Verwenden von Außenluft, um einen Serverraum zu kühlen Im Laufe der Jahre kam I8217ve zu erben und zu bewachen über mehrere Serverräume für verschiedene Unternehmen rund um den pazifischen Nordwesten. Die jüngste Hitzewelle hat mich denken viel über AC-System-Design bezieht sich auf Server-Räume. Wie typisch für kleine bis mittelständische Unternehmen, haben diese Server-Räume überall von 1 bis 4 Racks Getriebe pro Zimmer, und verwenden Sie Standard-Klimaanlage Bedingungstechniken, um diese Server cool zu halten. In einem gemäßigten Klima wie Seattle, wo die jährliche Durchschnittstemperatur 54 ° C liegt, scheint es sehr seltsam für mich, dass Server-Raum Kühlsysteme hier sind so wie sie sind in Südkalifornien (und dem Rest der Welt). Warum verschwenden all das Geld kämpfen 120F Wärme fließt aus dem Rücken der Server, wenn Sie konnte leicht entlüften, dass die Luft und haben eine frische Lieferung von schönen kalten Luft kommen von außen, ohne AC-Einheit in allen beteiligt Serverraumkühlung leicht verbraucht bis zu Die Hälfte Ihres Servers room8217s Gesamtenergieverbrauch und da you8217re ein heißes Schusssystem admin, warum nicht etwas intelligenter entwerfen (und sparen Sie etwas Bargeld, während you8217re an ihm) Traditionelles Klimatisierungssystem-Entwurf Traditionelles Fenster Wechselstromeinheit In den Häusern und in den Serverräumen, traditionell Die AC-Einheiten sind mit zwei getrennten Luftzonen konstruiert, die eine geschlossene Schleife innerhalb des Hauswirtschaftsraums bilden. Die Wechselstromeinheit nimmt Luft von außen auf, leitet sie durch die Kondensatorspulen, um Wärme zu sammeln, und entlüftet dann diese Heißluft nach außen. Auf der anderen Seite der Wechselstromeinheit wird Luft aus dem Inneren des Raumes eingeleitet, die von den Expansionsspulen (auch Verdampfer genannt) geleitet wird, die Wärme von der Luft absorbieren und diese kalte Luft wieder in den Kellerraum zurückführen. Dies ist typisch für fast alle AC units8230, ob es sich um einfache Fenstereinheiten oder komplexe Systeme handelt, die beiden Lufträume werden immer getrennt gehalten. Für Häuser, die AC nur erfordern, wenn es draußen heiß ist, ist dieses ein großes Design. Für Serverräume, die auch im Winter kühle Luft erfordern, fehlt dieser Standardauslegung der gesunde Menschenverstand. Traditionelles Split-Wechselstromgerät Das Standard-AC-Regelkreis-Design bedeutet, dass Sie einen neutralen Druck im Serverraum haben, so dass keine Luft ein - oder ausgefahren wird. Es bedeutet auch, dass Sie Ihre Wechselstromeinheit benutzen, um zu versuchen, die Gesamttemperatur im Bedienerraum zu verringern, also, wenn die heiße Luft, die die Bediener mit ihm vermischt, die resultierende Temperatur der Luft, die zurück in die Vorderseite der Bediener gesaugt wird, an oder ist Unter 80F. Für diejenigen von Ihnen in gemäßigten Klimazonen mit einer niedrigeren durchschnittlichen Temperatur, das heißt, Sie verwenden die 50F-60F Luft nach außen, um die Server-Raumtemperatur auf mindestens 70F zu senken, und zahlen hübsch dafür. Nachts wird es noch wütender, wenn die Temperaturen noch weiter sinken. Unterdessen hat jeder HVAC Installateur oder Auftragnehmer, mit dem Sie zuerst sprechen, keine Ahnung, was Sie sprechen, wenn Sie vorschlagen, mit externer Luft zu schlagen, und noch mehr viele verweigern, es zu installieren, sobald Sie ihnen Ihre Konzeptzeichnungen zeigen. WTF geht vor Warum sollte jedermann denken, dass ein Wechselstromsystementwurf für unterbrochenen Gebrauch in den Häusern bedeutete, nur wenn it8217s heiß draußen noch das beste Design ist, wenn es zu den Serverräumen kommt, die 8220always on8221 sind, egal was it8217s wie outside Here8217s ein klassisches Beispiel von ist Wie viele Serverräume konfiguriert sind. Diese Abbildung zeigt einen Multi-Rack-Serverraum, der ein standardisiertes Hochstock-Wechselstrom-System verwendet, aber das Konzept ist im Grunde dasselbe mit Overhead-belüfteten Wechselstromsystemen. Das erste Problem ist die geschlossene Schleife, wo die AC-Einheit kämpft die Heißluft, die von den Servern. Das zweite Problem ist die schlechte Luftstrom-Design im Server-Raum führt zu der ständigen Re-Zirkulation von heißen Server-Abgase werden von anderen Servern angesaugt. Das dritte Problem ist die Erhöhung der durchschnittlichen Racktemperatur, je weiter das Rack von der Wechselstromeinheit entfernt ist. Typisches System mit geschlossener Schleife Das größte Problem für die meisten Serverraum-Wechselstromsysteme ist das Mischen von Luft im Rechenzentrum. Das bedeutet, dass der Wechselstrom sehr kalte Luft (40F zu 50F) herausnehmen muss, also, wenn er mit der Umgebungsluft mischt, die ausgeglichene Temperatur irgendwo nah an mindestens 70F landet. Diese harte Arbeit in Anbetracht der Wechselstromeinheit nimmt normalerweise 90F bis 100F Luft, abhängig von Platzierung der Luftzufuhr und der Luftströmung innerhalb des Bedienerraumes. Mit Außenluft zu kühlen und schaffen positiven Druck Hier ist ein einfaches (schlecht gezeichnet) Design Ich peitschte in GIMP, die externe Luft verwendet. Wir ändern einfach die 8220homeroom8221 Seite Wechselstromeinheit Lufteinlass, um Luft von außen, nicht innerhalb des Serverraums zu akzeptieren. Dies schafft einen positiven Druck innerhalb des Serverraums und hält die AC-Einheit in Reihe, so dass, wenn die Luft nach draußen zu warm wird, wird der AC unit8217s eingebaut Thermostat Kick auf den Kompressor und starten Sie aktiv Kühlung der ankommenden Luft. Fügen Sie eine Entlüftung, um die heiße Luft von Ihren Servern nach außen ablassen und you8217ve haben eine externe Luftkühlung, die nur die AC unit8217s Kompressor, wenn die Luft nach draußen zu warm wird. Für den Seattle-Bereich, dass8217s ein Maximum von 3 Sommermonaten aus dem Jahr8230 und während dieser 3 Monate, würde der Wechselstrom wahrscheinlich nur während des Tages arbeiten müssen, da Nachttemperaturen normalerweise bequem unterhalb 60F fallen. Einfache Außenkonstruktion für gemäßigtes Klima Durch das Einziehen von Außenluft muss das Wechselstromgerät nur mit Außenlufttemperaturen, nicht mit heißen Abgastemperaturen, umgehen. Durch das Bewegen von Luft durch den Serverraum in einer einzigen Richtung und die Entlüftung der Heißluft direkt nach außen besteht nur eine geringe Wahrscheinlichkeit, dass sich der heiße Serverauspuff mit der kühleren Luft, die von außen eindringt, vermischt. Diese Luftströmung ist von wesentlicher Bedeutung, da sonst der heiße Serverschlauch sich mit der kühlen Außenluft vermischt und die Temperatur an der Server-Lünette erhöht. Nur durch die ordnungsgemäße Handhabung der Luftströmung können wir 70F Luft von außen verwenden, ohne dass ein Wechselstromaggregat-Kompressor auftritt. Der einzige Nachteil, den ich an diese einfache Designänderung denken kann, ist, dass es keine Möglichkeit gibt, die Luft, die in die Wechselstromeinheit kommt, vorzuwärmen, wenn die Temperatur außerhalb zu weit sinkt. I8217m ziemlich sicheres Ziehen -5F Luft in Ihre AC-Einheit würde wahrscheinlich einfrieren, und es ist definitiv nicht gut für Ihre Server. Wahrscheinlich wäre eine bessere Idee, dieses einfache Design mit Thermostaten und motorisierten Dämpfern zu erweitern. 8220T8221s. Und 8220Y8221s, um den Luftstrom zu steuern. Sie können automatisch einige der heißen Server-Abgase in die AC-Luftzufuhrleitung zurückführen, wenn die Temperatur außerhalb fällt. Dies würde Vorwärmen der Luft hereinkommen und speichern Sie Ihre AC-Einheit vor dem Einfrieren. Alternativ können Sie zwei separate Lufteinlässe haben. Die durch die AC-Einheit und eine, die kommt nur von außen. Wenn die Luft draußen wirklich kalt wird, könnte die Wechselstromeinheit so eingestellt werden, daß sie vollständig abschaltet, so daß keine Luft sich durch sie hindurch bewegt, und stattdessen können Dämpfer verwendet werden, um die Menge an kalter Luft, die von außen hereinkommt, zu steuern. Was ich hier zu bekommen ist, dass es eine Menge von einfachen Möglichkeiten, um die Nutzung von Außenluft. Es wird deutlich senken Sie Ihre Server-Raum Energie Rechnungen, helfen real Green Computing, und verringern die Auswirkungen auf die Umwelt. So kommen auf alle Sie smart Jungs und Gallonen, die Server-Räume da draußen, it8217s Zeit, um diese smarts nutzen und überdenken Ihre Server-Raum Kühlung. Obwohl die Wettergeschichte für Seattle (cityratingcityweather. aspcitySeattle) eine durchschnittliche relative Luftfeuchtigkeit von 88 für Oktober anzeigt, verwendet I8217ve RH-Sensoren sowohl innerhalb als auch außerhalb von vielen der Serverräume hier im Seattle-Gebiet und draußen schwebt immer um die 50-Marke . An einigen Tagen ist es8217s rund 40, andere it8217s um rund 60. Auf der anderen Seite sind die Betriebsdaten für meine HP DL360 G5 ProLiant-Boxen 10 8211 90. Feuchtigkeit ist ein Faktor für feuchte Klimata, aber für die Arten von temperaten Zonen I8217m sprechen Über, es shouldn8217t ein Anliegen sein. Im schlimmsten Fall könnte man einen Feuchtigkeitssensor verwenden, der mit einem Mikrocontroller oder einer anderen PLCmachine-Automatisierungslösung gekoppelt ist, um auf den AC oder auch nur einen Entfeuchter zu treten. Wir leben in FL und die Luftfeuchtigkeit ist schrecklich. Dieser Entwurf würde nicht zu gut für uns arbeiten, aber klingt wie es in einem coolerdryer Klima groß sein würde. Wir haben uns geothermische Klimaanlage, die 3-4 mal effizienter als die durchschnittliche HVAC-System und sie sind umweltfreundlich. Plus, können Sie eine 30 Steuergutschrift für sie auch erhalten Geothermische Konditionierer sind große Systeme. Die meisten der Zeit, it8217s die Installation Fragen rund um diese Arten von Systemen, die die meisten kleinen bis mittelständischen Unternehmen von immer Eigentum Eigentümer zu grünes Licht blockieren. Wenn Ihr Unternehmen besitzt ein eigenes Eigentum, dann sind dies die Art und Weise, in hotterhumid Klima gehen. I8217ve betrachtete auch eine spezielle Art des Hochleistungsverdampfungskühlsystems, das Coolerado (Coolerado) genannt wird. Es verwendet nur 600W pro 1 Tonne Modul, das erstaunlich8230 ist, aber es erfordert bis zu 4 Gallonen Wasser pro Stunde zu betreiben8230 und je feuchter die Umwelt, desto weniger effizient ist. I8217m tatsächlich die Arbeit an einem Projekt, die jetzt versuchen, realen Einsatz von Außenluft (oder was ich jetzt fordere 8220passive Kühlung8221) und andere Techniken wie thermische Masse und Boden sinken (wie passive geothermische). Erwarten Sie ein Update zu diesem Projekt in ein paar Monaten. Ich liebe die Idee. Du hast Recht. Warum würden Sie innen Luft verwenden, um irgendwo abkühlen, wenn it8217s 54 Grad draußen. Ich denke, you8217re großartig für den Versuch, die Effizienz von HVAC-Systemen, die für kleine Unternehmen genutzt werden können, verbessern. Cisco CleanAir - Cisco Unified Wireless Network Design Guide Spectrum Intelligence (SI) ist eine Kerntechnologie entwickelt, um proaktiv die Herausforderungen einer gemeinsamen geteilt Drahtloses Spektrum. Im Wesentlichen, SI bringt fortgeschrittene Interferenz-Identifizierung Algorithmen ähnlich denen, die in der militärischen verwendet, um die kommerzielle drahtlose Netzwerk-Welt. SI bietet Sichtbarkeit für alle Benutzer des gemeinsamen Spektrums, sowohl Wi-Fi-Geräte und fremde Störer. Für jedes Gerät, das im unlizenzierten Band arbeitet, sagt SI: Was ist es Wo ist es Wie beeinflusst es das Wi-Fi-Netzwerk Cisco hat den mutigen Schritt unternommen, SI direkt in die Wi-Fi-Silizium - und Infrastrukturlösung zu integrieren. Die integrierte Lösung, die so genannte Cisco CleanAir, bedeutet, dass der WLAN-IT-Manager zum ersten Mal nicht-802.11-Interferenzquellen identifizieren und lokalisieren kann, was die Bedienerfreundlichkeit und Sicherheit drahtloser Netzwerke erhöht. Am wichtigsten ist, dass ein integrierter SI die Bühne für eine neue Rasse von Radio Resource Management (RRM) setzt. Im Gegensatz zu früheren RRM-Lösungen, die nur andere WiFi-Geräte verstehen und anpassen können, eröffnet SI den Weg für eine RRM-Lösung der zweiten Generation, die alle Benutzer des drahtlosen Spektrums umfassend kennt und die Leistung im Gesicht optimieren kann Dieser vielfältigen Geräte. Der erste wichtige Punkt, der gemacht werden muss, ist, dass aus einer Design-Perspektive. CleanAir-aktivierte Access Points (APs) sind nur die APs und die Performance ist praktisch identisch mit den 1140-APs. Entwerfen für Wi-Fi-Abdeckung ist das gleiche mit beiden. CleanAir oder Interferenzidentifikationsverfahren sind ein passiver Prozess. CleanAir basiert auf dem Empfänger, und für die Klassifizierung zu funktionieren, muss die Quelle laut genug sein, um bei 10 dB über dem Rauschen Boden empfangen werden. Wenn Ihr Netzwerk so eingerichtet wird, dass Ihre Clients und APs einander hören können, kann CleanAir gut genug hören, um Sie auf Störungen in Ihrem Netzwerk aufmerksam zu machen. Die Deckungsanforderungen für CleanAir sind in diesem Dokument beschrieben. Es gibt einige spezielle Fälle, abhängig von der Implementierungsroute von CleanAir, die Sie letztendlich wählen. Die Technologie wurde entwickelt, um die derzeitigen Best Practices im Wi-Fi-Einsatz zu ergänzen. Dazu gehören die Bereitstellungsmodelle anderer weit verbreiteter Technologien wie Adaptive WIPS-, Voice - und Standorterweiterungen. Cisco empfiehlt, über CAPWAP und Cisco Unified Wireless Network (CUWN) zu verfügen. Die Informationen in