LARGE PUBLIC VENUES DESIGN PRACTICES
DIRK LANSSENS
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LARGE PUBLIC VENUE WIRELESS
A perfect storm of devices and applications
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LARGESpace
PUBLICTypes
VENUES
–
Area Per Person
• Stadiums – generally outdoor, domes
• Open Fields – outdoor
• Arenas – generally indoor
• Convention Centers – Keynotes, Classrooms, Exhibition Halls
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THE LARGE PUBLIC VENUE CHALLENGES
Scalability to
match different
performance
needs
High user and
device density
RF spectrum
management
Flexibility for
temporary
events
Minimize
installation time
and cost
Unpredictable
devices – BYOD
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Adapt
infrastructure to
match client
types
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APPLICATION PERFORMANCE REQUIREMENTS
Design guidelines for average bandwidth per client
Application
Average Bandwidth
Basic Internet access
1Mbps
High quality streaming video
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2-4Mbps
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WI-FI CAPACITY DESIGN
Guidelines for users per radio
• High performance – instructional, demos, etc.
= 15-25
- Array/AP dedicated to demos/key note.
• High density – general Internet access
= 60-100
• Expected simultaneous clients / 70 = number of total radios needed
per location
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DESIGN PRINCIPALS – OTHER CONSIDERATIONS
1.
Maximize 5GHz
Band steer devices to 5GHz if they support, minimize 2.4GHz use
2.
Disable 11n bonding
Maximizes number of 5GHz channels for the design. It’s all about frequency re-use.
3.
Limit SSID count
Each adds significant overhead to the Wi-Fi channel
4.
Turn off 11b
Very few 11b only clients out there, negatively impacts performance
5.
Filter traffic
Keep peer-to-peer, broadcasts, netbios, Bonjour, etc. off the air
6.
Rate limit clients
Use in case by case basis per BW requirements
7.
IP addressing
Ensure big enough space allocated and DHCP lease times limited
8.
Identify possible L3 network boundaries
9.
Ensure sufficient pipe size to Internet, oversubscription ratio
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DESIGN PRINCIPALS - CONTINUED
Wi-Fi must be optimized to deliver predictable user experience
10. Channel Plan – Verify Auto channel results in high density
11. Right design RF for specific areas in the Facility
Use AP’s where appropriate and use external directional antennas where
required for high density small zones and greater RF control is required.
a. Bowl or Stadium Seating
b. Concourse, Suites, Parking lots, Offices, Classrooms
12. Physical location of AP’s to devices.
13. Use all available mounting locations, beams, rails, walls, underneath seats
14. Baseline survey each area before final design. Identify potential RF issues
15. 30-50% concurrency is a typical for LPV environments.
16. Captive Portals can be a hassle
17. Implement a Wireless policy
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CHALLENGE
CCI
Space– Types
– Area Per Person
• Co-channel Interference is the largest obstacle to a successful
LPV deployment
• CCI is the overlap of cells from different APs or Clients utilizing
the same channel
• Most ignore impact of client CCI and only focus on AP CCI
• Finding balance between good client RSSI, minimal CCI, and
number of radios to meet BW requirements is number 1
challenge
• Channel plan takes into account AP CCI as well as client device
CCI.
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KEYNOTE ARRAY PLACEMENT EXAMPLE
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KEYNOTE ARRAY PLACEMENT EXAMPLE
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STADIUMS
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SAMPLE WI-FI POLICY
Cause
Policy
Co-channel Interference caused by rogue
devices transmitting on the same or
overlapping channels
Implement a zero tolerance policy through
initial contract with customer. Use a tool to
locate and mitigate rogues at the start of and
during events.
Excessive 2.4GHz noise in a very dense
environment can cause the network to be
unusable.
Less is more when deploying 2.4GHz radios.
It is recommended to offer 2.4GHz service on
a separate SSID on a limited number of
radios.
Oversubscription of available bandwidth.
Limit Wi-Fi bandwidth to 1Mbps per user.
Exhibitors or internal networks can be given
more bandwidth if needed.
Hotspots causing interference.
These should also be contractually banned
when possible.
WLAN reaches capacity per design and SLA.
As venues and needs grow, so does the
impact on the network. Keeping a number of
AP’s on standby will enable a proactive
response.
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