I Manage a Microcell Network
If you've used wireless, you already know how convenient and liberating it can be. But if you're responsible for building and maintaining networks, you also know how frustrating it can be. With the microcell architecture used by most existing 802.11 networks, freedom for users comes at the expense of headaches for IT. And as wireless access moves from a convenience to a critical business need, problems of radio interference, channel planning and bandwidth contention grow.
Meru is different. From the start, Meru's founders envisaged the All-Wireless Enterprise: a world where wireless is the equal of wired, offering equivalent performance and security Ð and of course, much greater mobility and flexibility. This led them to develop the Virtualized Wireless LAN, an architecture in which controllers manage clients as well as access points, in which the artificial boundaries created by microcells are erased, and in which each client remains connected to a single Virtual Port no matter where in the network they move.
Why Virtualize?
The Virtualized Wireless LAN is not just a software layer that can run on top of existing wireless infrastructure. It represents a fundamentally different way of building wireless networks, one that demands more advanced technology from access points and controllers but less time and expense from the IT department. Virtualization offers the same performance, security and manageability benefits already achieved by server and storage virtualization, benefits that grow as the wireless LAN incorporates 802.11n, affording higher user densities and supporting demanding applications such as voice and video.
Why Not Microcells?
Like 802.11b, the microcell architecture was an important step in wireless LAN evolution, helping wireless grow from isolated islands of connectivity to enterprise-wide coverage. But it cannot scale to a world where people rely on wireless as their main network connection or one where voice, video and data must coexist. As users place greater demands on the network, microcell's problems with radio interference, spectrum consumption and client contention for limited resources can only grow.
| Microcell | WLAN Virtualization | |
| 802.11n | Full coverage at 300 Mbps in 5GHz. only | Full coverage at 300 Mbps in 2.4 GHz. and 5 GHz. |
| Cumbersome channel planning necessary | No channel planning required | |
| Security | Layer 2 and 3 security | Layer 1, 2 and 3 Security: RFBarrier™ and AirFirewall™ protect the physical perimeter |
| Role-based access control | Role-based, application-based and user-based access control | |
| Firewall uses deep packet inspection | Firewall uses deep packet inspection and flow signatures that classify even encrypted traffic | |
| Management | Automated management of access points only | Automated management of access points and clients, using no proprietary client-side extensions or software |
| Adaptive Radio Management: tries to compensate for co-channel interference | Proactive Spectrum Management: load-balances clients across multiple channels | |
| Troubleshooting takes days of trial-and-error trying to recreate exact network conditions | Troubleshooting takes minutes due to automated signature correlation and recording of important events. | |
| Roaming | Client-initiated handoff | Infrastructure-managed handoff |
| High and variable latency roaming | Zero-latency roaming | |
| Performance | Hub-like: All clients contending for random access to the same AP | Switch-like: Each client connects through dedicated Virtual Port |
| Unpredictable: Contention and interference mean wide variations in performance even between clients connected to the same AP | Predictable: Airtime fairness ensures each client gets equal share of network resources | |
| Interference mitigation | APs must be turned down to ~ 60mW to reduce interference, minimizing each’s coverage area | APs can transmit at ~ 100 mW, so 30% fewer are needed than with microcell architecture |
| Co-channel interference: Neighboring access points must use different channels | Air Traffic Control: Neighboring access points can use the same channels | |
| Spectral Efficiency | Each layer of coverage consumes at least three non-overlapping channels | Each layer of coverage consumes only one channel |
| Scalability to denser networks | Limited: Many channels already consumed to provide a single layer of coverage | Linear: Each new radio or access point adds as much capacity as the first |
| Scalability to wider coverage | Limited: Expanding the network increases management complexity as channel plan must be recalculated | Easy: Every AP uses the same channel, so adding each new AP is as easy as adding the first |