wlan architecture - considerations christoffer jacobsson
TRANSCRIPT
WLAN Architecture - Considerations
Christoffer Jacobsson
What will I talk about?
• Some enterprise WLAN history.
• Explaining the three working planes of a WLAN.
• Centralized architecture, pros and cons.
• Distributed architecture, pros and cons.
• Summary and an extra slide on redundancy.
Where did enterprise WLAN begin?
• Fat/Autonomous APs
• Secondary access method
• Unique solutions for every need
• Limited coverage
• Little or no visibility
• Management nightmare
The three working planes of a WLAN
Data plane Management plane Control plane
• Data Forwarding • Configuration
• Firmware
• Monitoring/Reporting
• Dynamic radio control
• Mobility/Roaming
• Load balancing
• Encryption/Decryption
• QoS tagging
• Data filtering
How do we leverage these working planes?
Data plane
Management plane
Control plane
Data plane
Management plane
Control plane
Data plane
Management plane
Control plane
Data plane
Management plane
Control plane
SSID: Awsome-CompanySecurity: WPA2-PSK
SSID: Awsome-CompanySecurity: WPA2-PSK
SSID: Awsome-CompanySecurity: WPA2-PSK
SSID: Awsome-companySecurity: WPA2-PSK
Wireless Network Management System (WNMS)
SSID: Awsome-CompanySecurity: WPA2-PSK
Centralized architecture – ”The overlay implementation”
YeahBaby Inc. WLAN project.500 employees, 2 devices per person.7 floor building.
Trunk port including new WLAN client WLANs• New VLANs exist only in controller and
Core/Distribution
• Seamless roaming accross all floors
• Centralized channel and power dynamics
• Encryption from client to controller
• One RADIUS client
• One point of management
s
Control
Data
Management
Centralized architecture for a distributed company
NearYou AB WLAN project.20 Offices spread out over the countryAll internet and server access goes through HQ
• New VLANs exist only in HQ
• All APs configured the same way
• Client traffic encrypted to HQ
• One RADIUS client
• One point of management
Control
Data
Management
Drawbacks of a centralized architecture
NearYou AB WLAN project.20 Offices spread out over the countryAll internet and server access goes through HQ
• Dependancy on controllers
• Possible traffic U-turns and bottlenecks
• Scalability issues
• Controllers and licenses are expensive
Control
Data
Management
Distributed architecture – Optimizing traffic flows
UpUpAndAway Inc. WLAN project.4 offices globally.Demands local survivability.
• Client traffic forwarded locally
• Local RADIUS client
• Central management on premises or in the cloud
• Local shared control plane
• Distributed architecture is redundant by design
Data
Management
ControlControl
Data
Data
Control
Distributed architecture – an MSPs perspective
Aranya AB, WLAN as a service.Customers totally separated from eachother.No operational dependencies on Aranya datacenter
Management
Data
Control
Data Data Data
ControlControl
Data
Control
Data Data Data
Drawbacks of a distributed architecture
Management
Data
Control
Data Data Data
Control
• Alot of more wired side management
• More RADIUS clients
• Wireless encryption ends at AP
• Changing architecture can sometimes require hardware replacement.
Extra redundancy considerations
• Who and where are your RADIUS clients and servers?
• Are those server certificates under control?
• Are you querying more than one LDAP server?
• Who and where are your DHCP servers and IP-helpers?
• Always test your redundancy!
