fi Array
ElementSpecifications
InterfacesSerial:
1 x RS232 – RJ45 connector
Ethernet Interfaces:
2 x Gigabit 100/1000 Mbps w/failover
1 x Fast Ethernet 10/100 Mbps
Status LEDs:
System status, Ethernet, Radio
ElectricalXS16/XS8:
Each Array supports both AC and PoGE
AC Input Power: 90-265VAC at 47-63Hz
PoGE Input Power: Power over Gigabit Ethernet—
no splitter required, 48VDC
Nominal Power:
XS16: 70W
XS8: 45W
XS-3900/XS-3700:
Separate AC and DC versions
Input Power (AC version): 90VAC to 265VAC at
47Hz to 63Hz
Input Power (DC version): 48VDC
PoGE: requires modified DC version and splitter.
monitoring)
3 x external RP-TNC connectors for three 802.11a/
b/g radios
Radio Approvals:
FCC (United States) and EN 301.893 (Europe)
*
*
* Note: External RP-TNC antenna connectors are
not for outside plant connection.
ManagementWeb-based HTTPS
SNMP v2c, v3
CLI via SSHv2 or Telnet
FTP
TFTP
Serial
Xirrus Management System (XMS)
Syslog reporting for alerts/alarms
38Introduction
Wi-Fi Array
ElementSpecifications
ComplianceUL / cUL 60950 and EN 60950
FCC Part 15.107 and 15109, Class A
EN 301.489 (Europe)
EN60601 EU medical equipment directive for EMC
CertificationsWi-Fi Alliance: 802.11a/b/g, WPA, WPA2, and
extended EAP types. Our certifications may be
viewed here.
Federal Information Processing Standard (FIPS)
Publication 140 -2, Level 2.
WarrantyOne year (hardware and software)
See Also
Key Features and Benefits
Wi-Fi Array Product Overview
Product Specifications—XN4
Product Specifications—XN16, XN12, and XN8
Product Specifications—XS4/XS-3500
Power over Gigabit Ethernet (PoGE) (Optional)
The Xirrus Family of Products
Why Choose the Xirrus Wi-Fi Array?
Introduction39
Product Specifications—XS4/XS-3500
ElementSpecifications
Number of UsersMaximum of 64 associated users per radio (256
users per Array)
PhysicalDiameter: 12.58 inches (31.95 cm)
Height: 2.58 inches (6.55 cm)
Weight: 4lbs (1.81 kg)
EnvironmentalOperating Temperature:
-10°C to 50°C
0% to 90% relative humidity (non-condensing)
Storage Temperature:
-20°C to 60°C
5% to 95% relative humidity (non-condensing)
Wi-Fi Array
System825 MHz CPU (XS4)
666 MHz CPU (XS-3500)
512 MB RAM, expandable (XS4)
256 MB RAM, expandable (XS-3500)
512 MB system flash, expandable
Expansion slot for future options
40Introduction
Wi-Fi Array
ElementSpecifications
ElectricalXS4:
Each Array supports both AC and PoGE
AC Input Power: 90-265VAC at 47-63Hz
Nominal power usage: 27W
XS-3500:
AC Input Power: 90-265VAC at 47-63Hz
Input Power (DC version): 48VDC
All Models:
Power over Gigabit Ethernet (PoGE): all 4-port
models work with all Xirrus PoGE modules,
splitter required, 48VDC
See “Power over Gigabit Ethernet Compatibility
Matrix” on page 414.
InterfacesSerial:
1 x RS232 – RJ45 connector
Ethernet Interfaces:
1 x Gigabit 100/1000 Mbps
Status LEDs:
System status, Ethernet, Radio
ManagementWeb-based HTTPS
SNMP v2c, v3
CLI via SSHv2 or Telnet
FTP
TFTP
Serial
Xirrus Management System (XMS)
Syslog reporting for alerts/alarms
4 x internal 3 dBi 180° 802.11b/g sectorized
1 x internal 2 dBi 360° omni-directional (for RF
monitoring)
1 x external RP-TNC connector for one 802.11a/b/
g radio (NOTE: TNC antenna connection is not for
outside plant connection.)
Radio Approvals:
FCC (United States) and EN 301.893 (Europe)
ComplianceUL / cUL 60950 and EN 60950
FCC Part 15.107 and 15109, Class A
EN 301.489 (Europe)
EN60601 EU medical equipment directive for EMC
Introduction43
ElementSpecifications
CertificationsWi-Fi Alliance: 802.11a/b/g, WPA, WPA2, and
extended EAP types. Our certifications may be
viewed here.
Federal Information Processing Standard (FIPS)
Publication 140 -2, Level 2.