diesem Dokument basieren auf diesen Software - und Hardwareversionen: CleanAir-fähige APs sind Aironet 3502e, 3501e, 3502i und 3501i Cisco WLAN Controller (WLC) mit der Version 7.0.98.0 Cisco Wireless Control System (WCS) mit der Version 7.0.164.0 Cisco Mobility Services Engine (MSE) mit Version 7.0 Weitere Informationen zu Dokumentkonventionen finden Sie unter Cisco Technical Tips-Konventionen. CleanAir ist ein System, kein Feature. CleanAir-Software und Hardwarekomponenten bieten die Möglichkeit, die Qualität des Wi-Fi-Kanals genau zu messen und die Nicht-WiFi-Quellen der Kanalinterferenz zu identifizieren. Dies kann nicht mit einem Standard-Wi-Fi-Chipsatz erfolgen. Um die Designziele und Anforderungen für eine erfolgreiche Implementierung zu verstehen, muss man verstehen, wie CleanAir auf einem hohen Niveau arbeitet. Für diejenigen, die bereits vertraut mit Ciscos Spectrum Expert-Technologie, ist CleanAir ein natürlicher evolutionärer Schritt. Aber es ist eine völlig neue Technologie, da es sich hierbei um eine unternehmensbezogene verteilte Spektrumanalyse handelt. Als solches ist es ähnlich wie Cisco Spectrum Expert in mancher Hinsicht, aber sehr unterschiedlich in anderen. Die Komponenten, Funktionen und Funktionen werden in diesem Dokument besprochen. Die neuen CleanAir-fähigen APs sind Aironet 3502e, 3501e, 3502i und 3501i. Die e bezeichnet eine externe Antenne, die I bezeichnet eine interne Antenne. Beide sind voll funktionsfähige 802.11n APs der nächsten Generation und laufen auf Standard 802.3af Macht. Abbildung 1: C3502E und C3502I CleanAir Capable APs Die Spectrum Analysis Hardware ist direkt in den Chipsatz des Funkgerätes integriert. Diese Zugabe fügte dem Funksilizium über 500 K-Logikgatter hinzu und hat eine außerordentlich enge Kopplung der Merkmale ermöglicht. Es gibt viele andere traditionelle Merkmale, die wurden hinzugefügt oder verbessert mit diesen Radios. Aber, es geht über den Rahmen dieses Dokuments und diese werden hier nicht behandelt. Es genügt zu sagen, dass auf der eigenen ohne CleanAir die 3500 Serie APs packen viele Features und Leistung zu einem attraktiven und robusten Enterprise-AP. Die grundlegende Cisco CleanAir-Architektur besteht aus Cisco CleanAir-fähigen APs und einem Cisco-WLAN-Controller (WLC). Cisco Wireless Control System (WCS) und Mobility Services Engine (MSE) sind optionale Systemkomponenten. Um den vollen Wert aus den Informationen zu ziehen, die das CleanAir-System liefert, sind WCS und MSE zusammen der Schlüssel zur Nutzung einer breiteren Wirksamkeit von CleanAir. Dies bietet Benutzerschnittstellen für erweiterte Spektrum-Funktionen wie historische Karten, Tracking-Interferenzgeräte, Standortdienste und Auswirkungen Analyse. Ein AP mit Cisco CleanAir-Technologie sammelt Informationen über Nicht-Wi-Fi-Interferenzquellen, verarbeitet diese und leitet sie an die WLC weiter. Das WLC ist ein integraler Bestandteil des CleanAir Systems. Die WLC steuert und konfiguriert CleanAir-fähige APs, sammelt und verarbeitet Spektraldaten und stellt sie dem WCS und dem MSE zur Verfügung. Das WLC stellt lokale Benutzeroberflächen (GUI und CLI) zur Verfügung, um grundlegende CleanAir-Funktionen und - Dienste zu konfigurieren und aktuelle Spektruminformationen anzuzeigen. Das Cisco WCS bietet erweiterte Benutzeroberflächen für CleanAir, die Funktionen zur Aktivierung und Konfiguration, konsolidierte Anzeigeinformationen, historische Luftqualitätsdatensätze und Berichtsmodule enthalten. Abbildung 2: Logischer Systemfluss Der Cisco MSE ist für die Lokalisierung und die historische Verfolgung von Interferenzgeräten und die Koordination und Konsolidierung von Interferenzberichten über mehrere WLCs erforderlich. Hinweis: Eine einzelne WLC kann nur Interferenzalarme für direkt angeschlossene APs konsolidieren. Die Koordination von Berichten, die von APs kommen, die an verschiedene Controller angeschlossen sind, erfordert die MSE, die eine systemweite Sicht auf alle CleanAir APs und WLCs hat. Herzstück des CleanAir-Systems ist die Spectrum Analysis Engine (SAgE) ASIC, der Spektrumanalysator auf einem Chip. Es ist jedoch weit mehr als ein Spektrumanalysator. Im Mittelpunkt steht ein leistungsstarker FFT-Motor mit 256 Punkten, der eine erstaunliche 78 KHz RBW (Resolution Band Width, die minimale Auflösung, die angezeigt werden kann) sowie die DSP Accelerated Vector Engine (DAvE). Die SAgE-Hardware läuft parallel zum Wi-Fi-Chipsatz und verarbeitet Informationen in der Nähe von Leitungsraten. All dies ermöglicht extreme Genauigkeit und Skalen für eine große Anzahl von wie Interferenzquellen, ohne Strafe im Durchsatz des Benutzerverkehrs. Der Wi-Fi-Chipsatz ist immer online. SAgE-Scans werden einmal pro Sekunde durchgeführt. Wenn eine Wi-Fi-Präambel erkannt wird, wird sie direkt zum Chipsatz weitergeleitet und wird nicht durch die parallele SAgE-Hardware beeinflusst. Während des SAgE-Scans gehen keine Pakete verloren, SAgE ist deaktiviert, während ein Wi-Fi-Paket durch den Empfänger verarbeitet wird. SAgE ist sehr schnell und genau. Auch in einer belebten Umgebung gibt es mehr als genug Scan-Zeit, um die Umwelt genau zu beurteilen. Warum ist RBW wichtig? Wenn Sie den Unterschied zwischen mehreren Bluetooth-Funkgeräten mit schmalen Signalen bei 1600 Hops pro Sekunde zählen und messen müssen, müssen Sie verschiedene Sender in Ihrer Probe trennen, wenn Sie wissen wollen, wie viele es gibt. Dies nimmt die Auflösung. Andernfalls würde es alle aussehen wie ein Puls. SAgE tut dies, und es tut dies gut. Wegen der DAvE und dem Bordgedächtnis assoziiert, gibt es die Möglichkeit, mehrere Probeninterferatoren parallel zu verarbeiten. Dies erhöht die Geschwindigkeit, mit der Sie den Datenstrom in nahezu Echtzeit verarbeiten können. In der Nähe von Echtzeit bedeutet, es gibt einige Verzögerung, aber es ist so minimal es braucht einen Computer zu messen. Cisco CleanAir APs erzeugen zwei grundlegende Informationen für das CleanAir-System. Für jede eingestufte Interferenzquelle wird ein IDR (Interference Device Report) erzeugt. AQIs (Air Quality Index) Berichte werden alle 15 Sekunden generiert und an Cisco IOS reg zur Mittelung und eventuellen Übertragung an den Controller auf der Basis des konfigurierten Intervalls weitergegeben. CleanAir Messaging wird in zwei neuen CAPWAP-Meldungsarten behandelt: Spectrum Configuration und Spectrum Data. Die Formate für diese Meldungen sind hier aufgeführt: Spektraldaten AP WLC Der Interference Device Report (IDR) ist ein detaillierter Bericht, der Informationen über ein eingestuftes Störungsgerät enthält. Dieser Bericht ähnelt sehr den Informationen, die in Cisco Spectrum Expert Active Devices oder Geräteansicht angezeigt werden. Aktive IDRs können auf der WLC-GUI und der CLI für alle CleanAir-Funkgeräte auf dem WLC betrachtet werden. IDRs werden nur an die MSE weitergeleitet. Dies ist das Format für einen IDR-Report: Tabelle 1 - Interferenzgerät-Report Hinweis: Interferenzquellen, die als Security Interferers markiert sind, sind benutzerdefiniert und können über Wireless konfiguriert werden. Gt 802.11abgn gt cleanair gt ermöglichen Interferenzen für Sicherheitsalarm. Jegliche Interferenzquelle, die klassifiziert wird, kann für eine Sicherheitsfallewarnung ausgewählt werden. Dies sendet einen Sicherheitsfalle an den WCS oder einen anderen konfigurierten Trap-Empfänger basierend auf dem gewählten Typ des Interferers. Diese Falle enthält nicht die gleichen Informationen wie eine IDR. Es ist einfach eine Möglichkeit, einen Alarm auf die Anwesenheit des Interferers auszulösen. Wenn ein Interferer als Sicherheitsmaßnahme bezeichnet wird, wird er als solcher im AP markiert und ist immer in den zehn Geräten enthalten, die vom AP gemeldet werden, unabhängig von der Schwere. IDR-Nachrichten werden in Echtzeit gesendet. Bei der Erkennung wird das IDR als Gerät markiert. Wenn es stoppt ein Gerät nach unten Nachricht gesendet wird. Eine Aktualisierungsnachricht wird alle 90 Sekunden vom AP für alle derzeit verfolgten Geräte gesendet. Dies ermöglicht Statusaktualisierungen von verfolgten Interferenzquellen und einen Audit-Trail, falls eine Aufwärts - oder Abwärtsnachricht beim Transit verloren gegangen ist. Luftqualität (AQ) Berichterstattung ist von jedem Spektrum fähig AP verfügbar. Air Quality ist ein neues Konzept mit CleanAir und stellt eine Gütemetrik des verfügbaren Spektrums dar und zeigt die Bandbreitenqualität für den Wi-Fi-Kanal an. Luftqualität ist ein rollender Durchschnitt, der die Auswirkungen aller klassifizierten Störungen auf ein theoretisch perfektes Spektrum auswertet. Die Skala ist 0-100, wobei 100 für Gut steht. AQ-Berichte werden unabhängig für jedes Radio gesendet. Der aktuelle AQ-Bericht ist auf der WLC-Oberfläche und der CLI sichtbar. AQ-Berichte werden auf dem WLC gespeichert und durch das WCS-Regelintervall abgefragt. Die Voreinstellung ist 15 Minuten (Minimum) und kann auf dem WCS auf 60 Minuten verlängert werden. Derzeit werten die meisten Standard-Wi-Fi-Chips das Spektrum aus, indem sie die gesamte Packetsenergie verfolgen, die beim Empfang demoduliert werden kann, und die gesamte Paketsenergie, die sie sendet. Jede Energie, die in dem Spektrum verbleibt, das nicht demoduliert oder durch RXTX-Aktivität erklärt werden kann, wird in eine Kategorie mit dem Namen Rauschen eingestürzt. In Wirklichkeit ist eine Menge des Rauschens tatsächlich Reste von Kollisionen oder Wi-Fi-Paketen, die unter die Empfangsschwelle für eine zuverlässige Demodulation fallen. Mit CleanAir wird ein anderer Ansatz verfolgt. Die gesamte Energie innerhalb des Spektrums, die definitiv NICHT Wi-Fi ist, wird klassifiziert und erklärt. Wir können auch sehen und verstehen Energie, die 802.11 moduliert und klassifiziert Energie, die von Co-Kanal und benachbarten Kanalquellen kommt. Für jedes klassifizierte Gerät wird ein Schweregrad berechnet (siehe Abschnitt "Schweregrad"), eine positive ganze Zahl zwischen 0 und 100, wobei 100 der stärkste ist. Der Interferenzschweregrad wird dann von der AQ-Skala subtrahiert (beginnend bei 100 gut), um den tatsächlichen AQ für ein Kanalradio, einen AP, einen Boden, ein Gebäude oder einen Campus zu erzeugen. AQ ist dann eine Messung der Auswirkungen aller klassifizierten Geräte auf die Umwelt. Es gibt zwei AQ-Reporting-Modi: normales und schnelles Update. Der Normalmodus ist der Standard-AQ-Berichtsmodus. Entweder das WCS oder das WLC ruft Berichte mit normaler Aktualisierungsrate ab (Standardeinstellung ist 15 Minuten). Das WCS informiert den Controller über den voreingestellten Polling-Zeitraum, und das WLC weist den AP an, die AQ-Mittelung und die Berichtsperiode entsprechend zu ändern. Wenn der Benutzer zum Überwachen der gt-Zugriffspunkte gt drückt und eine Funkschnittstelle aus dem WCS oder dem WLC auswählt, wird das ausgewählte Radio in den schnellen Aktualisierungs-Berichtsmodus versetzt. Wenn eine Anforderung empfangen wird, weist der Controller den AP an, die Standard-AQ-Berichtsperiode vorübergehend auf eine feste schnelle Aktualisierungsrate (30 Sek.) Zu ändern, was eine nahezu Echtzeit-Sichtbarkeit auf AQ-Änderungen auf Radioebene ermöglicht. Der Standard-Berichtsstatus ist EIN. Tabelle 3: Luftqualitätsbericht Hinweis: Im Zusammenhang mit der Frequenzberichterstattung stellt Air Quality Störungen von Nicht-Wi-Fi-Quellen und Wi-Fi-Quellen dar, die im Normalbetrieb von einem Wi-Fi-AP nicht erkannt werden (z. B. alter 802.11-Frequenztrichter) Geräte, veränderte 802.11-Geräte, benachbarte überlappende Kanalstörungen usw.). Informationen über WLAN-basierte Interferenzen werden vom AP mit dem Wi-Fi-Chip erfasst und gemeldet. Ein lokaler Modus-AP sammelt AQ-Informationen für den / die laufenden (n) Kanal (e). Ein Monitormodus-AP sammelt Informationen für alle unter Scanoptionen konfigurierten Kanäle. Die Standard-CUWN-Einstellungen für Land, DCA und Alle Kanäle werden unterstützt. Wenn ein AQ-Bericht empfangen wird, führt der Controller die erforderliche Verarbeitung durch und speichert ihn in der AQ-Datenbank. Wie bereits erwähnt, ist CleanAir die Integration der Cisco Spectrum Expert Technologie innerhalb eines Cisco AP. Während Ähnlichkeiten vorhanden sein könnten, ist dies ein frischer Gebrauch der Technologie und viele neue Konzepte werden in diesem Abschnitt dargestellt. Cisco Spectrum Expert stellte Technologie vor, die in der Lage war, nicht-Wi-Fi-Quellen von Radioenergie zu identifizieren. Dies ermöglichte es dem Bediener, sich auf Informationen wie Arbeitszyklus und Betriebskanäle zu konzentrieren und eine fundierte Entscheidung über das Gerät und seine Auswirkung auf ihr Wi-Fi-Netzwerk zu treffen. Spectrum Expert ermöglichte es dem Bediener, das gewählte Signal dann in das Gerätesuchgerät einzusperren und das Gerät physisch zu lokalisieren, indem es mit dem Instrument herumgeht. Das Entwicklungsziel von CleanAir besteht darin, mehrere Schritte weiter zu gehen, indem man den Bediener weitgehend aus der Gleichung entfernt und mehrere der Aufgaben innerhalb der Systemverwaltung automatisiert. Da Sie wissen, was das Gerät ist und was es beeinflusst, können bessere Entscheidungen auf Systemebene getroffen werden, was mit den Informationen zu tun ist. Mehrere neue Algorithmen wurden entwickelt, um Intelligenz, um die Arbeit, die mit Cisco Spectrum Experte gestartet wurde hinzuzufügen. Es gibt immer Fälle, die physische Deaktivierung einer Störung Gerät, oder eine