27
Mobility at CERN
29/10/2013 HEPiX Fall 2013 2
IT/Communication Systems
HEPiX Fall 2013
Agenda• Evolution of Wi-Fi at CERN• BYOD impact• Special Wi-Fi deployments• Eduroam@CERN
29/10/2013 HEPiX Fall 2013 3
Development of the CERN Wi-Fi
29/10/2013 HEPiX Fall 2013 4
4,000 simultaneous users
1,400 Access points
280,000m2 covered
7,000 unique devices per day
7 Gbps of traffic
Early 2007
x 6 Devices in 6 years
Wi-Fi is complex
29/10/2013 HEPiX Fall 2013 5
The challenges:
- client related issues
- infrastructure issues:- deployment challenges- sources of interference
- (high) density issues
- a combination of all factors
- expected QoS from the user’s point of view
Challenges: client issues
29/10/2013 HEPiX Fall 2013 6
Challenges: a diverse infrastructure
29/10/2013 HEPiX Fall 2013 7
Challenges: A large and dynamic environment
• 600,000m2 indoor area (+20% in 6 years)• 650 surface buildings (+15% in 6 years)• 2,100,000m2 outside area (stable)
• New experiments• Building refurbishment
HEPiX Fall 2013 829/10/2013
Challenges: intensive usage• From an extension of the structured cabling
to fundamental service
HEPiX Fall 2013 929/10/2013
The primary connection for an increasing number of devices
How do we address this?
HEPiX Fall 2013 1029/10/2013
Optimizing RF spectrum!
• Migration from 802.11bg to 802.11n 5GHz• Up to 240Mbps half-duplex shared
• From 200m2 per AP to 120m2 (-40% )• Increase the density of APs
HEPiX Fall 2013 11
Avoid the 2.4GHz Band where possible
29/10/2013
Turning ON is not enough• Band steering • Load balancing • Auto-channel assignment• Auto-power tuning
HEPiX Fall 2013 12
Might not work out of the box
RF planning and site survey still required
Wi-Fi tuning necessary
29/10/2013
Automation for scalability
HEPiX Fall 2013 13
Automated RF configuration
Simplify
Save resources
Increase reliability
Data Base
Network Management System
29/10/2013
Integrated within global NMS
Control, act and support
HEPiX Fall 2013 14
Efficient monitoring and analysis system deployed
Remote operation
Proactive optimization
Efficient end-user support
29/10/2013
Ban them ??
BYOD: The impact
HEPiX Fall 2013 15
802.11n compliant BUT…
1 spatial stream (75Mbps max)Reduced Wi-Fi performance
Ban (very) poor connectivityOptimize RF planningIncrease AP density
29/10/2013
Special deployments
HEPiX Fall 2013 1629/10/2013
Conference rooms
HEPiX Fall 2013 17
• Efficient RF planning for• Minimizing interference• Optimizing load sharing
Capacity is the key concern.
• Reduce Tx Power• Ban slow stations & low data rates• Enable band steering and airtime fairness• Use external antennas
29/10/2013
Underground caverns
HEPiX Fall 2013 18
• Efficient RF planning for• Minimizing co-channel interference• Maximizing coverage
Coverage is the key concern.
• Disable band steering• Enable RTS/CTS• Use external antennas and power dividers• Use a leaky feeder
29/10/2013
eduroam@CERN
HEPiX Fall 2013 1929/10/2013
Travelling?Take Internet access with you!
• A secure international roaming service• Based on a federation of RADIUS servers
HEPiX Fall 2013 20
Home Institute
29/10/2013
How do we deploy it?• freeRADIUS• certificate based for CERN user (EAP-TLS )
• No additional hardware• Fully automated
• Pilot version running• end 2013 : 80% of the infrastructure
HEPiX Fall 2013 2129/10/2013
Conclusion• WLAN at CERN will continue to grow.
• Wi-Fi has became a (highly) popular and fundamental service which requires a significant investment to work properly in a professional environment.
• 802.11ac will bring new opportunities
--- and new challenges.
HEPiX Fall 2013 2229/10/2013
Thank you!
Question
HEPiX Fall 2013 2329/10/2013
Future
HEPiX Fall 2013 2429/10/2013
802.11ac• 5 GHz only• New higher rate modulation • Will be release in 2 “waves”
HEPiX Fall 2013 25
Wave 1 (2013) Wave 2 (2015)
Up to 80MHz Up to 160MHz
Up to 3 spatial streams Up to 4 spatial streams
Single-User MIMO Multi-User MIMO
Up to 650Mbps Up to 1732Mbps
29/10/2013
New opportunities……new challenges
• Higher throughput• Better performance at the same range
• Impact on infrastructure ?• Impact on RF planning ?
• Higher rate only at short range • (-55dBm = same room)
HEPiX Fall 2013 2629/10/2013