WarrantyOne year (hardware and software)
See Also
Key Features and Benefits
Wi-Fi Array Product Overview
Product Specifications—XN16, XN12, and XN8
Product Specifications—XN4
Product Specifications—XS16/XS-3900, XS12, and XS8/XS-3700
Power over Gigabit Ethernet (PoGE) (Optional)
Wi-Fi Array
The Xirrus Family of Products
Why Choose the Xirrus Wi-Fi Array?
44Introduction
Wi-Fi Array
z
z
z
z
z
z
z
z
z
Installing the Wi-Fi Array
The instructions for completing a successful installation include the following
topics:
“Installation Prerequisites” on page 45.
“Planning Your Installation” on page 48.
“Installation Workflow” on page 80.
“Unpacking the Wi-Fi Array” on page 81.
“Installing Your Wi-Fi Array” on page 83.
“Powering Up the Wi-Fi Array” on page 107.
“Establishing Communication with the Array” on page 110.
“Performing the Express Setup Procedure” on page 112.
Installation Prerequisites
Your Wi-Fi Array deployment requires the presence of hardware and services in
the host wired/wireless network, including:
Power Source
Most Arrays are powered via Xirrus Power over Gigabit Ethernet. PoGE
supplies power over the same Cat 5e or Cat 6 cable used for data, thus
reducing cabling and installation effort. PoGE power injector modules are
available in 1 port and 8 port configurations and are typically placed near
your Gigabit Ethernet switch. An AC outlet is required for each injector
module. Current Array models have integrated splitters, so no separate
splitter is required.
Specific models of the Array are compatible with specific PoGE modules.
For details, please see “Power over Gigabit Ethernet Compatibility
Matrix” on page 414.
If your Arrays are equipped to accept AC power (and you are not using
PoGE), you need a dedicated power outlet to supply AC power to each
unit deployed at the site.
Installing the Wi-Fi Array45
Wi-Fi Array
z
z
z
z
Ethernet port
You need at least one 100/1000 BaseT port to establish wired Gigabit
Ethernet connectivity (via the product’s Gigabit 1 or Gigabit 2 port) and
one 10/100 BaseT port (if desired) for product management.
The Array’s Ethernet ports should be connected to an Ethernet switch, not
!
!
an Ethernet hub—if a hub is used, we recommend that you connect only
one Ethernet port.
The Gigabit1 Ethernet interface is the primary port for both data and
management traffic. If a single Ethernet connection is used, it must be
connected to the Gigabit1 Ethernet interface. See also, “Port Failover
Protection” on page 67.
The 10/100 Ethernet Port may be used for managing the Array out of
band from the Gigabit Ethernet ports. The 10/100 port will route only
management traffic, using a static route that may be configured for this
interface. See “interface” on page 336.
Secure Shell (SSH) utility
To establish secure remote command line access to the Array, you need a
Secure Shell (SSH) utility, such as PuTTY. The utility must be configured
to use SSH-2, since the Array will only allow SSH-2 connections.
Secure Web browser
Either Internet Explorer (version 6.0 or higher), Netscape Navigator
(version 7.0 or higher), or Mozilla Firefox (version 1.01 or higher).
A secure Web browser is required for Web-based management of the
Array. The browser must be on the same subnet as the Array, or you must
set a static route for management as described in the warning above.
Serial connection capability
To connect directly to the console port on the Array, your computer must
be equipped with a male 9-pin serial port and terminal emulation
software (for example, HyperTerminal). The Xirrus Array only supports
serial cable lengths up to 25’ per the RS-232 specification.
46Installing the Wi-Fi Array
Wi-Fi Array
z
z
Use the following settings when establishing a serial connection:
Bits per second115,200
Data bits8
ParityNone
Stop bits1
Flow controlNone
Optional Network Components
The following network components are optional.
Xirrus Management System (XMS)
The optional XMS offers powerful management features for small or large
Wi-Fi Array deployments.
External RADIUS server
Although your Array comes with an embedded RADIUS server, for
802.1x authentication in large deployments you may want to add an
external RADIUS server.
Client Requirements
The Wi-Fi Array should only be used with Wi-Fi certified client devices.
See Also
Coverage and Capacity Planning
Deployment Examples
Failover Planning
Planning Your Installation
Installing the Wi-Fi Array47
Wi-Fi Array
z
z
z
z
z
z
z
z
z
z
Planning Your Installation
This section provides guidelines and examples to help you plan your Xirrus Wi-Fi
Array deployment to achieve the best overall coverage and performance. We
recommend you conduct a site survey to determine the best location and settings
for each Array you install.
The following topics are discussed:
“General Deployment Considerations” on page 48
“Coverage and Capacity Planning” on page 50
“IEEE 802.11n Deployment Considerations” on page 59
“Failover Planning” on page 67
“Power Planning” on page 69
“Security Planning” on page 70
“Port Requirements” on page 72
“Network Management Planning” on page 75
“WDS Planning” on page 76
“Common Deployment Options” on page 79
For a complete discussion of implementing Voice over Wi-Fi on the Array,
#
see the Xirrus Voice over Wi-Fi Application Note in the Xirrus Library
.