Entscheidung über ein Gerät und Auswirkungen, die Menschen beinhaltet erfordert. Das Gesamtsystem sollte heilen, was geheilt werden kann und vermeiden, was vermieden werden kann, so daß die Anstrengung, das betroffene Spektrum zurückzugewinnen, eine proaktive Übung anstelle eines reaktiven sein kann. Lokaler Modus-AP (empfohlen) (LMAP) Ein Cisco CleanAir-AP, der im LMAP-Modus arbeitet, bedient Clients auf seinem zugewiesenen Kanal. Es überwacht auch das Spektrum auf diesem Kanal und diesen Kanal NUR. Dank der engen Silizium-Integration mit dem Wi-Fi-Radio kann die CleanAir-Hardware zwischen dem Verkehr auf dem aktuell zu bedienenden Kanal mit absolut keiner Strafe auf den Durchsatz der angeschlossenen Clients abhören. Das ist die Zeilenratenerkennung, ohne den Clientverkehr zu unterbrechen. Es gibt keine CleanAir-Wohnhäuser, die während normaler Off-Channel-Scans verarbeitet werden. Im Normalbetrieb führt ein CUWN Local Mode AP einen passiven Aus-Kanal-Scan der alternativen verfügbaren Kanäle in 2,4 GHz und 5 GHz durch. Off-Channel-Scans werden für die Systemwartung wie RRM-Metriken und Rogue-Detection verwendet. Die Häufigkeit dieser Abtastungen reicht nicht aus, um Rückwände zurückzuhalten, die für eine positive Geräteklassifikation erforderlich sind, so daß Informationen, die während dieser Abtastung geleert werden, durch das System unterdrückt werden. Eine Erhöhung der Häufigkeit von Off-Channel-Scans ist ebenfalls nicht erwünscht, da es von der Zeit abhängt, die der Funkverkehr verkehrt. Was bedeutet das alles Ein CleanAir AP im LMAP-Modus scannt nur einen Kanal jedes Bandes kontinuierlich. In normalen Unternehmensdichten sollte es viele APs auf demselben Kanal geben, und mindestens eine auf jedem Kanal, die davon ausgehen, daß RRM die Kanalauswahl verarbeitet. Eine Interferenzquelle, die schmalbandige Modulation verwendet (arbeitet auf oder um eine einzelne Frequenz) wird nur von APs erkannt, die diesen Frequenzraum teilen. Wenn die Interferenz eine Frequenzsprungart ist (verwendet mehrere Frequenzen, die allgemein das gesamte Band abdecken), wird sie von jedem AP erkannt, der es in dem Band hören kann. Abbildung 4: LMAP-AP-Erkennungsbeispiel In 2,4 GHz verfügen LMAPs über eine ausreichende Dichte, um in der Regel mindestens drei Punkte der Klassifizierung zu gewährleisten. Für die Standortauflösung sind mindestens drei Erkennungspunkte erforderlich. In 5 GHz gibt es 22 Kanäle, die in den Vereinigten Staaten arbeiten, so daß die Detektionsdichte und die ausreichende Ortsdichte weniger wahrscheinlich sind. Wenn jedoch auf einem von einem CleanAir AP belegten Kanal Störungen auftreten, erkennt er sie und warnt oder ergreift Maßnahmen, um zu verhindern, dass diese Funktionen aktiviert sind. Die meisten Interferenzen sind auf den Bereich von 5,8 GHz beschränkt. Dies ist, wo Verbraucher Geräte leben und daher, wo es am ehesten zu begegnen ist. Sie können Ihren Kanalplan einschränken, um mehr APs in dieses Feld zu zwingen, wenn Sie es wünschen. Allerdings ist es nicht wirklich gerechtfertigt. Denken Sie daran, Interferenz ist nur ein Problem, wenn es mit Spektrum Sie benötigen. Wenn Ihr AP nicht auf diesem Kanal ist, ist es wahrscheinlich, dass Sie noch viel Spektrum links zu bewegen. Wenn die Notwendigkeit, alle 5 GHz zu überwachen, von Sicherheitsrichtlinien gesteuert wird, sehen Sie unten die Definition des Monitormodus-AP. Monitor Mode AP (optional) (MMAP) Ein CleanAir Monitor Modus AP ist dediziert und dient nicht dem Clientverkehr. Es bietet Vollzeit-Scan aller Kanäle mit 40 MHz Wohnungen. CleanAir wird im Monitor-Modus zusammen mit allen anderen aktuellen Monitor-Modus Anwendungen einschließlich Adaptive WIPS und Standortoptimierung unterstützt. In einer Dual-Funk-Konfiguration sorgt dies dafür, dass alle Bandenkanäle routinemäßig gescannt werden. CleanAir-fähige MMAPs können als Teil einer umfassenden Implementierung von CleanAir-aktivierten LMAPs implementiert werden, um eine zusätzliche Abdeckung in 2,4 und 5 GHz oder als eigenständige Overlay-Lösung für die CleanAir-Funktionalität in einer vorhandenen Nicht-CleanAir-AP-Bereitstellung zur Verfügung zu stellen. In einem Szenario wie oben erwähnt, wo Sicherheit ein primärer Treiber ist, ist es wahrscheinlich, dass Adaptive WIPS wäre auch eine Voraussetzung. Dies wird gleichzeitig mit CleanAir auf demselben MMAP unterstützt. Es gibt einige verschiedene Unterschiede, wie einige der Features unterstützt werden, wenn die Bereitstellung als Overlay-Lösung. Dies wird in der Diskussion des Einsatzmodells in diesem Dokument behandelt. Spectrum Expert Connect-Modus SE Connect (optional) Ein SE Connect AP ist als dedizierter Spektrumsensor konfiguriert, der den Anschluss der Cisco Spectrum Expert-Anwendung auf einem lokalen Host ermöglicht, um den CleanAir AP als Remote-Spektrum-Sensor für die lokale Anwendung zu verwenden. Die Verbindung zwischen Spectrum Expert und dem Remote-AP umgeht den Controller auf der Datenebene. Der AP bleibt mit der Steuerung auf der Steuerebene in Berührung. Dieser Modus ermöglicht das Betrachten der Rohspektrumsdaten wie FFT-Diagramme und detaillierte Messungen. Alle CleanAir-Systemfunktionalität wird unterbrochen, während sich der AP in diesem Modus befindet und keine Clients bedient werden. Dieser Modus ist nur für die Remote-Fehlersuche gedacht. Die Spectrum Expert-Anwendung ist eine MS Windows-Anwendung, die eine Verbindung zu dem AP über eine TCP-Sitzung herstellt. Es kann in VMWare unterstützt werden. In CleanAir wurde das Konzept der Luftqualität eingeführt. Luftqualität ist ein Maß für den Prozentsatz der Zeit, in dem das Spektrum eines bestimmten beobachteten Containers (Radio, AP, Band, Stock, Gebäude) für den Wi-Fi-Verkehr verfügbar ist. AQ ist eine Funktion des Schweregrades, der für jede eingestufte Interferenzquelle berechnet wird. Der Severity-Index wertet jedes Nicht-Wi-Fi-Gerät über die Luftkennwerte aus und berechnet, wie viel Prozent der Zeit das Spektrum für Wi-Fi nicht verfügbar ist. Luftqualität ist ein Produkt der Schweregrade aller eingestuften Störquellen. Dies wird dann als Gesamtluftqualität durch Radiochannel-, Band - oder HF-Ausbreitungsdomäne (Boden, Gebäude) gemeldet und stellt die Gesamtkosten gegen die verfügbare Sendezeit aller Nicht-Wi-Fi-Quellen dar. Alles, was übrig ist, ist theoretisch für das Wi-Fi-Netzwerk für den Verkehr verfügbar. Dies ist theoretisch, weil es eine ganze Wissenschaft hinter der Messung der Effizienz der Wi-Fi-Verkehr, und das ist über den Rahmen dieses Dokuments. Jedoch zu wissen, dass Interferenz ist oder nicht Auswirkungen auf die Wissenschaft ist ein zentrales Ziel, wenn Ihr Plan ist der Erfolg bei der Identifizierung und Abschwächung der Schmerzen Punkte. Was macht eine Störquelle schwere Was bestimmt, ob es isor ist kein Problem Wie benutze ich diese Informationen, um mein Netzwerk zu verwalten Diese Fragen werden in diesem Dokument behandelt. In den einfachsten Worten, nicht-Wi-Fi-Nutzung kommt, wie oft ein anderes Radio ist mit meinem Netzwerk-Spektrum (Duty Cycle) und wie laut ist es in Bezug auf meine Radios (RSSIlocation). Die Energie in dem Kanal, der von einer 802.11-Schnittstelle gesehen wird, die versucht, auf den Kanal zuzugreifen, wird als Besetzt-Kanal wahrgenommen, wenn er über einer bestimmten Energieschwelle liegt. Dies wird durch eine klare Kanalbewertung (CCA) bestimmt. Wi-Fi verwendet eine vor dem Talk Kanal Zugriffsmethode für konkurrenzfreien PHY-Zugriff zu hören. Dies ist pro CSMA-CA (-CAcollisionsvermeidung). The RSSI of the interferer determines if it can be heard above the CCA threshold. The Duty Cycle is the on time of a transmitter. This determines how persistent an energy is in the channel. The higher the duty cycle the more often the channel is blocked. Simple severity can be demonstrated this way then using strictly the RSSI and the Duty Cycle. For illustration purposes, a device with 100 duty cycle is assumed. Figure 5: As interference signal decreases - AQI increases In the graph in this figure you can see that as the signal power of the interference decreases, the resulting AQI increases. Technically, as soon as the signal falls below -65 dBm, the AP no longer is blocked. You do need to think abut the impact this has on clients in the cell. 100 duty cycle (DC) ensures constant disruption of client signals with insufficient SNR in the presence of the noise. AQ rapidly increases once the signal power falls below -78 dBm. So far there are two of the three major impacts of interference defined in the severity based Air Quality metric: Interference is straightforward when looking at 100 DC. This is the type of signal most often used in demonstrations of the affect of interference. It is easy to see in a spectrogram, and it has a very dramatic affect on the Wi-Fi channel. This does happen in the real world too, for example in analog video cameras, motion detectors, telemetry equipment, TDM signals, and older cordless phones. There are a lot of signals that are not 100 DC. In fact, a lot of the interference that is encountered is interference of this type: variable to minimal. Here it gets a bit tougher to call the severity. Examples of interference of this type are Bluetooth, Cordless Phones, wireless speakers, telemetry devices, older 802.11fh gear and so on. For instance, a single Bluetooth headset does not do much damage in a Wi-Fi environment. However, three of these with overlapping propagation can disconnect a Wi-Fi phone if walked through. In addition to CCA, there are provisions in the 802.11 specifications such as the contention window, which is needed to accommodate airtime of different base protocols. Then you add to this various QOS mechanisms. All of these media reservations are used by different applications to maximize airtime efficiency and minimize collisions. This can be confusing. However, because all the interfaces on the air participate and agree on the same group of standards, it works very well. What occurs to this ordered chaos when you introduce a very specific energy that does not understand the contention mechanisms or for that matter does not even participate in CSMA-CA Well, mayhem actually, to a greater or lesser degree. It depends how busy the medium is when the interference is experienced. Figure 6: Similar but Different Channel Duty Cycles You can have two identical signals in terms of the Duty Cycle as measured in the channel and amplitude, but have two totally different levels of interference experienced on a Wi-Fi network. A fast repeating short pulse can be more devastating to Wi-Fi than a relatively slow repeating fat one. Look at an RF jammer, which effectively shuts down a Wi-Fi channel and registers very little duty cycle. In order to do a proper job evaluating, you need a better understanding of the minimum interference interval introduced. The minimum interference interval accounts for the fact that in-channel pulses interrupt Wi-Fi activity for some period longer than their actual duration, due to three effects: If already counting down, Wi-Fi devices must wait an additional DIFS period after the interference pulse. This case is typical for heavily loaded networks, where the interference starts before the Wi-Fis back-off counter has counted down to zero. If a new packet arrives to be transmitted mid-interference, the Wi-Fi device must additionally back off using a random value between zero and CWmin. This case is typical for lightly loaded networks, where the interference starts before the Wi-Fi packet arrives to the MAC for transmission. If the Wi-Fi device is already transmitting a packet when the interference burst arrives, the whole packet must be retransmitted with the next-higher value of CW, up to CWmax. This case is typical if the interference starts second, partially through an existing Wi-Fi packet. If the back off time expires without a successful retransmission, then the next back off is double the previous. This continues with unsuccessful transmission up to CWmax is reached or TTL is exceeded for the frame. Figure 7 - For 802.11bg CWmin 31, for 802.11a CWmin is 15, both have CWmax of 1023 In a real Wi-Fi network, it is difficult to estimate the mean duration of these three effects because they are functions of the number of devices in the BSS, overlapping BSSs, device activity, packet lengths, supported speeds protocols, QoS, and present activity. Therefore, the next best thing is to create a metric that remains constant as a reference point. This is what Severity does. It measures the impact of a single interferer against a theoretical network, and maintains a constant report of severity regardless of the underlying utilization of the network. This gives us a relative point to look at across network infrastructures. The answer to the question how much non - Wi-Fi interference is bad is subjective. In lightly loaded networks it is quite possible to have levels of non - Wi-Fi interference that go unnoticed by the users and administrators. This is what leads to trouble in the end. The nature of wireless networks is to become busier over time. Success leads to faster organizational adoption, and to new applications being committed. If there is interference present from day one, it is quite likely that the network have a problem with this when it becomes busy enough. When this happens it is difficult for people to believe