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Ergo have installed Managed Wireless into many schools across the country, and have always been brand agnostic. We’ve installed Cisco, HP and Aruba, depending on client preference, budget or suitability. Over the past 4 or 5 months, we’ve begun to lead with Meru.

We first encountered Meru through the usual channel – a sales call (yes, we get them too) that attempted to explain their USPs and win us over as a reseller. That was over a year ago, and at the time our Lead Solutions Architect thought it sounded either impossible, or at least too good to be true. 6 months down the line, following a glowing recommendation from a school, he took a second look.

Their amazing demo (a real head-on-the-block show) offered a controller and 1 AP with a single radio on 802.11n (2.4GHz) logging on 30 Netbooks simultaneously with a 4MB mandatory profile in 1min and 20secs. VoIP and multi-cast video topped off the show, and really caught our interest. Having seen the demo 4 times now, I’m starting to get a bit blasé about it, but what I witnessed yesterday (April 8th, 2010) has blown any doubts or misgivings that may have been lingering clear out to sea.

The Challenge

The plan was to have a straight-forward race between a Cisco AP and a Meru AP at a secondary school in the North East. 1 trolley-full of laptops all logging on with a much larger profile (50MB) in a classroom environment. Unfortunately a mislaid password meant that we couldn’t get on to the Cisco controller to turn off the other APs in the area – “Stuff it…” I said, “…let’s do it anyway.”

The kit list was as follows:

Cisco:

• 1 x Cisco AIR-LAP1131AG-E-K9 AP (in the room – operating on 802.11g at 2.4GHz)
• 4 x Cisco AIR-LAP1131AG-E-K9 APs (offering bandwidth between 2 and 36Mbps at idle to that room from other areas on g at 2.4GHz)
• 1 x Cisco 4400 Controller

Meru:

• 1 x Meru AP320 (one radio set to 802.11n in 5GHz spectrum, and one set to g at 2.4GHz)
• 1 x Meru MC1500 controller (entry-level model)

The Results

19 laptops logged into the Cisco system in 195 seconds (not bad).

18 laptops logged into the single Meru radio in 154 seconds as the battery died on 1 just as it was about to log-on (amazing).

In essence, a single radio on a Meru AP beat a Cisco managed system with 5 visible APs by over 20%.

The Reason?

Meru implements a patented technology called Air Traffic Control. This means the network controls contention for access to the air. With other Wi-Fi technologies contention is managed using a “collision mechanism” (CSMA/CA) whereby the devices “talk” if no one else is talking.  If another device decides to talk at the same time a “collision” is declared and both devices “back off” and have to retransmit the lost data.

As you get more devices competing for the air you find that you get more collisions, more retransmissions, and the whole system becomes more inefficient.

With large numbers of devices (5 is considered large) the collision mechanism may be 5% efficient! Central management of contention via air traffic control remains nearly 100% efficient.

In our multiple Cisco AP trial, this would have led to collision after collision on the Cisco system. The Meru system tells each client when to transmit, allocating an equal time period to all clients, and reserving an equal amount of uplink time for the AP to the controller, offering stable peak aggregate throughput and minimal loss through contention.

Summary

As I write this, I know that many will simply not believe these results. For one AP to function more efficiently than a managed system of 5 seems ridiculous (even more so against the global market leader), but I really don’t know what else I can tell you. It’s true! Had Meru Networks made this claim themselves I’d have laughed them out of the room, but this trial was arranged by us (we’ll continue to remain brand agnostic to retain the ability to satisfy customer requirements) and monitored by the school’s Network Manager (a Cisco fan). Given that Meru is a single-channel system operating all APs at full power, which means up to 30% fewer APs per site, the cost benefits are similarly impressive.

Gary Hardy (garyh@ergo.co.uk)