Aruba Networks Version 3.3 AP Placement, Power, and Connectivity, Local Controller Placement

least two connections setting up redundant links to two data center distribution switches. With the Active-Standby configuration recommended in this VRD, this yields a full mesh between the two controllers and the distribution switches. The MMC-3600 does not have redundant power supplies; connect each appliance to discrete power sources in the data center.

Data center

Master		File
Mobility	Web
Controller		PBX
Distribution
		RADIUS
switches

arun_051

Local Controller Placement

The Local Controller should be connected to the distribution layer switches in an MDF or similar suitable location with backup power, with each Active-Active pair connecting to separate switches. Using the MMC-6000 Multiservice Mobility Controller as recommended by this VRD, each blade should be connected to its own distribution layer switch with two 10 Gigabit Ethernet connections bonded with Etherchannel. A fully populated MMC-6000 chassis with four blades require eight Gigabit connections. Each MMC-6000 chassis should contain redundant power supplies connected to discrete power sources.

Two 10 gigabit links

Distribution

Local	Distribution layer
Mobility	switch
Controller

AP Placement, Power, and Connectivity

Mobility Controller and Thin AP Communication

Mobility Controllers and thin APs work as a system. Configuration for all APs is automated and centralized on the Mobility Controller. Upon bootup, each AP uses DHCP to obtain its IP information then connects to the Local Controller to retrieve its initial configuration, and to check for firmware updates. Subsequent configuration changes are performed centrally within the Local Controller and pushed to each AP. If the firmware on the AP does not match the controller, the AP will automatically use either FTP or TFTP to upgrade itself to the new firmware stored on the Local Controller with no administrator intervention.

Communication between the AP and the Local Controller at the Aggregation layer occurs using a GRE tunnel established during the boot process. Because the GRE tunnel is in place, all wireless traffic is transmitted directly to the controller, so no special VLANs need to be deployed for APs; they will function over the existing infrastructure as would any other client. This avoids the “VLAN explosion” problem in some other architectures where every user VLAN must terminate on every AP throughout the enterprise. On the other side of the GRE tunnel, the user traffic is then switched to the correct

34 Mobility Controller and Access Point Deployment Campus Wireless Networks Validated Reference Design Version 3.3 Design Guide