Virtual Wi-Fi

Meru Networks has announced "virtual ports" for its wireless networks - a development it claims will finally enable Wi-Fi to replace Ethernet by making it as reliable as a switched Ethernet port.

The new fast version of Wi-Fi, 802.11n, can match the performance of Ethernet, but it can still be unpredictable, said Meru's vice president of marketing, Rachna Ahlawat. Virtual ports, introduced to the latest software on Meru's wireless controllers, give each user a dedicated network service, which can be tied to quality of service and delivered data rates.

Laptops and phones connecting to a Meru network with virtual ports will each see a dedicated BSSID or Wi-Fi Mac address, analogous to a wired switch port, said Ahlawat. This will follow the user throughout the network.

"It's like having a wired network port following you, hopping from radio to radio as you move," said Meru's chief architect, Joe Epstein. "One client can't affect the performance of others," added Ahlawat.

"The approach is very interesting," said analyst Craig Mathias of Farpoint Group, "providing greater control over the relationship between the infrastructure and a given client. I'm looking forward to testing it."

The feature is made possible by Meru's existing virtual cell architecture, said Ahlawat. This "virtualises" the Wi-Fi network, so access points do not all have separate identities: the BSSIDs are centralised, and network resources can be pooled for all users. Virtual ports take this further, by partitioning the pooled resources, to deliver service level agreements to individual clients, said Ahlawat.

Most rival wireless network equipment can also set up multiple BSSIDs, sometimes called "virtual APs," for instance to provide multiple wireless networks for guests and contractors on a site. But they cannot offer virtual ports, because the BSSIDs are held on the individual access points, and not centralised and pooled, Epstein said. "In that situation, attempting to assign a BSSID per client would be wrong - the network would rapidly run out of addresses. Without pooling, virtual ports would be the utter worst case of preprovisioning - not a virtualisation solution."

"Aruba, Cisco and others are trying to find ways to optimise a hublike technology," said Epstein, making a comparison with the old-fashioned hubs that shared access to Ethernet networks until they were replaced by switches which give each client its own port. "They make it work as well as a hub can work, but there will still be a difference between that and a switch-like technology."

Virtual ports can't make capacity out of nothing, acknowledged Epstein: they still share the bandwidth of a limited number of channels. But Ethernet switches are also limited by the uplink bandwidth - and the virtual port puts the two technologies on an equal footing: "The reaction of a switch to load is predictable."

The virtual port was designed for fast Wi-Fi in mind, using the IEEE 802.11n standard, but works on the previous 802.11abg standards, and is already available on Meru's 802.11abg products, said Epstein.