In the past, I've given credit to Colubris Networks for being the pioneer in separating out data from the other planes, Siemens has also provided something very similar from day one. Unfortunately, Siemen's wireless product--when it was still the startup Chantry--did not gain significant traction, but the company appears to be doing well in the healthcare market.
Aruba gave Aerohive a bit of a fright last week when the company introduced its "Mobile AP." Aerohive, Interop's Best Startup Product winner, demonstrated in its presentations the benefits of a controller-less architecture, where both the management and the control planes reside. The advantage? No controller--or second controller for redundancy--is required at branch offices or retail stores, thereby reducing capital and implementation costs. But Aruba's Mobile AP software, in conjunction with its mesh software also announced last week, allows a branch office to leverage its centralized controller for management without a controller at the edge. The remote office still retains role-based user access control, a stateful firewall, NAT and split tunneling. Although Aruba won't readily admit it, a lot of its centralized controller's functions have been brought to the edge, and I believe it's a sign of things to come that the company will soften its "centralized-only" stance. A second data point is that its mesh product, also recently announced, will allow for two mesh-attached devices that use encryption to communicate directly with each other rather than traverse over the latency-inducing wireless backhaul to the controller and back again.
Cisco was all about fat APs in its first days with Aironet products and WLSE, but later developed WLSM (Wireless LAN Services Module) for the Catalyst 6500. Not being able to move quickly enough itself, Cisco purchased successful startup Airespace--with its centralized model--and introduced WiSM (Wireless Services Module) and rebranded the controllers. Since that time wireless support has found its way into Cisco's ISR (Integrated Services Router) and its Catalyst 3750G switch. With Cisco's leadership position in the switching market, it's reasonable to speculate that the company may also push some of the data plane into the edge via a software load in high-end edge switches. In addition, Cisco has its H-REAP (Hybrid Remote Edge AP), designed for branch and remote offices. It performs local switching of traffic and some control plane functions.
Meru was somewhat maligned for its slow support of 802.11a, but last month came early out of the gate with announcements on 802.11n and its new 3TDS (3 Tier Traffic Distribution System) architecture. Rather than centralize the three planes at the core, Meru has introduced "Distribution Points" that sit closer to the edge and place the data traffic onto the edge. It's not exactly clear why Meru wants to push the traffic to the edge. Unlike Trapeze, which appeared to need a differentiator and possibly had some centralized controller scaling concerns, Meru's single-channel architecture was unique enough. Some competing vendors speculated that perhaps the compressed timescales of 802.11n signaling would challenge the centralized model. But Meru was adamant that its coordinated and deterministic algorithms are not limited by LAN latencies--even if they were as high as the 20 to 40 msec I threw out. The only consideration left to consider is that the company also had controller scalability concerns. Its latest controller introduction, the MC5000, supports up to 200 APs and has a list price starting at $65 thousand. In our briefing, Meru stated that whether the customer chose a centralized or distributed model, the pricing is approximately the same. Aruba's 6000 has a lower price point--$67 thousand for 512 APs--and its pre-802.11n APs promise to be much cheaper than Meru's.
Trapeze previously offered a centralized WLAN switching model (a la Aruba). But anticipating the traffic rate increases of 802.11n and the demand that would place on its controllers as well as conceding to the benefits of distributed switching, the company introduced "Smart Mobile" a little over six months ago. This implementation of this marketing term essentially imitates what Colubris has done for a long time: placing the data plane on the AP and the management and control plane on the controller. In its marketing pitches I missed the fact that this is not a migration strategy but rather offers customers a choice. In fact, Trapeze's vice president of marketing, David Cohen, confirmed that most of the company's customers continue to centralize their data flows. Traffic can be locally switched by the AP on a per SSID or per VLAN basis. Clients, such as Vo-Fi phones, can be placed into a specific voice VLAN, in which case all traffic might be locally switched for reduced latency. But multi-function clients, such as a PC with a Web browser a VoIP softphone, would have to choose one mode over another and not on a per-application basis. Choice often leads to complexity, and in this case wireless network administrators will need to plan carefully which client traffic they want to manage centrally and which client traffic will switch at the edge.