that something that has been fine seemingly all along is the culprit. How do we use CleanAirs Air Quality and Severity metrics AQ is used to develop and monitor a baseline spectrum measurement and alert on changes indicating a performance impact. You can also use it for long term trend assessment through reporting. Severity is used to evaluate interference impact potential and prioritize individual devices for mitigation. Non Wi-Fi transmitters are less than friendly when it comes to unique characteristics that can be used to identify them. That is essentially what made the Cisco Spectrum Expert solution so revolutionary. Now with CleanAir there are multiple APs that potentially all hears the same interference at the same time. Correlating these reports to isolate unique instances is a challenge that had to be solved to provide advanced features, such as location of interference devices, as well as an accurate count. Enter the Pseudo MAC or PMAC. Because an analog video device does not have a MAC address or, in several cases, any other identifying digital tag an algorithm had to be created to identify unique devices being reported from multiple sources. A PMAC is calculated as part of the device classification and included in the interference device record (IDR). Each AP generates the PMAC independently, and while it is not identical for each report (at a minimum the measured RSSI of the device is likely different at each AP), it is similar. The function of comparing and evaluating PMACs is called merging. The PMAC is not exposed on customer interfaces. Only the results of merging are available in the form of a cluster ID. This merging is discussed next. Figure 8: Raw Detection of Interference In this graphic you can see several APs all reporting DECT, such as Phone energy. However, the APs in this graphic are actually reporting on the presence of two distinct DECT, such as Phone sources. Before the assignment of a PMAC and subsequent merging, there is only the device classification, which can be misleading. PMAC gives us a way to identify individual interference sources, even if they do not have any logical information that can be used such as an address. There are several APs all reporting a similar device. For each reporting AP, the PMAC is assigned to the classified signal. The next step is to combine the PMACs that are likely the same source device to a single report for the system. This is what merging does, consolidating multiple reports to a single event. Merging uses spatial proximity of the reporting APs. If there are six similar IDRs with five from APs on the same floor, and another one from a building a mile away, it is unlikely this is the same interferer. Once a proximity is established, a probability calculation is run to further match the distinct IDRs that belong and the result is assigned to a cluster. A cluster represents the record of that interference device and captures the individual APs that are reporting on it. Subsequent IDR reports or updates on the same device follow the same process and instead of creating a new cluster are matched to an existing one. In a cluster report, one AP is designated as the Cluster Center. This is the AP that hears the interference the loudest. Figure 9: After the PMAC Merge - APs hearing the same physical device are identified The merging algorithm runs on every CleanAir enabled WLC. A WLC performs the merge function for all IDRs from APs that are physically associated to it. All IDRs and resulting merged clusters are forwarded to an MSE, if it exists in the system. Systems with more than one WLC require an MSE to provide merging services. The MSE performs a more advanced merging function that seeks to merge clusters reported from different WLCs and extract location information to be reported to the WCS. Why do we need an MSE to merge IDRs across multiple WLCs Because a single WLC only knows the neighbors for the APs physically associated to it. RF Proximity cannot be determined for IDRs coming from APs located on different controllers unless you have a full system view. The MSE has this view. How physical proximity is determined differs, depending on how you implement CleanAir as well. For LMAP pervasive implementations, the APs all participate in Neighbor Discovery, so it is an easy matter to consult the RF neighbor list and determine spatial relationships for IDRs. In an MMAP overlay model you do not have this information. MMAPs are passive devices and do not transmit neighbor messages. Therefore, establishing the spatial relationship of one MMAP to another MMAP has to be done using X and Y coordinates from a system map. In order to do this, you also need the MSE that knows about the system map and can provide merging functions. More detail on the different modes of operation as well as practical deployment advice is covered in the deployment models section. Deploying APs in mixed mode LMAP CleanAir APs with an overlay of MMAP CleanAir APs is the best approach to high accuracy and total coverage. You can use the neighbor list created by the received neighbor messages for the MMAP as part of the merging information. In other words, if you have a PMAC from a LMAP AP and a PMAC from a MMAP, and the MMAP shows the LMAP AP as a neighbor, then the two can be merged with a high degree of confidence. This is not possible with CleanAir MMAPs deployed within legacy standard APs because those APs do not produce IDRs to compare with the merge process. The MSE and the X and Y references are still needed. Determining the location of a radio transmitter in theory is a fairly straightforward process. You sample the received signal from multiple locations and you triangulate based on the received signal strength. On a Wi-Fi network clients are located and Wi-Fi RFID tags with good results as long as there is a sufficient density of receivers and adequate signal to noise ratio. Wi-Fi clients and tags send probes on all supported channels regularly. This ensures that all APs within range hear the client or TAG regardless of the channel it is serving. This provides a lot of information to work with. We also know that the device (tag or client) subscribes to a specification that governs how it operates. Therefore, you can be certain that the device is using an omni-directional antenna and has a predictable initial transmit power. Wi-Fi devices also contain logical information that identifies it as a unique signal source (MAC address). Note: There is no guarantee of accuracy for location of non - Wi-Fi devices. Accuracy can be quite good and useful. However, there are a lot of variables in the world of consumer electronics and unintentional electrical interference. Any expectation of accuracy that is derived from current Client or Tag location accuracy models does not apply to non - Wi-Fi location and CleanAir features. Non Wi-Fi interference sources pose a special opportunity to get creative. For instance, what if the signal you are trying to locate is a narrow video signal (1 MHz) that is only affecting one channel In 2.4 GHz this probably works fine because most organizations have sufficient density to ensure that at least three APs on the same channel will hear it. However, in 5 GHz this is more difficult since most non-Wi-Fi devices only operate in the 5.8 GHz band. If RRM has DCA enabled with country channels, the number of APs actually assigned in 5.8 GHz declines because its goal is to spread out channel re-use and make use of open spectrum. This sounds bad, but remember if you are not detecting it, then it is not interfering with anything. Therefore, is really not a problem from a standpoint of interference. This is however an issue if your deployment concerns extend to security. In order to gain proper coverage you require some MMAP APs in addition to the LMAP APs to ensure full spectral coverage within the band. If your only concern is securing the operating space you are using, then you can also limit the channels available in DCA and force increased density in the channel ranges you wish to cover. The RF parameters of non - Wi-Fi devices can and do vary widely. An estimate has to be made based on the type of device that is being detected. The starting RSSI of the signal source needs to be known for good accuracy. You can estimate this based on experience, but if the device has a directional antenna the calculations will be off. If the device runs on battery power and experiences voltage sags or peaks as it operates, this will change how the system sees it. A different manufacturers implementation of a known product might not meet the expectations of the system. This will affect the calculations. Fortunately, Cisco has some experience in this area, and non-Wi-Fi device location actually works quite well. The point that needs to be made is that the accuracy of a non - Wi-Fi device location has a lot of variables to consider, accuracy increases with power, duty cycle, and number of channels hearing the device. This is good news because higher power, higher duty cycle, devices that impact multiple channels is generally what is considered to be severe as far as interference to the network goes. Cisco CleanAir APs, first and foremost, are access points. What this means is that there is nothing inherently different about deploying these APs over deploying any other currently shipping AP. What has changed is the introduction of CleanAir. This is a passive technology that does not impact the operation of the Wi-Fi network in any way, other than the noted mitigation strategies of ED-RRM and PDA. These are only available in a Greenfield installation and configured off by default. This section will deal with the sensitivity, density and the coverage requirements for good CleanAir functionality. These are not all that different from other established technology models such as a Voice, Video, or Location deployment. Valid deployment models for CleanAir products and feature functionality. Table 5: CleanAir Deployment Models vs Features CleanAir is a passive technology. All it does is hear things. Because an AP hears a lot farther than it can effectively talk this makes it a simple task to do a correct design in a Greenfield environment. Understanding how well CleanAir hears, and how classification and detection works, will give you the answers you need for any configuration of CleanAir. CleanAir depends on detection. The detection sensitivity is more generous than Wi-Fi throughput requirements with a requirement of 10 dB SNR for all classifiers, and many operable down to 5 dB. In most conceivable deployments where coverage is pervasive, there should not be any issues in hearing and detecting interference within the network infrastructure. How this breaks down is simple. In a network where the average AP power is at or between 5-11 dBm (power levels 3-5) then a class 3 (1 mW0 dBm) Bluetooth device should be detected down to -85 dBm. Raising the noise floor above this level creates a slight degradation in detection dB for dB. For design purposes it is worth adding a buffer zone by setting the minimum design goal to say -80. This will provide sufficient overlap in most conceivable situations. Note: Bluetooth is a good classifier to design for because it represents the bottom end power wise in devices you would be looking for. Anything lower generally does not even register on a Wi-Fi network. It is also handy (and readily available) to test with because it is a frequency hopper and will be seen by every AP, regardless of mode or channel in 2.4 GHz. It is important to understand your interference source. For instance Bluetooth. Here are multiple flavors of this in the market presently and the radios and specification have continued to evolve as most technologies do over time. A Bluetooth headset that you would use for your cell phone is most likely a class3 or class2 device. This operates on low power and makes ample use of adaptive power profiles, which extends battery life and reduces interference. A Bluetooth headset will transmit frequently on paging (Discovery mode) until associated. Then it will go dormant until needed in order to conserve power. CleanAir will only detect an active BT transmission. No RF, then nothing to detect. Therefore, if you are going to test with something, make sure it is transmitting. Play some music across it, but force it to transmit. Spectrum Expert Connect is a handy way to verify if something is, or is not transmitting and will end a lot of potential confusion. CleanAir was designed to compliment what is largely considered a normal density implementation. This definition of Normal continues to evolve. For instance, just five years ago 300 APs on the same system was considered a large implementation. In a lot of the world it still is. Numbers of 3,000-5,000 APs with many hundreds of them sharing direct knowledge through RF propagation are routinely seen. What is important to understand is: CleanAir LMAP supports the assigned channel only . Band Coverage is implemented by ensuring that channels are covered. The CleanAir AP can hear very well, and the active cell boundary is not the limit. For Location solutions, the RSSI cutoff value is -75 dBm. A minimum of three quality measurements is required for Location Resolution. In most deployments it is hard to image a coverage