General Deployment Considerations
The Wi-Fi Array’s unique multi-radio architecture generates 360 degrees of
sectored high-gain 802.11a/b/g/n or 802.11a/b/g coverage that provides
extended range. However, the number, thickness and location of walls, ceilings or
other objects that the wireless signals must pass through may affect the range.
Typical ranges vary depending on the types of materials and background RF
(radio frequency) noise at your location. To maximize wireless range, follow these
basic guidelines:
1.Keep the number of walls and ceilings between the Array and your
receiving devices to a minimum—each wall or ceiling can reduce the
48Installing the Wi-Fi Array
Wi-Fi Array
90°45°
1.5 feet/
.5 m
~ 3 feet/
1 m
> 42 feet\
14 m
2°
wireless range from between 3 and 90 feet (1 to 30 meters). Position your
devices so that the number of walls or ceilings is minimized.
2.Be aware of the direct line between each device. For example, a wall that
is 1.5 feet thick (half a meter) at 90° is actually almost 3 feet thick (or 1
meter) when viewed at a 45° angle. At an acute 2° degree angle the same
wall is over 42 feet (or 14 meters) thick! For best reception, try to ensure
that your wireless devices are positioned so that signals will travel
straight through a wall or ceiling.
3.Try to position wireless client devices so that the signal passes through
drywall (between studs) or open doorways and not other materials that
can adversely affect the wireless signal.
See Also
Coverage and Capacity Planning
Deployment Examples
Common Deployment Options
Installation Prerequisites
Figure 10. Wall Thickness Considerations
Installing the Wi-Fi Array49
Wi-Fi Array
100 ft/ 30m
100 ft/ 30 m
100 ft/
30 m
Coverage and Capacity Planning
This section considers coverage and capacity for your deployment(s), including
placement options, RF patterns and cell sizes, area calculations, roaming
considerations, and channel allocations.
Placement
Use the following guidelines when considering placement options:
1.The best placement option for the Array is ceiling-mounted within an
open plan environment (cubicles rather than fixed walls).
2.Keep the Array away from electrical devices or appliances that generate
RF noise. Because the Array is generally mounted on ceilings, be aware of
its position relative to lighting (especially fluorescent lighting)—we
recommend maintaining a distance of at least 3 to 6 feet (1 to 2 meters).
3.If using multiple Arrays in the same area, maintain a distance of at least
100 ft/30m between Arrays if there is direct line-of-sight between the
units, or at least 50 ft/15m if a wall or other barrier exists between the
units.
Figure 11. Unit Placement
50Installing the Wi-Fi Array
Wi-Fi Array
RF Patterns
The Wi-Fi Array allows you to control—automatically or manually—the pattern
of wireless coverage that best suits your deployment needs. You can choose to
operate with full coverage, half coverage, or custom coverage (by enabling or
disabling individual sectors).
Full (Normal) Coverage
In normal operation, the Array provides a full 360 degrees of coverage.
Figure 12. Full (Normal) Coverage
Half Coverage
If installing a unit close to an exterior wall, you can deactivate half of the radios to
prevent redundant signals from “bleeding” beyond the wall and extending
service into public areas. The same principle applies if you want to restrict service
to an adjacent room within the site.
outside wall
Figure 13. Adjusting RF Patterns
Installing the Wi-Fi Array51
Wi-Fi Array
Custom Coverage
Where there are highly reflective objects in proximity to the Array, you can turn
off specific radios to avoid interference and feedback.
reflective
object
Figure 14. Custom Coverage
Capacity and Cell Sizes
Cell sizes should be estimated based on the number of users, the applications
being used (for example, data/video/voice), and the number of Arrays available
at the location. The capacity of a cell is defined as the minimum data rate desired
for each sector multiplied by the total number of sectors being used.
Figure 15. Connection Rate vs. Distance
Figure 15 shows relative connection rates for 802.11n vs. 802.11a/g and 802.11b,
and the effect of distance on the connection rates. Wireless environments can vary
greatly so the actual rates may be different depending on the specific network
deployment.
52Installing the Wi-Fi Array
Wi-Fi Array
Large
Medium
Small
#
Fine Tuning Cell Sizes
Adjusting the transmit power allows you to fine tune cell sizes. There are four
standard sizes—Small, Medium, Large, or Max (the default is Max). There is also
an Auto setting that automatically determines the best cell size, and a Manual
setting that allows you to choose your power settings directly.
The XS4 and XN4 have a smaller range than the larger Arrays.
