Aruba Networks Version 3.3 manual

Page 57

The ARM system handles setting all power and channel setting, including moving the APs to new channel and power settings automatically when appropriate. The network administrator spends no time managing the RF environment even in the case of RF jamming attacks or interference from legitimate wireless sources in the same frequency. The system automatically determines the best settings, and can automatically move away from interference laden channels without any intervention. The ARM system works indoors or outdoors.

Sometimes a channel change is desirable but to do so would interrupt active user sessions. Certain types of devices are more tolerant of such changes than others. Because the Mobility Controller is aware of not only users on the AP but also the type of traffic being sent, the AP can be directed not to change channels for specific client types. It can be set to pause scanning if going off channel will cause unacceptable quality disruption. These features are called Client Aware and Voice Aware Scanning.

Aruba Client Aware Scanning prevents a channel change while clients are associated with a particular AP. This ensures that clients will continue to send and receive data without the AP suddenly switching to a new channel. When all clients have left a particular AP, it is free to change channels. While the client is attached, it will continue to go off channel for scanning at predetermined intervals unless ARM scanning is disabled.

If the customer has chosen not to deploy dedicated Air Monitors, the system can still obtain the information it needs to conduct basic WIPS and ARM functions by ‘timesharing’ with the data traffic on each AP. This scanning is transparent to data users, but can have detrimental effects on isochronous traffic flows such as voice calls. With Aruba Voice Aware Scanning, in the optional Voice Services Module, the AP will temporarily stop channel scanning when calls are in progress. Because the Mobility Controller is aware of the state of the call, it will pause scanning when the phone goes “off hook” and resume scanning when the call ends.

ARM is typically run in a very aggressive mode when the network is first deployed, allowing the APs to quickly settle their power and channel settings. The following setting should be used to initially settle the network infrastructure, and should be configured in a new profile:

Parameter

Value

---------

-----

Assignment

single-band

Client Aware

Disabled

Max Tx Power

30

dBm

Min Tx Power

11

dBm

Multi Band Scan

Disabled

Rogue AP Aware

Disabled

Scan Interval

1 sec

Scanning

Enabled

Scan Time

110 msec

Power Save Aware Scan

Disabled

Ideal Coverage Index

5

 

Acceptable Coverage Index

2

 

Wait Time

2 sec

Free Channel Index

25

 

Backoff Time

120 sec

Error Rate Threshold

50

%

Error Rate Wait Time

30

sec

Noise Threshold

75

-dBm

Noise Wait Time

120 sec

Minimum Scan Time

2 sec

 

 

 

Campus Wireless Networks Validated Reference Design Version 3.3 Design Guide

RF Planning and Operation 57

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Contents Campus Wireless Networks Validated Reference Design Version Crossman Avenue Sunnyvale, California Phone Fax Contents Chapter RF Planning and Operation Reference Documents Aruba Reference ArchitecturesContacting Aruba Networks IntroductionTelephone Support Aruba’s User-Centric Network Architecture Understanding Centralized Wireless LAN NetworksCentralized Wlan Model Introducing Aruba’s User-Centric NetworkArubaOS ArubaOS and Mobility ControllerMobility Controller Multi-function Thin Access Points Access PointAir Monitor Aruba’s Secure Enterprise Mesh Network Mesh Portal or Mesh PointRemote AP Mobility Management SystemMobility Management System Proof-of-Concept Network PoC Network Physical DesignVlan PoC Network Logical and RF DesignProof-of-Concept Network Proof-of-Concept Network Campus Wlan Validated Reference Design Aruba Campus Wlan Physical ArchitectureAruba Campus Wlan Logical Architecture Data center ManagementMaster Campus Wlan Validated Reference Design Understanding Master and Local Operation Mobility Controller Access Point DeploymentMobility Controller High Availability Master Controller Redundancy Local Controller Redundancy Second Local controller has an opposite configuration Vlan Design Do Not Use Special VLANs Do Not Make Aruba the Default RouterVlan Vlan PoolsVLANs 10, 20, 30 User Mobility and Mobility DomainsMD1 ArubaOS Mobility DomainMaster Controller Placement Mobility Controller Physical Placement and ConnectivityAP Placement, Power, and Connectivity Local Controller PlacementMobility Controller and Thin AP Communication AP Power and Connectivity AP Location and Density ConsiderationsOffice Deployment Active Rfid Tag Deployment Voice DeploymentMobility Controller Configuration Configuration Profiles and AP GroupsConfiguration Profiles Required LicensesAP group Profile TypesSSIDs, VLANs and Role Derivation AP GroupsProfile Planning VLANs SSIDsRole Derivation Secure Authentication MethodsAuthenticating with Corporate Authentication Methods for Legacy Devices Authenticating with Captive PortalEmployee Role Configuring Roles for Employee, Guest and Application UsersGuest Role Create a bandwidth contract and apply it to an AP group Create the block-internal-access policy Modify the guest-logon role Device Role Wireless Intrusion Detection System Role Variation by Authentication MethodWireless Attacks Rogue APs Page Mobility Controller Configuration RF Planning and Operation RF Plan ToolAdaptive Radio Management Page Minimum Scan Time Sec Voice over Wi-Fi Quality of ServiceWMM and QoS Traffic Prioritization Voice Functionality and FeaturesNetwork Wide QoS Voice-Aware RF ManagementComprehensive Voice Management Voice over Wi-Fi LAN / WAN Controller Clusters Mobility Management SystemMultiple Master/Local Clusters Page Multiple Master/Local Clusters Licenses Appendix aLicenses Wlan Extension with Remote AP Appendix BWlan Extension with Remote AP Alternative Deployment Architectures Small Network DeploymentMobility Controller located in the network data center Medium Network DeploymentBranch Office Deployment Corporate data center DMZ Pure Remote Access Deployment
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