Aruba Networks Version 3.3 manual Aruba Campus Wlan Physical Architecture

Chapter 4

Campus WLAN Validated

Reference Design

This chapter presents a more complex network model representing a common Aruba deployment in a large campus WLAN environment.

Enterprise networks support thousands of employees, with rigorous service level expectations. To meet these requirements, a reference wired network architecture that defines Core, Distribution and Access elements has become well established among IT network professionals. These elements form the building blocks of large scale, highly-available networks. Vendor validation of their products against this conceptual reference architecture provides IT organizations with assurance that products will perform and interoperate as expected.

Aruba User-Centric Enterprise Wireless Networks also support large numbers of users with stringent service level expectations. To enable IT network architects to successfully plan deployments, Aruba has developed a Validated Reference Design (VRD) that leverages the experience of more than 3,500 customer deployments, peer-review by Aruba engineers, and extensive performance testing. This reference design leverages and extends the familiar wired model in order to deploy a user-centric network as an overlay.

Aruba Campus WLAN Physical Architecture

The Validated Reference Design network model described in this chapter is referenced throughout the remainder of this book. The model depicts a cluster-based architecture typical of large enterprise deployments. For this type of deployment it is a best practice to employ distributed control and data planes using a hierarchical ‘Master/Local’ strategy with separate controller clusters providing each service. This will provide a scalable highly available architecture for data and voice traffic throughout the enterprise.

Some key components of this reference model include:

zMaster Controllers – Two MMC-3600 model appliances configured to use Master redundancy. Each controller has redundant gigabit Ethernet links into the data center distribution switches, and share a Virtual Router Redundancy Protocol (VRRP) address.

zLocal Controllers – Aruba Local Controllers consist of Multiservice Mobility Module blades in an MMC-6000 chassis. In the Aruba VRD, these Mobility Controllers are running in “active-active” redundancy, with two VRRP addresses shared between them. Each controller has two 10 gigabit Ethernet links bonded via Etherchannel to a single distribution layer switch.

zAccess Points – Dual radio (A/B/G) AP65 access points are deployed throughout the enterprise carpeted space, providing high bandwidth access across the 2.4 GHz and 5Ghz bands. These APs are densely deployed. “Dense Deployment” uses a microcell architecture to cover an area using overlapping APs at relatively low transmit power. This design strategy enables ARM to detect and close coverage holes in the event of an AP failure by increasing power on neighboring APs. Smaller cells also help ensure proper load balancing of Voice over WLAN callers.

zSSIDs – There are three Service Set Identifiers present in the Reference Design. One SSID is used for employees and runs WPA2 for authentication and encryption. A second SSID is used by applications such as voice or video, and runs WPA with a Pre-Shared Key for authentication and encryption. The final SSID is open with a web based captive portal for authentication and is used by guests. Each user or device that associates with the network is placed in a role that is enforced by the stateful firewall.

Campus Wireless Networks Validated Reference Design Version 3.3 Design Guide Campus WLAN Validated Reference Design 19