Figure 16. Transmit Power
Auto Cell Size is an automatic, self-tuning mechanism that balances cell size
between Arrays to guarantee coverage while limiting the RF energy that could
extend beyond the organizational boundary. Auto Cell uses communication
between Arrays to dynamically set radio power so that complete coverage is
provided to all areas, yet at the minimum power level required. This helps to
minimize potential interference with neighboring networks. Additionally, Arrays
running Auto Cell automatically detect and compensate for coverage gaps caused
by system interruptions. To enable the Auto Cell Size feature, go to “RF Power &
Sensitivity” on page 279. For a complete discussion of the Auto Cell size feature,
see the Xirrus Auto Cell Application Note in the Xirrus Library
Installing the Wi-Fi Array53
.
Wi-Fi Array
10 - 15% overlap
If you are installing many units in proximity to each other, we recommend that
you use Auto Cell Size; otherwise, reduce the transmit power using manual
settings to avoid excessive interference with other Arrays or installed APs. See
also, “Coverage and Capacity Planning” on page 50.
Sharp Cell
This patented Xirrus RF management option automatically creates more
intelligently defined cells and improves performance by creating smaller, highthroughput cells. By dynamically limiting each cell to a defined boundary (cell
size), the trailing edge bleed of RF energy is reduced, thus minimizing
interference between neighboring Wi-Fi Arrays or other Access Points. To enable
the Sharp Cell feature, go to “RF Power & Sensitivity” on page 279. For more
information about this feature, see the Xirrus Sharp Cell Application Note in the
Xirrus Library
.
Roaming Considerations
Cells should overlap approximately 10 - 15% to accommodate client roaming.
ROAMING
Figure 17. Overlapping Cells
Allocating Channels
Because the Wi-Fi Array is a multi-channel device, allocating the best channels to
radios is important if peak performance is to be maintained.
54Installing the Wi-Fi Array
Wi-Fi Array
z
z
z
Automatic Channel Selection
We recommend that you allow the Array to make intelligent channel allocation
decisions automatically. In the automatic mode, channels are allocated
dynamically, driven by changes in the environment. Auto Channel assignment is
performed by scanning the surrounding area for RF activity on all channels, then
automatically selecting and setting channels on the Array to the best channels
available. This function is typically executed when initially installing Arrays in a
new location and may optionally be configured to execute periodically to account
for changes in the RF environment over time. Auto Channel selection has
significant advantages, including:
Allows the Array to come up for the first time and not interfere with
existing equipment that may be already running, thereby limiting cochannel interference.
More accurately tunes the RF characteristics of a Wi-Fi installation than
manual configuration since the radios themselves are scanning the
environment from their physical location.
May be configured to run periodically.
To set up the automatic channel selection feature, go to “Advanced RF Settings”
on page 275. For more information about this feature, see the Xirrus Auto Channel
Application Note in the Xirrus Library
Manual Channel Selection
You can manually assign channels on a per radio basis, though manual selection
is not recommended (and not necessary).
To avoid co-channel interference, do not select adjacent channels for radios
The following examples employ 802.11a cells, each offering minimum
throughputs of 54 Mbps, 36 Mbps, and 18 Mbps per sector respectively, and
assume a floor plan covering a total area of about 60,000 square feet (5574 sq m).
Coverage and Capacity Planning
Failover Planning
Planning Your Installation
58Installing the Wi-Fi Array
Wi-Fi Array
z
z
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IEEE 802.11n Deployment Considerations
IEEE 802.11n features are supported only on XN Array models, and this
#
The Xirrus XN Arrays support IEEE 802.11n on all IAPs, in both 2.4 GHz and
5 GHz bands. Use of 802.11n offers significant benefits:
These benefits result in better support for a wide range of applications such as
voice and video, intensive usage such as CAD/CAM and backups, dense user
environments, and for manufacturing and warehousing environments.
section applies only to those Arrays.
Higher data rates
Higher throughput
Supports more users
More robust connections
Increased coverage area
More secure connections—supports WPA2 (Wi-Fi Protected Access 2)
While 802.11n increases coverage area by almost doubling the reach, you
#
The techniques that 802.11n uses to realize these performance improvements, and
the results that can be expected are discussed in:
Two very important techniques to consider are Channel Bonding and Multiple
Data Streams—Spatial Multiplexing because they contribute a large portion of
must consider the legacy wireless devices in your network. Wireless stations
connecting using 802.11a/b/g will still be subject to a reach of up to 100 feet,
depending on the environment.
“MIMO (Multiple-In Multiple-Out)” on page 60
“Multiple Data Streams—Spatial Multiplexing” on page 62
“Channel Bonding” on page 63
“Improved MAC Throughput” on page 64
“Short Guard Interval” on page 64
“Obtaining Higher Data Rates” on page 65
“802.11n Capacity” on page 66
Installing the Wi-Fi Array59
Wi-Fi Array
802.11n’s speed improvements and because they are optional and configurable, as
opposed to the parts of 802.11n that are fixed. While the settings for 802.11n IAPs
come pre-configured on the Array for robust performance in typical usage, you
should review the settings for your deployment, especially channel bonding. A
global setting is provided to enable or disable 802.11n mode. See “Global Settings
.11n” on page 273 to configure 802.11n operation.
