Mesh networks, known for their use in city-wide WiFi deployments, are still works-in-development within the IEEE.
In metropolitan areas, when a widespread wireless local area network (WLAN) deployment is an objective, the solution frequently deployed is known as wireless mesh.
The name is indicative of the way in which wireless mesh networks differ from traditional WLANs in that with wireless mesh, the equipment that acts as the node or access point has the ability to communicate with the network’s other nodes-forming a mesh-to determine a signal’s path. That path ultimately leads back to a single, high-speed connection to the Internet. This technology has been a logical choice for cities and towns that want to provide ubiquitous Internet access, and high-profile deployments in Philadelphia, PA and Tempe, AZ have made business headlines.
Tempe’s WAZ Tempe network, as it is called, was completed in February 2006-one month before the Institute of Electrical and Electronics Engineers (IEEE) announced its 802.11 Working Group had selected a single mesh-networking proposal for IEEE 802 wireless LANs. The IEEE called that step a major milestone in the development of IEEE 802.11s Wireless LAN Medium Access Control and Physical Layer Specifications: Extended Services Set Mesh Networking. “Many steps, which will include technical changes, are necessary before this standard becomes final,” the IEEE stated while making the announcement. “But this vote sets the baseline from which the group will work.
Working out specs
”Once completed,” the group continued, “IEEE 802.11s will provide an interoperable and secure wireless distribution system between IEEE 802.11 mesh points. This will reduce backhaul and installation costs. It will also extend mobility to access points in IEEE WLANs, enabling a new class of 802.11 applications that require untethered infrastructure.”
At a November 2006 meeting, the IEEE’s ESS Mesh Networking Task Group commenced a 30-day Working Group letter ballot on Draft 1.0. The group will meet in February to resolve comments generated by the letter ballot.
Tempe and Philadelphia can be deemed early adopters of mesh networking, especially of such wide-scale projects, but the potential benefits of mesh networks have garnered much interest, particularly from users with long distances between nodes. And although the IEEE won’t have finalized 802.11s specifications until next year, wireless mesh networking equipment is readily available for deployment today. In fact, a recent market report from Infonetics Research (www.infonetics.com) stated that for the third quarter of 2006, outdoor mesh equipment sales climbed 38% from 2005’s third quarter, to a total of $121.4 million.
“The range of licensed and unlicensed wireless broadband and mobile technologies now available leads to some interesting opportunities for operators, but also some potentially disruptive challenges to existing business models,” said Infonetics analyst Richard Webb, commenting on research he conducted into not only wireless mesh, but also WiMax, general WLAN, and radio area networks. “All operators are looking at fixed-mobile convergence, but there are now several ways they can get there.”
Infonetics predicts worldwide outdoor wireless mesh access node sales will reach $1.17 billion in 2009, and cites Strix Systems (www.strixsystems.com), Tropos Networks (www.tropos.com), and BelAir Networks (www.belairnetworks.com) as market-share leaders, in that order, for Q3 2006.
That recent report supports the conclusions in a long-term forecast formulated by ABI Research (www.abiresearch.com) a little more than a year ago. When announcing the report, Wireless Mesh Networking: Technologies and Deployment Strategies for Metropolitan and Campus Networks, ABI senior analyst of wireless connectivity Sam Lucero commented, “I think the growth rate will be dramatic. It is an interesting market that has a lot of potential for alternative service providers, such as Earthlink-ISPs who don’t have their own facilities at present. It is an essential means for them to remain viable in the provision of services. Wireless mesh networking allows them a relatively cost-effective way to deploy their own facilities within targeted areas.”
As the IEEE indicated in its March 2006 statement, several steps must be taken before a finalized 802.11s standard emerges, and technical changes are inevitable. In mesh networks, subscribers generally access information via the 802.11b/g protocols. A study conducted by researchers at RWTH Aachen University in Germany examined the possible interference of 802.11b/g systems with another of the IEEE’s wireless communications protocols, 802.15.4, which also operates in the 2.4-GHz band and is used primarily in wireless sensor networks. Marina Petrova, Janne Riihijarvi, Petri Mahonen, and Saverio Labella, who conducted the research, noted that, “802.15.4 and IEEE 802.11b/g are envisioned to support complementary applications and therefore it is very likely that they will be collocated. Since both types of devices operate in the 2.4-GHz frequency band, it is of great importance to understand and evaluate the coexistence issues and limitations of the two technologies.”
Among these researchers’ conclusions was that, “The 802.15.4 operation has practically no negative influence on the concurrent IEEE 802.11 communication; however, if no care is taken about operational channels of the two technologies, the IEEE 802.11 will have a negative effect on the performance of the IEEE 802.15.4 transmission.” They stated that there should be at least a 7-MHz offset between the operational frequencies for satisfactory 802.15.4 performance.
Any 802.11b/g equipment-not just mesh gear-could potentially interfere with 802.15.4, according to these researchers. So, any technical changes required as a result of these findings and future testing would apply across the board to 802.11b/g transmission equipment.
Despite the pre-standard status and potential technical hurdles that must be overcome before standardization is final, mesh vendors are replete with success stories about the deployment of their equipment in municipal and commercial areas. Strix Systems can point to Rochelle Municipal Utilities (RMU) of Rochelle, IL, which deployed the vendor’s system to provide broadband Internet access to business and residential customers. RMU, which was Rochelle’s incumbent provider for years, faced competition from larger providers that could offer DSL and cable-modem services. Wireless mesh was their answer. “Our municipal wireless mesh network puts us at the cutting edge of the technology marketplace. It’s an amenity for the town, and we expect it will attract business,” noted Ryan Alderks, RMU communications superintendent.
Meanwhile, Tropos displays on its Web site a case study from the city of Chaska, MN and its city-owned Internet Service Provider, chaska.net. The ISP started as a means of supplying schools in the community with services they were not receiving from communications providers, and now offers broadband Internet service to all residents.
And BelAir Networks points to the site of this year’s Super Bowl-Dolphin Stadium in Miami-as one of its latest mesh wins. The mesh system accommodates point-of-sale services. “It would have required more than 100 traditional access points to provide the coverage we’re getting in five BelAir nodes,” commented Tery Howard, director of information technology with Miami Dolphins Ltd. and Dolphin Stadium.
And wireless-mesh startup Firetide (www.firetide.com) has boasted some successes lately as well, including a deal with the city of Haverhill, MA under which a mesh system supports IP-based video monitoring for the police department. Firetide teamed up with IP-camera provider Axis Communications (www.axis.com) in the deal. “We are really pleased with how quickly and easily the whole system went up,” said Haverhill police chief Alan DeNaro. “We’re already seeing results and, with this system, we can also record evidence for the police department. With budget cuts and reduced manpower, it’s another set of eyes. And anytime you can have more eyes out there, it helps.”
With technical details to finalize and unserved markets to conquer, wireless mesh networking appears poised to make noise in the communications industry for some time to come.
PATRICK McLAUGHLIN is chief editor of Cabling Installation & Maintenance.