area that will not have at least three APs within ear shot on the same channel in 2.4 GHz. If there are not, then location resolution suffers. Add a Monitor Mode AP and use the guidelines. Remember that the location cutoff is -75 dBm corrects this because an MMAP listens to all channels. In locations where there is minimal density location resolution is likely not supported. But, you are protecting the active user channel extremely well. Also in such an area, you are generally not talking about a lot of space so locating an interference source does not pose the same problem as a multifloor dwelling. Deployment considerations come down to planning the network for desired capacity, and ensuring that you have the correct components and network paths in place to support CleanAir functions. RF proximity and the importance of RF Neighbor Relations cannot be understated. Make sure to understand PMAC and the merging process well. If a network does not have a good RF design, the neighbor relations is generally affected. This affects CleanAir performance. If you plan to install CleanAir MMAPs as an overlay to an existing network there are some limitations you need to keep in mind. CleanAir 7.0 software is supported on all of Ciscos shipping controllers. Each model controller supports the maximum rated AP capacity with CleanAir LMAPs. There are limits in the number of MMAPs that can be supported. The maximum number of MMAPs is a function of memory. The controller must store AQ details for each monitored channel. An LMAP requires two channels storage of AQ information. However, an MMAP is passively scanning and the channel data can be 25 channels per AP. Use the table below for design guidance. Always refer to the current release documentation for current information by release. Table 6: MMAP limits on WLCs Note: The numbers quoted for clusters (merged interference reports) and device records (individual IDR Reports before merging) are generous and highly unlikely to be exceeded in even the worst environments. Suppose you simply want to deploy CleanAir as a sensor network to monitor and be alerted about non - Wi-Fi interference. How many Monitor Mode APs (MMAPs) do you need The answer is generally 1-5 MMAP to LMAP radios. This of course depends on your coverage model. How much coverage do you get with an MMAP AP Quite a bit actually since you are strictly listening. The coverage area is far greater than if you also had to communicate and transmit. How about you visualize this on a map (you can use any planning tool available following a similar procedure as described below) If you have WCS and already have the system maps built, then this is an easy exercise. Use the planning mode in theWCS maps. Select Monitor gt Maps. Select the map you want to work with. In the right hand corner of the WCS screen use the radio button to select Planning Mode, then click go. Figure 10: WCS Planning mode Select the AP type. Use the default antennas for internal or change to match your deployment: 1 AP TX Power for both 5 GHz and 2.4 GHz is 1 dBm Class3 BT 1 mW Select ADD AP at the bottom. Figure 11: Add AP in WCS planner Move the AP to place on your map and select apply. The heat map populates. Choose -80 dBm for the RSSI cutoff at the top of the map, the map re-draws if this is a change. Here is what your CleanAir MMAP covers for 1 dBm out to -80 dBm. These results show a cell with a radius of 70 feet or 15,000 ft2 of coverage. Figure 12: Example Coverage of CleanAir MMAP using 1 dBm power and -80 dBm cutoff for coverage Note: Keep in mind that this is a predictive analysis. The accuracy of this analysis depends directly on the accuracy of the maps used to create it. It is beyond the scope of this document to provide a step by step instruction on how to edit maps within a WCS. A good question you want to ask is are these MMAPs going to be deployed strictly for CleanAir Or, are you going to take advantage of the many benefits that can be derived from the inclusion of monitoring APs in your network All of these applications work with CleanAir enabled APs. For Adaptive wIPS, refer to the Cisco Adaptive wIPS Deployment Guide as the coverage recommendation of Adaptive wIPS are similar, but dependent on your goals and customers needs. For location services ensure that you review and understand the deployment requirements for your technology. All of these solutions are complimentary with CleanAir design goals. Why should I not mix CleanAir LMAP and Legacy LMAP APs in the same physical area This question pertains to this use case: I currently have non CleanAir APs deployed (1130,1240, 1250, 1140) in local mode. I want to add just a few CleanAir APs to increase my coveragedensity. Why cant I just add some APs and get all the CleanAir features This is not recommended because CleanAir LMAPs only monitor the serving channel and all CleanAir features rely on measurement density for quality. This installation would result in indiscriminate coverage of the band. You could well end up with a channel (or several) that has no CleanAir coverage at all. However with the base installation, you would be using all of the channels available. Assuming RRM is in control (recommended) it is entirely possible that all of the CleanAir APs could be assigned to the same channel in a normal installation. You spread them out to try to get the best spatial coverage possible, and that actually increases the odds of this. You certainly can deploy a few CleanAir APs in with an existing installation. It is an AP and would function fine from a client and coverage standpoint. CleanAir functionality would be compromised and there is no way to really guarantee what the system would or would not tell you regarding your spectrum. There are far too many options in density and coverage which can be introduced to predict. What would work AQ would be valid for the reporting radio only. This means it is only relevant for the channel that it is serving, and this could change at any time. Interference alerts and zone of impact would be valid. However, any location derived would be suspect. Best to leave that out all together and assume closest AP resolution. Mitigation strategies would be ill-advised to operate because most of the APs in the deployment would not operate the same way. You would be able to use the AP to look at spectrum from Spectrum Connect. You would also have the option to temporarily switch to monitor mode at any time in order to perform a full scan of the environment. While there are some benefits, it is important to understand the pitfalls and adjust expectations accordingly. It is not recommended, and issues arising from this type of deployment are not supportable based on this deployment model. A better option if your budget does not support adding APs that do not serve client traffic (MMAP) is to collect enough CleanAir APs to deploy together in a single area. Any area that can be enclosed on a map area can contain a Greenfield CleanAir deployment with full feature support. The only caveat on this would be location. You still need enough density for location. While it is not advisable to mix legacy APs and CleanAir APs operating in local mode in the same deployment area, what about running both on the same WLC This is perfectly fine. Configurations for CleanAir are only applicable to APs that support CleanAir. For instance, in the RRM configuration parameters for both 802.11an and 802.11bgn you see both ED-RRM and PDA configurations for RRM. One might consider that these would be bad if applied to an AP that was not a CleanAir capable AP. However, even though these features do interact with RRM, they can only be triggered by a CleanAir event and are tracked to the AP that triggers them. There is no chance that a non - CleanAir AP has these configurations applied to them, even though the configuration applies to the whole RF group. This raises another important point. While CleanAir configurations on a 7.0 or later controller are effective for any CleanAir AP that attaches to that controller, ED-RRM and PDA are still RRM configurations. Implementation of CleanAir draws on many of the architecture elements present within the CUWN. It has been designed to fortify and add functionality to every system component, and draws on information that is already present top enhance usability and tightly integrate the features. This is the overall breakdown classified into license tiers. Notice that it is not necessary to have a WCS and or the MSE in the system to get good functionality from the system. The MIBs are available on the controller and are open to those who wish to integrate these features into an existing management system. For a basic CleanAir system, the requirements are a CleanAir AP and a WLC that runs version 7.0 or later code. This provides both a CLI and the WLC GUI for customer interface and all CURRENT data is displayed, including interference sources reported by band and the SE connect feature. Security Alerts (Interference sources designated as a security concern) are merged before triggering the SNMP trap. As previously stated though, WLC merging is limited to the view of just the APs associated to that controller. There is no historical support of trend analysis supported directly from the WLC interfaces. Adding a BASIC WCS and managing the controller adds trending support for AQ and alarms. You receive historical AQ reporting, threshold alerts through SNMP, RRM Dashboard support, Security alert support, and many other benefits including the client troubleshooting tool. What you do not get is Interference history and location. This is stored in the MSE. Note: Adding an MSE to the WCS for location requires both a WCS plus license and Context Aware feature licenses for the MSE. Adding an MSE and location solution to the network supports the historical IDR reporting as well as location based functions. In order to add this to an existing CUWN solution, you require a plus license on the WCS, and CAS or Context Aware licenses for the location targets. 1 Interferer 1 CAS license Interferers are managed through context aware and an interference that is tracked in the system is the same as a client for purposes of licensing. There are many options on how to manage these licenses and what they are used for. On the WLC configuration you can limit which interference sources are tracked for location and reporting in the maps by selecting them from the controller gt Wireless gt 802.11ba gt CleanAir menu. Interference devices selected there are reported, and choosing to ignore them keeps them out of the location system and MSE. This is completely separate from what is actually happening at the AP. All classifiers are always detected at the AP level. This determines what isdone with an IDR report. If you use this to limit reporting, then it is reasonably safe because all energy is still seen at the AP and is captured in AQ reports. AQ reports break out the contributing interference sources by category. If you eliminate a category here to conserve licensing, it is still reported as a contributing factor in AQ and you are alerted if you exceed a threshold. Figure 13: WLC CleanAir configuration - reporting For instance, suppose the network you are installing is in a retail environment, and the map is cluttered with Bluetooth targets coming from headsets. You could eliminate this by de-selecting the Bluetooth Link. If at some time later Bluetooth became a problem, you would see this category rise in your AQ reporting and could re-enable at will. There is no interface reset required. You also have the element manager under the MSE configurations: WCS gt Mobility Services gt Your MSE gt Context Aware Service gt administration gt tracking Parameters. Figure 14: MSE Context Aware element manager This gives the user complete control to assess and manage what licenses are used for and how they are divided among target categories. Table 7: CleanAir Features matrix by CUWN Component The minimum required configuration for Cisco CleanAir is the Cisco CleanAir AP, and a WLC which runs version 7.0. With these two components you can view all of the information provided by CleanAir APs. You also get the mitigation features available with the addition of CleanAir APs and the extensions provided through RRM. This information is viewable via the CLI or the GUI. The focus is on the GUI in this section for brevity. WLC Air Quality and Interference Reports On the WLC you can view current AQ and Interference reports from the GUI menu. In order to view interference reports, there must be interference active as the report is for current conditions only Interference Device Report Select Monitor gt Cisco CleanAir gt 802.11a802.11b gt Interference Devices. All active interference devices being reported by CleanAir Radios are listed by RadioAP reporting. Details include AP Name, Radio Slot ID, Interference Type, Affected Channels, Detected Time, Severity, Duty Cycle, RSSI, Device ID and Cluster ID. Figure 15: Accessing WLC Interference Device Report Air Quality Report Air Quality is reported by Radiochannel. In the example below, AP0022.bd18.87c0 is in monitor mode and displays AQ for channels 1-11. Selecting the radio button at the end of any line allows the option of showing this information in the radio detail screen, which