MIMO (Multiple-In Multiple-Out)
MIMO (Multiple-In Multiple-Out) signal processing is one of the core
technologies of 802.11n. It mitigates interference and maintains broadband
performance even with weak signals.
Prior to 802.11n, a data stream was transmitted via one antenna. At the receiving
end, the antenna with the best signal was selected to receive data. (Figure 22)
Figure 22. Classic 802.11 Signal Transmission
60Installing the Wi-Fi Array
Wi-Fi Array
Frequency Across Subcarriers
Attenuation
Antenna 1 Signal
MIMO Processed Signal
Antenna 2 Signal
Antenna 3 Signal
Receiver
Figure 23. MIMO Signal Processing
MIMO signal processing uses multiple antennas to send and receive data. It takes
advantage of multipath reflections to improve signal coherence and greatly
increase receiver sensitivity (Figure 23). Multipath signals were considered to be
interference by 802.11a/b/g radios, and degraded performance. In 802.11n, these
signals are used to enhance performance. This extra sensitivity can be used for
greater range or higher data rates. The enhanced signal is the processed sum of
individual antennas. Signal processing eliminates nulls and fading that any one
antenna would see. MIMO signal processing is sophisticated enough to discern
multiple spatial streams (see Multiple Data Streams—Spatial Multiplexing). There
are no settings to configure for MIMO.
Installing the Wi-Fi Array61
Wi-Fi Array
%
Multiple Data Streams—Spatial Multiplexing
Spatial Multiplexing transmits completely separate data streams on different
antennas (in the same channel) that are recombined to produce new 802.11n data
rates. Higher data rates are achieved by splitting the original data stream into
separate data streams. Each separate stream is transmitted on a different antenna
(using its own RF chain). MIMO signal processing at the receiver can detect and
recover each stream. Streams are then recombined, yielding higher data rates.
Tx 1
Tx 2
Data StreamData Stream
Transmitter
%
Tx
N
Figure 24. Spatial Multiplexing
Rx 1
Rx 2
Rx
Receiver
M
Spatial multiplexing can double, triple, or quadruple the date rate, depending on
the number of transmit antennas used. The Array uses three chains for
transmitting and receiving.
62Installing the Wi-Fi Array
Wi-Fi Array
Ch#Ch#
40
20 MHz 20 MHz
36
40 MHz
(40, -1)
Standard 802.11 channels are
effectively 20MHz wide.
Channel bonding combines
two adjacent 20MHz channels
into a single 40MHz channel
providing increased throughput.
Channel Bonding
Channel bonding increases data rates by combining two adjacent 20 MHz
channels into one 40 MHz channel. This increases the data rate to slightly more
than double.
A bonded 40 MHz channel is specified in terms of the Primary channel and the
adjacent channel to Bond. The Bond channel is represented by +1 to use the
channel above the Primary channel, or -1 to use the channel below. In the example
shown, Channel 40 is the Primary channel and it is bonded to Channel 36, the
channel below it, by specifying -1. Be aware that Channel Bonding can make
channel planning more difficult, since you are using two channels for an IAP. We
recommend the use of the 5 GHz band, since it has many more channels than the
2.4 GHz band, and thus more channels are available for bonding.
The Array provides an Automatic Channel Bonding setting that will
automatically select the best channel for bonding on each IAP. If you enable this
option, you may select whether bonding will be dynamic (the bonded channel
changes in response to environmental conditions) or static (the bonded channel
will not be changed. See “Global Settings .11n” on page 273. To configure channel
bonding manually, on a per-IAP basis, see “IAP Settings” on page 255.
Figure 25. Channel Bonding
Installing the Wi-Fi Array63
Wi-Fi Array
z
z
z
Legacy Operation
High Throughput Operation
Data Frame
sss
ssssss
1
Data FrameBlock ACK Frame
1122NN
ACK Frame
12
ACK Frame
NN
Data Frame
SIFS
SIFS
SIFS
RIFSRIFS
Legacy Operation
High Throughput Operation
Data FrameACK Frame
sss
ssssss
1
12
Data FrameData FrameData Frame
Block ACK
Request
Frame
Block ACK
Response
Frame
12N
122
2
Data FrameACK Frame
N
ACK Frame
RIFS Usage (Reduced Inter-Frame Spacing)
Frame Aggregation
Improved MAC Throughput
These changes make 802.11n transmission of MAC frames 40% more efficient than
legacy transmission:
MAC data frames are combined and given a single PHY header.
Implicit Block ACK acknowledges all data frames within a combined
frame.
Spacing between frames is reduced.
