PacketHop unveils first commercial release of WLAN mesh standard

Software stack implements draft version of IEEE 802.11s wireless LAN mesh standard

PacketHop is releasing a software stack implementing the draft version of the IEEE 802.11s wireless-LAN mesh standard. Implemented by chipmakers and equipment makers, different WLAN devices will be able to find each other and form their own wireless infrastructure.

PacketHop this week unveiled the first commercial implementation of the draft IEEE 802.11s wireless-LAN mesh standard.

The Menlo Park, Calif., software vendor is betting that the draft standard is stable enough, and that wireless mesh networks are attractive enough, to draw OEM customers. Once embedded in mobile clients and wireless access points, 802.11s will let these devices discover each other and automatically set up their own wireless infrastructure, using their 802.11 radios. The idea is similar to what Bluetooth devices do today, except over a larger area and with more numerous nodes and clients.

A mesh uses routing algorithms to guide packets through interconnected nodes, dodging around failures and picking an optimal path for packets. Applied to 802.11 WLANs, mesh makes for a more resilient network and eliminates the need to cable every access point to an Ethernet switch.

That's not all, however. A standard mesh protocol in theory will not only let different brands of access points interoperate, but also let any other WLAN-equipped device -- notebooks, high-definition TVs, smartphones, set-top boxes, to name just a few --  join to form an instant wireless infrastructure. The IEEE 802.11s Task Group is expected to ratify the final standard in late 2009, according to Glenn Gottlieb, head of business development for PacketHop.

PacketHop will offer software, a chipset and reference design board. The 802.11s stack is in beta-test, but is available for sampling. The vendor plans commercial shipments in July 2008.

Wireless mesh isn't new, but it's always been proprietary and generally focused on outdoor networks. (Compare wireless mesh products.)

Strix introduced in 2003 an indoor mesh WLAN product line, but changed its focus to products for municipal and other outdoor mesh networks. Other early outdoor mesh vendors included BelAir Networks, Firetide and Tropos Networks, eventually followed by Motorola, Nortel, and finally Cisco. Much of the early rationale for the 802.11s standard has been in terms of extending outdoor WLANs.

PacketHop, too, is shifting gears from its original focus on peer-to-peer client wireless-mesh software, mainly for public-safety and first-responder applications. With that original software, wireless devices, including laptops and handhelds, could find and connect to each other, with packets hopping through multiple nodes to reach a conventional WLAN access point, router, or other gateway. With backing from several venture funds, including U.S. Venture Partners, Mayfield, ComVentures, and GF Private Equity Group, PacketHop originally was a spin-off of SRI International, a nonprofit research and technology-development organization, based in Menlo Park, Calif. In June 2007, SRI acquired PacketHop.

The company now is focusing on being, in effect, an 802.11s systems-software supplier to WLAN chipmakers and access point vendors. PacketHop will be adding some magic of its own to the basic IEEE specification, PacketHop's Gottlieb says. "We have some proprietary enhancements for 11s, but they will be compatible with the standard," he says.

Gottlieb says the standard has several modes, including a client mesh and an infrastructure mesh, which can operate in peer-to-peer fashion, without needing an intermediate access point. "You can unbox your [wireless] devices and they create on their own a communications infrastructure," he says. One or more of the nodes can act as a gateway to an Ethernet LAN, a WAN, or the Internet, for the devices in the 802.11s mesh.

The 802.11s standard introduces new terms for a WLAN. A "mesh point" is any node that supports mesh services. A mesh point that also serves as a conventional access point is dubbed a "mesh access point." And a mesh point that supports a wired connection to a LAN becomes a "mesh portal."

Nodes in an 802.11s network will automatically advertise their profile and mesh capabilities in beacons, and discover and associate with their neighbors. In a sense, a mesh is an extended series of these neighborhood associations, which together work to select the optimal path for forwarding data.

One early experimenter with the developing 802.11s standard has been the One Laptop Per Child (OLPC) project, which is working to create a simple, inexpensive, networked notebook that can be built and distributed in the millions to students in developing countries. With 802.11s, these laptops can automatically create their own infrastructure in a village or a cluster of nearby homes, hopping to whatever broadband or Internet connection might be available. In a 2007 experiment in Australia, an OLPC volunteer used the project's mesh to reach just over one mile with a series of wireless hops.

The 802.11s mesh standard will use the WLAN security features in the 802.11i standard, but is adding some extensions of its own, to ensure end-to-end data security over multiple radio hops. Other features will address how mesh nodes authenticate themselves to each other. The OLPC Web site has a section devoted to some of the mesh security issues, which may be resolved with the final IEEE standard.

Learn more about this topic

802.11s extends wireless outdoors

Network World's Wireless Alert Newsletter: The pending infiltration of Wi-Fi mesh

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Copyright © 2008 IDG Communications, Inc.

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