Optimizing wlan operations peter lane

CONFIDENTIAL
© Copyright 2013. Aruba Networks, Inc.
All rights reserved 1 #airheadsconf#airheadsconf
Optimizing WLANs
Peter Lane
March 14, 2013

CONFIDENTIAL
All rights reserved 2 #airheadsconf
Inventory your network
Monitor the health of your network
Alert on critical issues
Optimize RF
Optimize Applications
Agenda

CONFIDENTIAL
•  Voice/video optimization
•  High Density/Large Public Venue
•  Outdoor
•  Advanced RF troubleshooting
Topics not covered

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•  APs
–  Single radio or dual radio
–  a/b/g, 2 stream 11n, 3 stream 11n
•  Switches
–  AP uplink speed
–  Switch uplink speed
•  Applications
–  Voice
–  Video
–  Cloud based (Salesforce, Box, Hulu, YouTube, etc.)
–  Gaming
–  File sharing
Routinely Inventory your network

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•  Clients
–  Types
–  Densities
–  Locations
•  Physical locations
–  Odd construction materials
–  Old buildings
–  Sources of Interference
Routinely Inventory your network

6 6
CONFIDENTIAL
All rights reserved
ArubaOS Dashboard - Performance
Noise Floor
Channel Utilization
Interference
SNR

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AOS RF Dashboard – Security

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AOS RF Dashboard – WLAN

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AOS RF Dashboard – Access Points

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AirWave – AP Monitoring

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Radio Details

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AppRF AirWave Screenshots

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•  Prioritize cloud based Applications
–  Create a stateful firewall destination
–  Add a policy using that destination to prioritize
–  Pause ARM scanning for extremely latency sensitive or UDP
heavy applications (not common)
Controller ACLs and policy updates

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•  Limit the bandwidth per user/role
•  Limit the bandwidth used per VAP.
Bandwidth contracts and Traffic shaping

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Use Reports to identify trends over time

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RF Health

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Rogue Client Connections
•  Don’t get blamed for
other networks
performance
•  Identify clients that
are misconfigured
•  Identify underserved
locations

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Capacity planning

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Use alerts to reduce work and gain
visibility

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Channel Utilization
•  Why is the Radio low on
air time?
–  Special event
–  Other APs down
–  Change in user behavior
–  Lots of multicast
•  Frequent occurrence?
–  Add APs
–  Upgrade APs
–  Implement bandwidth contracts
–  AirGroup

CONFIDENTIAL
•  >-85 is a concern
–  Look at the SNR of
associated clients to
determine impact
•  Look at nearby APs
–  Is it an area wide problem or
restricted to a single AP?
Noise Floor monitoring

CONFIDENTIAL
Radius Auth Issues
•  Find Auth issues before
clients report them
–  Restrict to Device or user
–  Tweak levels for your
environment
–  Verify RADIUS server
performance and config if
problems are seen

CONFIDENTIAL
IDS Events can cause client disruption
•  Some attacks simply
disrupt the network
–  Very rare
–  Not an issue if only seen
once
–  Repeated detections imply
someone is causing network
problems
–  Don’t waste time looking for
other problems when this one
is purposely created

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Interface Usage Monitoring
•  A saturated uplink leads
to slow wireless
performance

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Device Event Monitoring
•  Catchall Alert
–  Temp
–  Fan speed
–  Crash
–  Etc.

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•  Sticky clients
–  Station handoff assist
–  Lower TX power levels
•  Interference
–  Non-wifi interference immunity (use with caution)
–  Channel Reuse and Cell size reduction
–  Lower TX power levels
–  ARM channel changes
–  Replace microwaves
•  Old clients
–  Match AP min/max TX power to +- 3 db of client
Common Problems

CONFIDENTIAL
Standard recommendations from VRD
Feature Setting Profile
ARM Assignment Single band (default)
Multiband (for single-radio APs)
ARM
Client-Aware ARM Enabled ARM
Voice-Aware Scanning Enabled ARM
Video-Aware Scanning Enabled ARM
Load-Aware Scanning 10 Mb/s (default) ARM
Power-Save-Aware
Scanning
Disabled ARM
Rogue-Aware Scanning Disabled except for high security
environments
ARM
Band Steering Enabled, prefer 5 GHz (default) VAP
Adjusting Receive
Sensitivity
Disabled Radio
Station Handoff Assist Disabled RF Optimization
Intelligent Rate
Adaptation
Always on, not configurable N/A
Fair Access Enabled Radio

CONFIDENTIAL
Deployment specific settings from
the VRD
Feature
Sparse AP
with Data Only
Dense AP
with Data Only
When
Enabling Video
When
Enabling Voice
Spectrum Load
Balancing
Disabled Enabled Enabled Disabled
Mode-Aware ARM Disabled Disabled Disabled Enable only to
solve client issues
Local Probe Request
Threshold
Disabled Enabled (value =
25 dB)
Enabled (value =
25 dB)
Enabled (value =
25 dB)
Dynamic Multicast
Optimization
Disabled Disabled Enabled – higher
of 40 or 3 x
number of VLANs
Disabled

CONFIDENTIAL
•  Know your network
–  How is it used
–  Where is it used
•  Monitor the health of your network
–  RF health of the APs
–  Client health
–  Authentication issues
•  Alert on critical issues
–  Leverage tools to get notified about issues
Keep Optimizing

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Thank You

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•  AP Characteristics
–  Number and type of Radios (a/b/g/n)
–  Max Tx Power
–  Receive Sensitivity
–  Number of Spatial Streams
–  Antenna – Internal/External
–  Antenna Pattern
–  Number of clients supported
What Affects Signal Strength?
APs are not created equal
Choose the right AP for the occasion

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AP-135 Antenna Pattern

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AP-93 Antenna Pattern

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AP Radiated Power (EIRP)
= Radio Transmit Power (dBm)
+ Transmit Antenna Gain (dBi)
•  AP Regulatory Domain
•  Country Code
•  Radio Band (2.4GHz/5GHz)
•  Channel (different channel has different
allowed Max EIRP)
Antenna is PASSIVE – Does Not ADD energy
Higher Gain just means energy more focused
Not always a good thing

CONFIDENTIAL
•  Attenuation (Path Loss)
–  Distance from AP/Line-of-sight
–  Building materials (walls, windows, partitions)
–  Furniture
–  People
Client Received Power (dBm)
= Radiated Power/EIRP (dBm)
- Path Loss (dB)
+ Receiver Antenna Gain (dBi)

CONFIDENTIAL
Attenuation of Common Building Material
2.4GHz 5.0GHz
Fabric, blinds, ceiling tiles ~1dB ~1.5dB
Interior drywall 3-4 dB 3-5 dB
Cubicle wall 2-5 dB 4-9 dB
Wood door (Hollow – Solid) 3-4 dB 6-7 dB
Brick/Concrete wall 6-18 dB 10-30 dB
Glass/Window (not tinted) 2-3 dB 6-8 dB
Double-pane coated glass 13 dB 20 dB
Steel/Fire exit door 13-19 dB 25-32 dB

CONFIDENTIAL
•  Disable Bcast if possible
•  AirGroup when possible
–  Management frames
–  Lowest data rates
–  Large subnets bring in large bcast domains
•  SSID profile
–  Bcast/mcast on the SSID
•  Set to ARP
Broadcast Optimization

CONFIDENTIAL
•  Watch out for DHCP lease issues
•  Short leases recommended depending on usage
–  30-60 min for guest networks
–  6 to 8 hours for .1x
DHCP

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