Short Guard Interval
Data Frame
2
N
Figure 26. MAC Throughput Improvements
ACK Frame
PHY Header
MAC Header
Data Frame Payload
ACK Frame Payload
Data Frame
N
This option reduces the wait time between signals that are being sent out over the
air. The guard interval provides immunity to propagation delays and reflections,
and is normally 800 ns (long). By using a short guard interval (400 ns), the data
rate is increased by approximately 11%. The short interval may be used in many
environments (especially indoors). If the short guard interval is used in an
64Installing the Wi-Fi Array
Wi-Fi Array
z
z
z
z
inappropriate environment, the signal quality will suffer and throughput will
decrease. See “Global Settings .11n” on page 273 to configure the guard interval.
Obtaining Higher Data Rates
The data rate increase obtained by using 802.11n on an Array is incremental,
based on the technologies that are applied and the options that you select:
Higher encoding rates (Mandatory in 802.11n)
Spatial Streams (Mandatory, but multiplier varies directly with number of
streams selected.)
Channel Bonding (Mandatory in 802.11n, apply multiplier to IAP if it is
bonded.)
Short Guard Interval (Optional)
See Figure 27 to compute your 802.11n data rate increase for an IAP. Apply this
increase to the 802.11 a, b or g data rates selected for the Array.
Choose New Base
Encoding + Modulation
BPSK (6.5)
QPSK (13, 19.5)
QAM-16 (26, 39)
QAM-64 (58.5, 65)
xxx =
Optionally
Multiply by 2, 3, 4
for the Number of
Additional
Spatial Streams
Expected 802.11n Data Rates
802.11a 802.11g
Rates
6
9
12
18
24
36
48
54
11n Mandatory
Data Rates
6.5
13
19.5
26
39
52
58.5
65
One Spatial StreamTwo Spatial Streams
Figure 27. Computing 802.11n Data Rates
With Channel
Bonding (40MHz)
13.5
27
40.5
54
81
108
121.5
135
Optionally
Multiply By 2.077
to Bond
Two 20MHz
Channels
Expected First Generation Device Data Rates
With Short
Guard Interval
15
30
45
60
90
120
135
150
Optionally
Multiply by 1.11 for
Shorter Guard Interval
to Increase
Symbol Rate
Two Spatial
Streams
13
26
39
52
78
104
117
130
With Channel
Bonding (40MHz)
27
54
81
108
162
216
243
270
New 11n
Data Rate
With Short
Guard Interval
30
60
90
120
180
240
270
300
Installing the Wi-Fi Array65
Wi-Fi Array
802.11n Capacity
802.11n offers major increases in capacity over previous 802.11 standards, as
shown in Figure 28. Note that this chart shows figures for 802.11n (with one
spatial stream and channel bonding).
150
802.11a/n Capacity
802.11a/n Capacity
23 channels * 150Mbps = 3.4Gbps
23 channels * 150Mbps = 3.4Gbps
802.11a Capacity
802.11a Capacity
23 channels * 54Mbps = 1.2 Gbps
23 channels * 54Mbps = 1.2 Gbps
802.11g/n Capacity
802.11g/n Capacity
3 channels * 150Mbps = 450 Mbps
3 channels * 150Mbps = 450 Mbps
802.11g Capacity
802.11g Capacity
3 channels * 54Mbps = 162 Mbps
3 channels * 54Mbps = 162 Mbps
802.11b Capacity
802.11b Capacity
3 channels * 11Mbps = 33 Mbps
3 channels * 11Mbps = 33 Mbps
Figure 28. 802.11n Increases Capacity
66Installing the Wi-Fi Array
Wi-Fi Array
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Failover Planning
This section discusses failover protection at the unit and port levels.
Port Failover Protection
To ensure that service is continued in the event of a port failure, you can utilize
the Gigabit 1 and Gigabit 2 ports simultaneously.
Multiple port connections
Ethernet switch
Figure 29. Port Failover Protection
In addition, the Array has full failover protection between the Gigabit 1 and
Gigabit 2 Ethernet ports (see following table).
Bridges
Management
Traffic?
Fails Over To:IP address
Interface
Bridges
Data?
Fast EthernetNoYesNoneDHCP or
static
Gigabit 1YesYesGigabit 2DHCP or
static
Gigabit 2YesYesGigabit 1Assumes the
IP address of
Gigabit 1
The Wi-Fi Array Gigabit Ethernet ports actually support a number of modes:
802.3ad Link Aggregation
Installing the Wi-Fi Array67
Wi-Fi Array
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z
z
z
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Load Balancing
Broadcast
Link Backup
Bridged
Mirrored
For more details on Gigabit port modes and their configuration, please see
“Network Interface Ports” on page 184.
Switch Failover Protection
To ensure that service is continued in the event of a switch failure, you can
connect Arrays to more than one Ethernet switch (not a hub).
Ethernet connections
Ethernet switch
Figure 30. Switch Failover Protection
#
See Also
Coverage and Capacity Planning
Deployment Examples
Installation Prerequisites
Network Management Planning
Planning Your Installation
Power Planning
Security Planning
68Installing the Wi-Fi Array
Gigabit Ethernet connections must be on the same subnet.