includes all information gathered by the CleanAir interface. Figure 16: WLC Interference Device Report CleanAir Configuration AQ and Device Traps control CleanAir allows you to determine both the threshold and types of traps that you receive. Configuration is by band: Wireless gt 802.11ba gt CleanAir. Figure 17: WLC CleanAir configuration You can enable and disable CleanAir for the entire controller, suppress the reporting of all interferers, and determine which interferers to report or ignore. Selecting specific interference devices to ignore is a useful feature. For instance you might not want to track all Bluetooth headsets because they are relatively low impact and you have a lot of them. Choosing to ignore these devices simply prevents it from being reported. The RF that comes from the devices is still calculated into the total AQ for the spectrum. EnableDisable (on by default) the AirQuality trap. AQI Alarm Threshold (1 to 100). When you set the AirQuality threshold for traps, this tells the WLC at what level you want to see a trap for AirQuality. The default threshold is 35, which is extremely high. For testing purposes setting this value to 85 or 90 proves more practical. In practice, the threshold is variable so you can tune it for your specific environment. Enable Interference for Security Alarm. When you add the WLC to a WCS system, you can select this check box to treat interference device traps as security Alarm traps. This allows you to select the types of devices that appear in the WCS alarm summary panel as a security trap. Dodo not trap device selection allows control over the types of devices that generates interferencesecurity trap messages. Lastly, the status of ED-RRM (Event Driven RRM) is displayed. Configuration for this feature is covered under the Event Driven RRM - EDRRM section later in this document. Rapid Update Mode - CleanAir Detail Selecting Wireless gt Access Points gt Radios gt 802.11ab shows all of the 802.11b or 802.11a radios attached to the WLC. Selecting the radio button at the end of the line allows you to see either the radio detail (traditional non CleanAir metrics of utilization, noise and the like) or CleanAir detail. Figure 18: Accessing CleanAir Detail Selecting CleanAir produces a graphic (default) display of all CleanAir information pertaining to that radio. The information displayed is now in Rapid Update Mode by default. This means it is being refreshed every 30 seconds from the AP instead of the 15 minute averaging period displayed in system level messaging. From top to bottom, all interferers being detected by that radio along with the interference parameters of Type, Affected Channels, Detection Time, Severity, Duty Cycle, RSSI, Device ID, and Cluster ID. Figure 19: CleanAir Radio Detail Page From this figure, the displayed charts include: Air Quality by Channel Non - Wi-Fi Channel Utilization Air Quality by Channel displays the Air Quality for the channel that is being monitored. Non Wi-Fi channel utilization shows the utilization that is directly attributable to the interference device being displayed. In other words, if you get rid of that device you regain that much spectrum for Wi-Fi applications to use. There are two categories that are introduced here under Air Quality details: Adjacent Off Channel Interference (AOCI)This is interference from a Wi-Fi device that is not on the reporting operating channel, but is overlapping the channel space. For channel 6, the report would identify interference attributable to an AP on channels 4, 5, 7, and 8. UnclassifiedThis is energy that is not attributable definitively to Wi-Fi or non - Wi-Fi sources. Fragments, collisions, things of this nature frames that are mangled beyond recognition. In CleanAir guesses must not be made. Interference power displays the receive power of the interferer at that AP. The CleanAir Detail page displays information for all monitored channels. The examples above are from a Monitor Mode (MMAP) AP. A local Mode AP would show the same detail, but only for the current served channel. CleanAir Enabled RRM There are two key Mitigation Features that are present with CleanAir. Both rely directly on information that can only be gathered by CleanAir. Event Driven RRM Event Driven RRM (ED-RRM) is a feature that allows an AP in distress to bypass normal RRM intervals and immediately change channels. A CleanAir AP is always monitoring AQ, and reports on this in 15 second intervals. AirQuality is a better metric than relying on normal Wi-Fi chip noise measurements because AirQuality only reports on Classified Interference devices. This makes AirQuality a reliable metric because it is known what is reported is not because of Wi-Fi energy (and hence not a transient normal spike). For ED-RRM a channel change only occurs if the Air Quality is sufficiently impacted. Because Air Quality can only be affected by a classified known to CleanAir non - Wi-Fi source of interference (or an adjacent overlapping Wi-Fi channel), the impact is understood: Not a Wi-Fi anomaly A crisis condition at this AP Crisis means that CCA is blocked. No clients or the AP can use the current channel. Under these conditions RRM would change the channel on the next DCA pass. However, that could be a few minutes away (up to ten minutes depending on when the last run was performed), or the user could have changed the default interval and it could be longer (selected an anchor time and interval for longer DCA operation). ED-RRM reacts very quickly (30 seconds) so the users that change with the AP are likely unaware of the crisis that was close. 30 -50 seconds is not long enough to call a help desk. The users that do not are in no worse shape than they would have been in the first place. In all cases the interference source was identified and the AP change reason logs that source, and the users that have poor roaming receives an answer as to why this change was made. The channel change is not random. It is picked based on device contention, thus it is an intelligent alternate choice. Once the channel is changed there is protection against triggering ED-RRM again in a hold down timer (60 seconds). The event channel is also marked in RRM DCA for the affected AP to prevent a return to the event channel (3 hours) in the event the interferer is an intermittent event and DCA does not see it immediately. In all cases the impact of the channel change is isolated to the affected AP. Suppose a hacker or someone of ill intent fires up a 2.4 GHz jammer and all channels are blocked. First off, all the users within the radius are out of business anyway. However, suppose ED-RRM triggers on the all APs that can see it. All APs change channels once, then hold for 60 seconds. The condition would be met again, so another change would fire with the condition still being met after 60 seconds. There would be no channels left to change to and ED-RRM activity would stop. A security alert would fire off on the jammer (default action) and you would need to provide a location (if with MSE) or nearest detecting AP. ED-RRM would log a major AQ event for all affected channels. The reason would be RF jammer. The event would be contained within the effected RF domain and well alerted. Now the next question that is generally asked, quotwhat if the hacker walks around with the jammer, would that not that cause all the APs to trigger ED-RRMquot. Sure you are going to trigger ED-RRM channel changes on all the APs that have ED-RRM enabled. However, as the jammer moves so does its effect and usability is restored as soon as it moves. It really does not matter because you have a hacker walking around with a jammer in their hand disconnecting users everywhere they go. This is a problem in itself. ED-RRM does not compound that issue. CleanAir on the other hand is also busy alerting, locating, and providing the location history of where they went and where they are. These are good things to know in such a case. Configuration is accessed under Wireless gt 802.11a802.11b gt RRM gt DCA gt Event Driven RRM . Figure 20: Event Driven RRM Configuration Note: Once ED-RRM is triggered on an APChannel the AP is prevented from returning to that channel for three hours. This is to prevent thrashing if the signal source is intermittent in nature. Persistent Device Avoidance Persistent Device Avoidance is another mitigation feature that is only possible with CleanAir APs. A device that operates periodically, such as a microwave oven, can introduce destructive levels of interference while it is operating. However, once it is no longer in use the air goes quiet again. Devices such as video cameras, outdoor bridge equipment, and microwave ovens are all examples of a type of device called persistent. These devices can operate continuously or periodically, but what they all have in common is that they do not move frequently. RRM of course sees levels of RF noise on a given channel. If the device is operating long enough RRM even moves an active AP off the channel that has interference. However, once the device goes quiet, it is likely that the original channel presents as the better choice once again. Because each CleanAir AP is a spectrum sensor the center of the interference source can be evaluated and located. Also, you can understand which APs are affected by a device that you know is there, and potentially operates and disrupts the network when it does. Persistent Device Avoidance allows us to log the existence of such interference and remember that it is there so you do not place an AP back on the same channel. Once a Persistent Device has been identified it is remembered for seven days. If it is not seen again then it is cleared from the system. Each time you see it, the clock starts over. Note: Persistent Device Avoidance information is remembered at the AP and Controller. Rebooting either re-sets the value. Configuration for Persistent Device Avoidance is located at Wireless gt 802.11a802.11b gt RRM gt DCA gt Avoid Devices . In order to see if a radio has logged a Persistent Device you can view the status at Wireless gt Access Points gt Radios gt 802.11ab gt . Select a radio. At the end of the line click the radio button and select CleanAir RRM. Figure 21: CleanAir Persistent Device Avoidance status Spectrum Expert Connect CleanAir APs can all support the Spectrum Expert connect mode. This mode places the APs radios into a dedicated scanning mode that can drive the Cisco Spectrum Expert application across a network. The Spectrum Expert console functions as if it had a local Spectrum Expert card installed. Note: A routable network path must exist between the Spectrum Expert host and the target AP. Ports 37540 and 37550 must be open to connect. The Protocol is TCP, and the AP is listening. Spectrum Expert connect mode is an enhanced monitor mode, and as such the AP does not serve clients while this mode is enabled. When you initiate the mode the AP reboots. When it re-joins the controller it is in Spectrum Connect mode and have generated a session key for use to connect the application. All that is required is Cisco Spectrum Expert 4.0 or later, and a routable network path between the application host and the target AP. In order to initiate the connection, start by changing the mode on from Wireless gt Access Points gt All APs . Figure 22: AP Mode Configuration Go to AP Mode, and select SE-Connect. Save the configuration. You receive two warning screens: one advising that SE-connect mode is not a client-serving mode, the second warning that the AP is rebooted. Once you have changed the mode and saved the configuration navigate to the Monitor gt Access Points screen. Monitor the AP status and reload. Once the AP rejoins and reloads navigate back to the AP configuration screen, you need the NSI Key for the session that is displayed there. You can copy and paste the NSI key for the inclusion in launching Spectrum Expert. Figure 23: NSI Key generated You need Cisco Spectrum Expert 4.0. Once installed, launch Spectrum Expert. On the initial splash screen you see a new option, Remote Sensor. Select Remote Sensor and paste in the NSI Key, and tell Spectrum Expert the IP address of the AP. Select which radio you wish to connect to and click OK. Figure 24: Cisco Spectrum Expert Sensor connect screen When you add a WCS to the feature mix you get more display options for CleanAir information. The WLC can display current information, but with WCS the ability to track, monitor, alert, and report historical AirQuality levels for all CleanAir APs is added. Also, the ability to correlate CleanAir information to other award winning dashboards within WCS allows the user to fully understand their spectrum like never before. WCS CleanAir Dashboard The home page has several elements added and is customizable by the user. Any of the elements displayed on the home page can be re-arranged to user preferences. That is beyond the scope of this discussion, but keep it in mind as you use the system. What is being presented here is simply the default view. Selecting the CleanAir tab takes you to the CleanAir information available on the system. Figure 25: WCS Home Page Note: The default settings for the page include a top 10 interferers report by band in the right hand corner. If you do not have an MSE, this report does not populate. You