How does Cisco's Draft N AP measure up?

Three months ago, Cisco was telling enterprises to wait for 802.11n. Now it has launched an access point that meets the draft fast Wi-Fi standard. What happened to change its mind - and how serious is Cisco's 802.11n AP?

Cisco is doing this because of demand. Spokespeople on the launch webcast repeatedly said 802.11n had taken off surprisingly quickly, and Intel's Randy Nickel underlined the availability of dual-band Draft-N laptops that operate in both 2.4GHz and 5GHz bands: users will have Draft N, so Cisco had better be there.

Cisco must also have feared looking backward compared with other vendors - Trapeze, Meru and Colubris have announced 802.11n access points, and Cisco's biggest Wi-Fi competitor Aruba (despite publicly saying it's too early) has been making noises for some time that imply it's ready to do 802.11n at the opportune moment.

No-one doubted Cisco could do 802.11n. Its Linksys division has been shipping Draft N products since at least April. And even before today's enterprise product was launched, it was certified by the Wi-Fi Alliance, and has been used in the Alliance's test bed to evaluate other Draft 2.0 802.11n products since May.

The standard may change, but the unit is modular and can be field-upgraded to track the standard, so there should be no worries that it might fail to work with 802.11n clients.

Interoperability is not enough, though. Enterprise IT managers may be reluctant to dive into 802.11n, even if their laptops increasingly have the ability to use it: "We view the Wi-Fi Alliance [testing] as a foundation," said Intel's Randy Nickel. Cisco and Intel have been carrying out "real world" tests, which set the new product in genuine enterprise situations, linking to real laptops running real enterptise applications. "We have created a lab that simulates enterprise conditions," said Nickel.

In typical fashion, Cisco used the launch to rehearse all the benefits of the new protocol at great length, telling us it's got more throughput and reliability, apparently unaware that we have heard all that, many times over,

Thin or fat? Both actually

It tended to slide over the architectural questions that are raised by the new standard however.

Trapeze and Colubris have both argued that 802.11n changes things - its throughput is so great that it forces a partial reversal of the centralised wireless switch architecture. Instead of running all wireless traffic through the switch, these vendors have distributed some control back to the AP.

Cisco hasn't done that. Its switches have plenty of bandwidth to handle the new APs, Richard Roberts director of business development told Techworld.

The new APs could be slotted into existing networks one-for-one, promised Cisco marketing vice president Marciej Kranz, implying minimal upgrades to the Cisco's switches. Despite the improved radio performance and range of the new APs, no site survey would be needed, he said, as the existing RF management software should cope. Cisco cited spectrum management Cognio as a partner to help out here.

"Our studies show that the current controllers we provide all have enough throughput," said Roberts. For those using the WiSM module that fits into Cisco's Catalyst switch, upgrades will allow six blades, with a throughput of 48Gbit/s/

But meanwhile, the APs will have a life of their own. Despite rumours of their demise, Cisco is still supporting standalone APs, with huge numbers of fat Aironet access points installed in businesses - many of them dating back to the time before Cisco saw the light and bought a vendor called Airespace with a centralised Wi-Fi switch.

The new WCS includes migration tools for older standalone APs, but there must still be significant demand for fat APs, as Cisco is moving them on into the 802.11n world.

Power to the APs

802.11n APs with two radios for both the 2.4GHz band and the 5GHz band need more electrical power than the 802.11g access points most of us use at the moment. This has led Trapeze to put two Ethernet ports on its APs, to handle more electrical power using the 802.3af PoE standard.

Cisco promises that by the end of the year, its APs will be able to get all the power they need from one Cisco Gigabit switch port - using its own extensions to the IEEE's 802.3af power over Ethernet standard or formal standards if available. "There is headroom in our power delivery to provide more than the 802.3af standard," said Roberts. "That should be delivered by the end of the calendar year,"

"An 802.11n ap with two radio requires a little bit more power," said Ben Gibson, director of mobility solutions marketing at Cisco. "You could add an extra wire - but that's not usually on an IT department's wish list." Full PoE was preferable, he said.

Now for the delugeWith Cisco pushing it, there's no doubt that Aruba and others will follow swiftly. Cisco's 1250 seems a solid offering, and its endorsement of 802.11n for business should boost take-up of the standard considerably.

This story, "How does Cisco's Draft N AP measure up?" was originally published by

Copyright © 2007 IDG Communications, Inc.

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