Backup switch
Wi-Fi Array
Power Planning
All XN Series Array models and XS16/12/8/4 Arrays support Power over
Gigabit Ethernet (PoGE) with an integrated splitter. AC power is also supported
on all XN Arrays and some versions of the XS8, XS12, and XS16.
This section discusses the AC and PoGE power options.
AC Power
The AC power option requires a direct connection between the Array and a
dedicated AC power outlet. The power cord is provided with the unit.
Power over Gigabit Ethernet
To deliver power to the Array, you may use the optional XP1 or XP8 Power over
Gigabit Ethernet (PoGE) modules. They provide power over Cat 5e or Cat 6 cables
to the Array without running power cables—see Figure 5 on page 13.
Specific models of the Array are compatible with specific PoGE modules. For
details, please see “Power over Gigabit Ethernet Compatibility Matrix” on
page 414.
When using Cat 5e or Cat 6 cable, power can be provided up to a distance of
This section offers some useful guidelines for defining your preferred encryption
and authentication method. For additional information, see “Understanding
Security” on page 210 and the Security section of “Frequently Asked Questions”
on page 398.
Wireless Encryption
Encryption ensures that no user can decipher another user’s data transmitted
over the airwaves. There are three encryption options available to you, including:
WEP-40bit or WEP-128bit
Because WEP is vulnerable to cracks, we recommend that you only use
this for legacy devices that cannot support a stronger encryption type.
Wi-Fi Protected Access (WPA)
This is much more secure than WEP and uses TKIP for encryption.
Wi-Fi Protected Access (WPA2) with AES
This is government-grade encryption—available on most new client
adapters—and uses the AES–CCM encryption mode (Advanced
Encryption Standard–Counter Mode).
Authentication
Authentication ensures users are who they say they are, and occurs when users
attempt to join the wireless network and periodically thereafter. The following
authentication methods are available with the Wi-Fi Array:
RADIUS 802.1x
802.1x uses a remote RADIUS server to authenticate large numbers of
clients, and can handle different authentication methods (EAP-TLS, EAPTTLS, EAP-PEAP, and EAP-LEAP Passthrough). Administrators may
also be authenticated via RADIUS when preferred, or to meet particular
security standards.
Xirrus Internal RADIUS server
Recommended for smaller numbers of users (about 100 or less). Supports
EAP-PEAP only
70Installing the Wi-Fi Array
Wi-Fi Array
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Pre-Shared Key
Uses a pass-phrase or key that is manually distributed to all authorized
users. The same passphrase is given to client devices and entered into
each Array.
MAC Access Control Lists (ACLs)
MAC access control lists provide a list of client adapter MAC addresses
that are allowed or denied access to the wireless network, and can be
used in addition to any of the above authentication methods. ACLs are
good for embedded devices, like printers and bar-code scanners (though
MAC addresses can be spoofed). The Wi-Fi Array supports 1,000 ACL
entries.
Meeting PCI DSS Standards
The Payment Card Industry (PCI) Data Security Standard (DSS) was developed
by major credit card companies. It lays out a set of requirements that must be met
in order to provide adequate security for sensitive data. The the Wi-Fi Array may
be configured to satisfy PCI DSS standards. For details, please see Appendix D:
Implementing PCI DSS.
Meeting FIPS Standards
The Federal Information Processing Standard (FIPS) Publication 140-2 establishes
a computer security standard used to accredit cryptographic modules. The
standard is a joint effort by the U.S. and Canadian governments. To implement
Level 2 security requirements of FIPS Level 2 on the Wi-Fi Array, see Appendix E:
Implementing FIPS Security.
See Also
Failover Planning
Network Management Planning
Power Planning
Installing the Wi-Fi Array71
Wi-Fi Array
L2 Switching
Infrastructure
SMTP Server*
Internal
Resources
External Network /
Internet
Ports:
9090, 9091
Ports:
161, 162, 443
SSID Trafc on
VLANs A, B, etc.
Management over
Native VLAN
Trafc from Arrays
VLAN B
Trafc from Arrays
VLAN A
Trunked 802.1q
VLAN Connection
Ports:
25
Port Requirements
A number of ports are used by various Array features and by the Xirrus
Management System (XMS). The Port Requirements table on page 73 lists ports
and the features that require them (XMS port requirements are included in the
table for your convenience). If you are using a feature, please make sure that the
ports that it requires are not blocked by firewalls or other policies, and that they
do not conflict with any other port assignments.
As an example, XMS port requirements are illustrated in Figure 31. XMS requires
ports 161, 162, and 443 to be passed between Arrays and the XMS server.
Similarly, ports 9090 and 9091 are required for communication between the XMS
server and XMS clients, and port 25 is typically used by the XMS server to access
an SMTP server to send email notifications.
