Specifications

CHAPTER 9
Wireless LANs in a Campus Network
Wireless LAN Controllers
Cisco WLAN controllers can be either an appliance, a module, or integrated into a 3750G switch. In the appliance line,
the 5500 series is meant for large deployments and, as of this writing, supports up to 250 APs. The 4400 series is for
medium-sized deployments and supports from 12 APs to 100 APs. The 2100 series is for small deployments and supports
from 6 APs to 25 APs.
The WLAN controller integrated into a Cisco 3750G switch can support up to 25 APs per switch,or 100 per switch stack.
The Wireless Services Module (WiSM) can be installed into Cisco 6500 and 7600 series switches for large deployments
that need support for up to 300 APs. Cisco ISR routers have a WLAN controller module that can support up to 25 APs for
small deployments.
Hybrid Remote Edge Access Point (H-REAP)
Wireless controllers need not be in the same physical location as their associated APs. However, having an AP and its
controller separated by a WAN link can lead to some inefficiencies and problems. Two clients in the remote location that
need to connect would have their traffic tunneled over the WAN to the controller and back again. Additionally, the AP
would lose functionality if the WAN were down.
H-REAP addresses these problems:
n Connected mode: When the controller is reachable, the AP transmits user authentication to the controller. It sends
traffic in specified WLANs (usually local traffic) to its local switch, however, rather than tunneling it back to the
controller. The connection from the AP to switch needs to be a trunk link if the AP handles multiple VLANs. Traffic
bound to remote networks is still tunneled over the WAN to the controller.
n Disconnected mode: When the controller is not reachable, the AP authenticates clients itself. It still sends client to
its connected switch, but of course remote locations will not be reachable if the WAN is down.
H-REAP is configured at the controller for any APs that operate in this mode.
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CCNP SWITCH 642-813 Quick Reference by Denise Donohue