can edit this page and add or delete components to customize it to your liking. Figure 26: WCS CleanAir Dashboard Charts displayed on this page display the running historical averages and minimums for CleanAir spectrum events. The average AQ number is for the entire system as displayed here. The minimum AQ chart for example tracks, by band, the minimum reported AQ received from any specific radio on the system in any 15 minute reporting period. You can use the charts to quickly identify historical minimums. Figure 27: Minimum Air Quality history chart Selecting the Enlarge Chart button on the bottom right in any chart object produces a pop-up window with an enlarged view of the chart in question. A mouse hover in any chart produces a time and date stamp, and AQ level seen for the reporting period. Figure 28: Enlarged Minimum Air Quality Chart Knowledge of the date and time gives you the information that you need to search for the particular event, and gather additional details such as APs that registered the event and device types operating at that time. AQ threshold alarms are reported to the WCS as performance alarms. You can also view them through the Alarm Summary panel at the top of the home page. Figure 29: Alarm Summary panel Either Advanced Search or simply selecting performance category from the alarm summary panel (provided you have a performance alarm) yields a list of performance alarms that contain details about a particular AQ event that is below the configured threshold. Figure 30: Air Quality Threshold Alarms Selecting a particular event displays the detail related to that event including the date, time, and most importantly the reporting AP. Figure 31: Performance Alarm Detail Configurations for Air Quality Thresholds is located under Configure gt Controller, either from the WCS GUI or the Controller GUI. This can be used for all CleanAir Configurations. The best practice is to use the WCS once you have assigned a controller to it. In order to generate performance alarms, you can set the AQ threshold for a low threshold such as 90 or even 95 (remember that AQ is good at 100 and bad at 0). You need some interference to trigger it such as a microwave oven. Remember to put a cup of water in it first and run it for 3-5 minutes. Air Quality History Tracking Reports AirQuality is tracked on each CleanAir AP at the radio level. The WCS enables historical reports for monitoring and trending AQ in your infrastructure. Reports can be accessed by navigating to the report launchpad. Select Reports gt Report Launchpad. CleanAir reports are at the top of the list. You can choose to look at Air Quality vs Time or Worst Air Quality APs. Both reports should be useful in tracking how Air Quality changes over time and identifying areas that require some attention. Figure 32: Report Launchpad CleanAir Maps Monitor gt Maps Selecting Monitor gt Maps displays the maps configured for the system. Average and minimum AQ numbers are presented in hierarchical fashion corresponding to the container levels of campus, building, and floor. For instance, at the building level the AverageMinimum AQ is the average of all CleanAir APs contained in the building. The minimum is the lowest AQ reported by any single CleanAir AP. Looking at a floor level, the average AQ represents the average of all APs located on that floor and the minimum AQ is that of the single worst AQ from an AP on that floor. Figure 33: Maps main page - showing Air Quality Hierarchy Selecting a map for a given floor provides detail relevant to the selected floor. There are a lot of ways that you can view the information on the map. For instance, you can change the AP tags to display CleanAir information such as CleanAir Status (shows which APs are capable), minimum or average AQ values, or Average and Minimum values. The values are relevant to the band selected. Figure 34: AP Tags show lots of CleanAir information You can see the interferers that are being reported by each AP in several ways. Hover over the AP, select a radio, and select the show interferers hotlink. This produces a list of all Interference detected on that interface. Figure 35: Viewing Interference Devices detected on an AP Another interesting way to visualize the impact of interference on the map is to select the interference tag. Without the MSE, you cannot locate interference on the map. However, you can select show interference labels, which are labels with the interferers currently being detected is applied to all CleanAir radios. You can customize this to limit the number of interferers displayed. Selecting the hotlink in the tab allows you to zoom in to the individual interferer details, and all interferers are displayed. Note: CleanAir APs can track unlimited numbers of interferers. They only report on the top 10 ordered by severity, with preference being given to a security threat. Figure 36: Interference Tag being displayed on all CleanAir APs A useful way to visualize non - Wi-Fi interference and its effect is to view AQ as a heatmap on the map display. Do this by selecting heatmaps and selecting Air Quality. You can display the average or the minimum AQ. The map is rendered using the coverage patterns for each AP. Notice that the upper right corner of the map is white. No AQ is rendered there because the AP is in monitor mode and passive. Figure 37: Air Quality Heat Map CleanAir Enabled RRM Dashboard CleanAir allows you to see what is in our spectrum that is non - Wi-Fi. In other words, all those things that were considered just noise can now be broken down to understand if and how it is impacting your data network. RRM can and does mitigate noise by selecting a better channel. When this occurs the solution is generally better than it was, but you are still letting something that is not your data network occupy your spectrum. This reduces the overall spectrum available to your data and voice applications. Wired and Wireless networks differ in that on a wired network if you need more bandwidth you can install more switches, or ports, or Internet connections. The signals are all contained within the wire and do not interfere with one another. In a wireless network, however, there is a finite amount of spectrum available. Once used, you cannot simply add more. The CleanAir RRM Dashboard on the WCS allows you to understand what is going on in your spectrum by tracking non - Wi-Fi interference as well as Signal from our network, Interference from foreign networks and balancing all within the spectrum that is available. The solutions that RRM provides do not always seem optimal. However, there is often something that you cannot see which causes two APs to operate on the same channel. The RRM Dashboard is what we use to track events that affect the balance of spectrum and provide answers as to why something is the way it is. CleanAir information being integrated to this dashboard is a big step forward to total control of the spectrum. Figure 38: CleanAir RRM Channel Change reasons from RRM Dashboard Channel Change reasons now include several new categories which refine the old Noise category (anything that is not Wi-Fi is recognized as noise by Cisco and all other competitors): Noise (CleanAir) represents non - Wi-Fi energy in the spectrum as being a cause or a major contributor to a channel change. Persistent Non-WiFi interference indicates that a persistent interferer has been detected and logged on an AP, and the AP changed channels to avoid this interference. Major Air Quality Event is the reason for a channel change invoked by the Event Driven RRM feature. Other there is always energy present in the spectrum that is not demodulated as Wi-Fi, and cannot be classified as a known interference source. The reasons for this are many: the signals are too corrupted to separate, left over remnants from collisions is one possibility. Knowing that non-WiFi interference is affecting your network is a big advantage. Having your network know and act on this information is a big plus. Some interference you are able to mitigate and remove, some you do not (in the case of a neighbors emissions). Typically most organizations have interference at one level or another, and a lot of this interference is low level enough to not pose any real problems. However, the busier your network gets the more it needs an unaffected spectrum. CleanAir Enabled Security Dashboard Non-Wi-Fi devices can offer quite a challenge to wireless security. Having the ability to examine signals at the physical layer allows for much more granular security. Normal every day consumer wireless devices can and do bypass normal Wi-Fi security. Because all existing WIDsWIPs applications rely on Wi-Fi chipsets for detection, there has been no way to accurately identify these threats until now. For instance, it is possible to invert the data in a wireless signal so that it is 180 degrees out of phase from a normal Wi-Fi signal. Or, you could change the center frequency of the channel by a few kHz and as long as you had a client set to the same center frequency you would have a private channel that no other Wi-Fi chip could see or understand. All that is required is access to the HAL layer (many are available under GPL) for the chip and a little bit of skill. CleanAir is able to detect and understand what these signals are. In addition, CleanAir can detect and locate a PhyDOS attack such as RF Jamming. You can configure CleanAir to report any device that is classified as a security threat. This allows the user to determine what should and should not be transmitting within their facility. There are three ways to view these events. The most convenient is through the Alarm Summary panel located at the top of the WCS home page. A more detailed analysis can be gained by using the Security Dashboard tab on the main page. This is where all security related information on the system is displayed. CleanAir now has its own section within this dashboard allowing you to gain a full understanding of the security of your network from all wireless sources. Figure 39: Security Dashboard with CleanAr integration No matter where you view this information from, you have the detecting AP, the time and date of the event, and the current status to work with. With an MSE added you can run periodic reports on just CleanAir security events. Or, you can look at the location on the map and see the history of the event, even if it was moving. CleanAir enabled Client Troubleshooting Dashboard The client dashboard on the WCS home page is the one stop for all things for clients. Because interference often affects a client before it affects the AP (lower power, poorer antennas) a key thing to know when troubleshooting client performance issues is if non - Wi-Fi interference is a factor. CleanAir has been integrated to the Client Troubleshooting tool on the WCS for that reason. Access the client information in any way you choose from the dashboard, either by searching on a MAC address or user. Once you have the client displayed, select the Client Troubleshooting tool Icon to launch the Client Troubleshooting Dashboard. Figure 40: Client Troubleshooting Dashboard - with CleanAir The client tools provide a wealth of information about the clients status on the network. Select the CleanAir tab on the Monitor Client screen. If the AP that the client is currently associated to is reporting any interference, it is displayed here. Figure 41: CleanAir tab from Client Troubleshooting tool In this case, the interference being detected is a DECT like phone, and because the severity is only 1 (very low) it would be unlikely to cause a lot of trouble. However, a couple of Severity 1 devices can cause issues for a client. The Client Dashboard allows you to quickly rule out, as well as prove, issues in a logical fashion. The MSE adds a significant amount of information to CleanAir features. The MSE is responsible for all location calculations, which are much more intensive for non-Wi-Fi interference than for a Wi-Fi target. The reason for this is the range of conditions that location has to work with. There are a lot of non-Wi-Fi interferers in the world, and they all operate differently. Even among similar devices there can be great differences in signal strength or radiation patterns. The MSE is also who manages merging of devices that span multiple controllers. If you recall, a WLC can merge devices that APs reports, which it is managing. But, interference can be detected that is present on APs that are not all on the same controller. All of the features that MSE enhances are located only in the WCS. Once you have located an interference device on a map, there are several things that can be calculated and presented about how that interference interacts with your network. WCS CleanAir Dashboard with MSE Previously in this document, the CleanAir Dashboard and how the top 10 interferers per band would not be displayed without the MSE was discussed. With the MSE, these are now active because you have the interference device and location information from the MSEs contribution. Figure 42: MSE enabled CleanAir dashboard The upper right hand tables are now populated with the 10 most severe interference sources detected for each band: 802.11an and 802.11bgn. Figure 43: Worst Interference for 802.11an The information