72Installing the Wi-Fi Array
* XMS Client and SMTP Server may be internal or external resources.
XMS Server
Figure 31. Port Requirements for XMS
XMS Client*
Firewall
Wi-Fi Array
The following table lists port requirements for the Array and for XMS, how they
are used, and whether they may be changed
Port Application PeerConfigurable
Array
20 tcp
21 udp
22 tcpSSHClientYes
23 tcpTelnetClientYes
25 tcp SMTP Mail ServerNo
69 tcpTFTP TFTP ServerNo
161 tcp/udpSNMPXMS ServerNo
SNMP Traphost Note -
162 tcp/udp
443 tcpHTTPS (WMI,WPR)ClientYes
Up to four Traphosts
may be configured.
FTPClientYes
.
XMS Server
Yes - bu t
required by
XMS
514 udpSyslogSyslog ServerNo
1812, 1645
udp
1813, 1646
udp
2055 udpNetflowClientYes
5000 tcpVirtual TunnelVTUN ServerYes
RADIUS (some
servers use 1645)
RADIUS Accounting
(some servers still use
1646)
RADIUS ServerYes
RADIUS Accounting
Server
Yes
Installing the Wi-Fi Array73
Wi-Fi Array
Port Application PeerConfigurable
XMS
25 tcp SMTPMail ServerYes
161 udpSNMPArraysNo
162 udpSNMP Traphost 1Arrays
443 tcp
514 udp
1099 tcpRMI Registry Internal*No
2000 tcpXMS Back-end Server Internal*No
3306 tcpMySQL Database Internal*No
8001 tcpStatus Viewer Internal*No
8007 tcpTomcat Shutdown Internal*
8009 tcpWeb ContainerInternal*
9090 tcpXMS WebserverXMS client
HTTPSArraysNo
Resident Syslog
server
Internal*
Via XMS
config file
Via XMS
config file
During
installation
During
installation
During
installation
9091 tcpXMS Client ServerXMS client
* Internal to XMS Server, no ports need to be unblocked on other network devices
Via XMS
config file
See Also
Management Control
External Radius
Services
VLAN Management
74Installing the Wi-Fi Array
Wi-Fi Array
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Network Management Planning
Network management can be performed using any of the following methods:
Command Line Interface, using an SSH (Secure Shell) utility, like PuTTY.
The utility must be set up to use SSH-2, since the Array will only allow
SSH-2 connections.
Web-based management, using the Array’s embedded Web Management
Interface (WMI). This method provides configuration and basic
monitoring tools, and is good for small deployments (one or two units).
Centralized Web-based management, using the optional Xirrus
Management System (XMS), which can be run on a dedicated Xirrus
appliance (XM-3300) or your own server. The XMS is used for managing
large Wi-Fi Array deployments from a centralized Web-based interface
and offers the following features:
Globally manage large numbers of Arrays (up to 500)
Seamless view of the entire wireless network
Easily configure large numbers of Arrays
Rogue AP monitoring
Easily manage system-wide firmware updates
Monitor performance and trends
Aggregation of alerts and alarms
See Also
Failover Planning
Power Planning
Security Planning
Installing the Wi-Fi Array75
Wi-Fi Array
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WDS Planning
WDS (Wireless Distribution System) creates wireless backhauls between arrays,
allowing your wireless network to be expanded using multiple Arrays without
the need for a wired backbone to link them (see Figure 32). WDS features include:
One to three IAPs may be used to form a single WDS link, yielding up to
900 Mbps bandwidth per link (up to 162 Mbps for XS model Arrays). Up
to three different WDS links may be created on a single Array.
Automatic IAP Load Balancing
If desired, you may allow clients to associate to a BSS on the same radio
interface used for a WDS Host Link. This will take bandwidth from the
WDS link.
Figure 32. WDS Link
Multiple links per Array allow you to configure multi-hop connections.
76Installing the Wi-Fi Array
Wi-Fi Array
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Multiple WDS links can provide link redundancy (failover capability - see
Figure 34). A network protocol (Spanning Tree Protocol—STP) prevents
Arrays from forming network loops.
Figure 33. A Multiple Hop WDS Connection
Figure 34. WDS Failover Protection
Installing the Wi-Fi Array77
Wi-Fi Array
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WDS links have a Host/Client relationship similar to the usual IAP/station
pattern for Arrays:
A WDS Client Link associates/authenticates to a host (target) Array in the
same way that a station associates to an IAP. The client side of the link
must be configured with the root MAC address of the target (host) Array.
A WDS Host Link acts like an IAP by allowing one WDS Client Link to
associate to it. An Array may have both client and host links.
WDS configuration is performed only on the client-side Array. See “WDS” on
page 285. Note that both Arrays must be configured with the same SSID name.
78Installing the Wi-Fi Array
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