1 Vidar Stokke Senior Engineer at the Norwegian University of Science and Technology, IT-division, Networking Programme: 1.History of wireless networks at NTNU 2.The wireless network with standalone APs 3.The wireless network with controller based APs 4.Pros and cons of controller based networks Controller based wireless networks

2 History of WLAN at NTNU 2004/2005: 250 autonomous APs (802.11b og g) Hotspot coverage –public areas and meeting rooms –Approx 20% coverage Authentication by web portal (HP) and/or VPN (Cisco) Challenges: –Time consuming administration –No mobility –Capasity issues due to many users on few AP –Web portal did not scale associated clients

3 The Wireless Campus project – with lightweight APs The goal was 100% wireless coverage in NTNUs buildings. Started Q and terminated Q The process: –Site survey (External company) –Wiring and AP mounting (3 different electrical contractors) –PoE-switch installation in wiring cabinets (NTNU IT) Resulted in approx 1400 APs, 18 wireless controllers and 100 PoE switches

4 The Wireless Campus project – with lightweight APs In 2011: –1800 APs –20 controllers – simultaneous clients at peak hours –Approximately sqm coverage Deployment of controller based wireless network was a success

5 A comparison of standalone and lightweight/controller based wireless Standalone –Everything on and through the AP Traditional lightweight –Everything on and through the controller Hybrid lightweight –Almost everything on and through the controller, but with a certain flexibility

6 Wireless with standalone APs

7 Wireless with lightweigh APs

8 Wireless with lightweight APs and H-REAP

9 AP join process - discovery Ways to discover controllers –Layer 2 broadcast on local subnet –List of previously known controllers –OTAP (Over The Air Provisioning) – removed from Ciscos SW –DHCP option 43 –DNS lookup for cisco-capwap-controllers.domain

10 AP join process - CAPWAP

11 Mobility groups Several controllers can join one mobility group Client roaming across different controllers and APs –Without loosing connection –Without the need to reauthenticate

12 Mobility groups

13 Auto-RF Each controller is part of an RF network –APs connected will forward RRM-info to its controller about other APs it sees. –Adjusts channel and power assignment based on leaders computations One controller is the leader of the RF domain –Collects necessary RRM-info from other controllers –Tries to avoid neighbour APs on same channel and interference –Calculates and computes the best possible channel and power assignment for the different APs

14 Rogue detection and containment APs not within the RF-domain is marked as rogue Possible to do a joint effort to take them down –Up to 4 APs join together –Send diassociation messages to the connected clients

15 Downsides with lightweight Get stuck with one brand (ie. Cisco) –Even though CAPWAP opens for third-party components Harder to do hardware upgrades on APs and/or controller –Controller and APs need to support each other Expensive with a low number of APs

16 Benefits of lightweight solution Easier management/configuration of a large number of APs: –All configuration done at controller and pushed to APs Major changes done by the click of a button –Software upgrade done from controllers and deployed to APs –PlugNPlay of new APs and replacement APs Radio Resource Management (RRM) –Auto-RF –Client load balancing

17 Benefits of lightweight solution Better mobility for clients –Due to mobility groups Improved overview of the wireless network –Client information and debugging –AP statistics –AP and client alarms Location based services (requires WCS) –NTNU Campusguiden

18 A demo?

19 Questions?