displayed is similar to that of the interference report from a specific AP. Interference ID this is the database record for the interference on the MSE Type the type of interferer being detected Status currently only displays Active interferers Severity the severity calculated for the device Affected Channels the channels that the device is being seen affecting Discovered last updated time stamps Floor the map location of the interference If you choose the floor location, it hotlinks you to the map display of the interference source directly where much more information is possible. Note: There is one other difference beyond having a location between information displayed about interferers over what you can see on the AP radio level directly. You might have noticed that there is no RSSI value for the interference. This is because the record as seen here is merged. It is the result of multiple APs reporting the device. The RSSI information is no longer relevant, nor would it be correct to display it because each AP sees the device at different signal strength. WCS Maps with CleanAir device location Choose the link at the end of the record in order to navigate directly to the map location of the interference device from the CleanAir dashboard. Figure 44: Interference located on the map Now locating the interference source on the map allows us to understand its relationship to everything else on the map. In order to product specific information about the device itself (see figure 36), pass a mouse over the interference Icon. Notice the detecting APs, this is the list of APs that currently hears this device. The cluster Center is the AP that is closest to the device. The last line shows the Zone of Impact. This is the radius that the interference device would be suspected of being disruptive. Figure 45: Interference Detail from Mouse Hover The Zone of Impact is only half the story though. It is important to remember that a device might have a long reach or large zone of impact. However, if the severity is low it might or might not matter at all. Zone of impact can be viewed on the map by selecting Interferers gt Zone of Impact from the map display menu. Now you can see the Zone of Impact (ZOI) on the map. ZOI is rendered as a circle around the detected device, and its opacity darkens with higher severity. This aids visualizing the impact of interference devices greatly. A small dark circle is much more of a concern than a large translucent circle. You can combine this information with any other map display or element that you choose. Double-clicking on any interference icon takes you to the detail record for that interference. Figure 46: MSE Interference Record Interferer details include a lot of information about the type of interferer that is being detected. In the upper right hand corner is the help field which tells about what this device is and how this particular type of device affects your network. Figure 47: Detailed Help Other workflow links within the detail record include: Show Interferers of this Type links to a filter to show other instances of this type of device Show Interferers affecting this band links to a filtered display of all same band interferers Floor links back to the map location for this device MSE links to the reporting MSE configuration Clustered by links to the controllers that performed the initial merge Detecting APs hot links to the reporting APs for use in viewing the interference directly from the AP details Interference Location History From the command window in the upper right corner of the record display you can select to view the location history of this interference device. Location History shows the position and all relevant data such as timedate and detecting APs of an interference device. This can be extremely useful in understanding where the interference has been detected and how it has behaved or impacted your network. This information is part of the permanent record of the interference in the MSE database. WCS Monitor Interference The contents of the MSE interferer database can be viewed directly from the WCS by selecting Monitor gt Interference. Figure 48: Monitor Interferers display The list is sorted by status by default. However, it can be sorted by any of the columns contained. You might notice that RSSI information on the interferer is missing. This is because these are merged records. Multiple APs hear a particular interference source. All of them hear it differently, so severity replaces RSSI. You can select any interference IDs in this list to display the same detailed record as was discussed above. Selecting the device type produces the help information that is contained within the record. Selecting the floor location takes you to the map location of the interference. You can select Advanced Search and query the Interferers database directly, then filter the results by multiple criteria. Figure 49: Advance Interference Search You can choose all interferers by ID, by Type (includes all classifiers), severity (range), Duty Cycle (range) or location (floor). You can select the time period, the status (ActiveInactive), select a specific band or even a channel. Save the search for future use if you like. There are two basic types of information generated by the CleanAir components within the system: Interference Device Reports and AirQuality. The controller maintains the AQ database for all attached radios and is responsible for generating threshold traps based on the users configurable thresholds. The MSE manages Interference Device Reports and merges multiple reports arriving from controllers and APs that span controllers into a single event, and locates within the infrastructure. The WCS displays information collected and processed by different components within the CUWN CleanAir system. Individual information elements can be viewed from the individual components as raw data, and the WCS is used to consolidate and display a system wide view and provide automation and work flow. CleanAir installation is a straightforward process. Here are some tips on how to validate the functionality for an initial installation. If you upgrade a current system or install a new system, the best order of operations to follow is Controller code, WCS code, then add MSE code to the mix. Validation at each stage is recommended. In order to enable CleanAir functionality in the system, you first need to enable this on the controller through Wireless gt 802.11ab gt CleanAir . Ensure CleanAir is enabled. This is disabled by default. Once enabled it takes 15 minutes for normal system propagation of Air Quality information because the default reporting interval is 15 minutes. However, you can see the results instantly at the CleanAir detail level on the radio. Monitor gt Access Points gt 802.11an or 802.11bn This displays all radios for a given band. CleanAir status is displayed in the CleanAir Admin Status and CleanAir Oper Status columns. Admin Status relates to the radio status for CleanAir should be enabled by default Oper Status relates to the state of CleanAir for the system this is what the enable command on the controller menu mentioned above controls The operational status cannot be up if the admin status for the radio is disabled. Assuming that you have an Enable for Admin Status, and Up for Operational Status, you can select to view the CleanAir details for a given radio using the radio button located at the end of the row. The selection of CleanAir for details places the radio into Rapid Update mode and provides instant (30 second) updates to Air Quality. If you get Air Quality then CleanAir works. You might or might not see interferers at this point. This depends if you have any active. As previously mentioned, you do not have Air Quality reports for up to 15 minutes displaying in the WCS gt CleanAir tab after initially enabling CleanAir. However, Air Quality reporting should be enabled by default and can be used to validate the installation at this point. In the CleanAir tab you do not have interferers reported in the worst 802.11ab categories without an MSE. You can test an individually interference trap by designating an interference source that you can easily demonstrate as a security threat in the CleanAir configuration dialogue: Configure gt controllers gt 802.11ab gt CleanAir. Figure 50: CleanAir configuration - Security Alarm Adding an interference source for a Security Alarm causes the controller to send a trap message on discovery. This is reflected in the CleanAir tab under the Recent Security-risk Interferers heading. Without the MSE present you do not have any functionality for Monitor gt Interference. This is driven purely by the MSE. There is nothing particularly special about adding an MSE to the CUWN for CleanAir support. Once added, there are some specific configurations you need to make. Ensure that you have synchronized both the system maps and controller before you enable CleanAir tracking parameters. On the WCS console, choose Services gt Mobility Services gt select your MSE gt Context Aware Service gt Administration gt Tracking Parameters . Choose Interferers to enable MSE interference tracking and reporting. Remember to save. Figure 51: MSE Context Aware interference configuration While in the Context Aware Services Administration menu, also visit History Parameters and enable Interferers here as well. Save your selection. Figure 52: Context Aware History Tracking Parameters Enabling these configurations signals the synchronized controller to start the flow of CleanAir IDR information to the MSE and initiates the MSE tracking and convergence processes. It is possible to get the MSE and a controller out of synchronization from a CleanAir perspective. This can happen during an upgrade of controller code when interference sources from multiple controllers might get bounced (deactivated, and re-activated). Simply disabling these configurations and re-enabling with a save forces the MSE to re-register with all synchronized WLCs. Then, the WLCs send fresh data to the MSE, effectively re-starting the processes of merging and tracking of interference sources. When you first add an MSE, you must synchronize the MSE with the network designs and WLCs that you wish for it to provide services for. Synchronization is heavily dependent on Time. You can validate synchronization and NMSP protocol functionality by going to Services gt Synchronization services gt Controllers. Figure 53: Controller - MSE Synchronization Status You see the sync status for each WLC you are synchronized with. A particularly useful tool is located under the MSE column heading NMSP Status. Selecting this tool provides a wealth of information about the state of the NMSP protocol, and can give you information on why a particular synchronization is not occurring. Figure 54: NMSP Protocol Status One of the more common issues experienced is that the time on the MSE and WLC are not the same. If this is the condition, it is displayed in this status screen. There are two cases: WLC Time is after the MSE timeThis synchronizes. But, there are potential errors when merging multiple WLCs information. WLC time is before the MSE timeThis does not allow synchronization because the events have not occurred yet according to the MSEs clock. A good practice is to use NTP services for all controllers and the MSE. Once you have the MSE synchronized and CleanAir enabled, you should be able to see Interference sources in the CleanAir tab under Worst 802.11ab interferers. You can also view them under Monitor gt Interference, which is a direct display of the MSE interference database. One last potential gotcha exists on the Monitor Interferers display. The initial page is filtered to only display interferers that have a severity greater than 5. Figure 55: WCS - Monitor Interferers display This is stated on the initial screen, but often goes overlooked when initializing and validating a new system. You can edit this to display all interference sources by simply making the severity value 0. There are many terms used in this document that are not familiar to a lot of users. Several of these terms come from Spectrum Analysis, some are not. Resolution Band Width (RBW), the minimum RBWThe minimum band width that can be accurately displayed. SAgE2 cards (including the 3500) all have 156 KHz minimum RBW on a 20 MHz dwell, and 78 KHz on a 40 MHz dwell. DwellA dwell is the amount of time the receiver spends listening to a particular frequency. All lightweight access points (LAPs) do off channel dwells in support of rogue detection and metrics gathering for RRM. Spectrum Analyzers do a series of dwells to cover a whole band with a receiver that only covers a portion of the band. DSPDigital Signal Processing SAgESpectrum Analysis Engine Duty CycleDuty Cycle is the active on time of a transmitter. If a transmitter is actively using a particular frequency, the only way another transmitter can use that frequency is to be louder than the first, and significantly louder at that. A SNR margin is needed to understand it. Fast Fourier Transform (FFT)For those interested in the math, google this. Essentially, FFT is used to quantify an analog signal and convert the output from the Time domain to the Frequency domain.
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