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 planeManagement planeControl 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-Company Security: WPA2-PSK SSID: Awsome-company Security: WPA2-PSK Wireless Network Management System (WNMS) SSID: Awsome-Company Security: 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 country All 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 country All 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 Control 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 Control Data Control Data

Drawbacks of a distributed architecture Management Data Control 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!

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