It seemed to be an obvious recipe: take two popular emerging technologies--voice over IP and wireless local area networks--and stir vigorously. But the end result isn't to everyone's taste.

Wireless voice over IP (VoIP) "is very much an emerging market," says Ross Chiswell, CEO of Integrity Data Systems. "As the wireless LAN market grows in Australia, so will this opportunity."

The advantages of wireless VoIP telephony (sometimes called voice over wireless LAN or VoWLAN) are that it can take advantage of existing infrastructure, it is cheaper than DECT (digital enhanced cordless telecommunications, a standard for digital cordless phones), and avoids mobile phone charges when calling other people on or off-site, says Ray Wakim, solutions manager--convergence at Avaya.

Markets
Not everyone is bullish about the technology, at least not in the short term. "I'd question if there is a market yet," says Bjarne Munch, META Group's senior research analyst, global networking strategies. "It's still early days."

META predicts there will be no mass market for VoIP until 2005, and "that limits the market in VoIP over WiFi." The main problem is the absence of standards, he says. While VoIP standards should be ratified by the first quarter of 2004, anything purchased now is based on proprietary standards and therefore limited to niche functions. Similarly, security standards have not been settled, so users must either take a proprietary route or do without security features, he says.

"Our customers are finding it hard to mount a business case for VoIP...or WiFi," says Munch, suggesting corporate trials of wireless VoIP are limited to small installations such as branch offices.

But vendors are reporting successful implementations in the various markets they are targeting for wireless VoIP. The technology is especially suited to hospitals, says Wakim, as staff are highly mobile yet need to remain in contact, and because the frequency used by 802.11b does not interfere with medical equipment or heart pacemakers.

Manufacturing, warehousing, and retail are other functions where contactability is important for employees. For example, car sales staff can be contacted on a single number whether they are in the showroom or out in the yard. There are also safety considerations: Avaya's handset can be mounted on a belt clip, in which case it generates an alert if it remains horizontal and inactive for a certain period in case the wearer has been incapacitated in a fall or other accident and is out of other workers' sight.

Chris Luxford, director of portfolio management for VoIP at Nortel, highlights the same markets as Wakim, pointing out that Symbol's handset that incorporates a barcode reader and local SMS capability is especially suitable for manufacturing and warehousing deployment.

Damian Stock, who handles business development for wireless products at Symbol, claims the company has offered a wireless VoIP phone for around five years. "We've had a long history of doing VoIP over wireless," he says.

Combining wireless data and voice on a single network reduces infrastructure costs and provides opportunities to combine voice and data in one application, Stock says. For example, workers equipped with wireless devices with integrated scanners and VoIP capability have walkie-talkie style contact with their colleagues, can receive outside calls and answer questions about stock levels and pricing (perhaps finding the nearest store that does have a particular item in stock), or--with the addition of a location system--be efficiently directed to pick goods for dispatch, scanning them as they are loaded onto a pallet to create the packing list.

In hospitals, providing patients with a PIN-protected wireless VoIP handset for the duration of their stay means no line changes are needed even if they are moved to different beds. Nurses can be equipped with a wireless device that combines the nurse call system, barcode scanning to confirm patients are being given the right medication, and a phone.

Features such as SpectraLink's Open Application Interface allow the integration of third-party messaging systems with wireless VoIP, says Mark Ablett, managing director, Asia-Pacific at SpectraLink. For example, a nurse call system can be linked to phones and pagers, and in manufacturing, alerts generated by computer-controlled machine tools can be routed directly to the appropriate supervisor's handset instead of being manually relayed to the right person.

Chiswell agrees about the suitability of wireless VoIP for hospitals, but also sees other organisations deploying handsets to key personnel such as IT support staff, senior administrators, and certain partners in accounting and law firms.

It is also very good for temporary installations such as project offices that will be in place for a year or two, for example during a major court case, but he doubts many people yet realise wireless VoIP's suitability for this purpose.

Munch thinks most companies will wait for standardisation, but SMEs may be first out of the blocks as they will take a risk with pre-standards products if they can see a financial advantage. It's too early to predict which specific market segments will take up wireless VoIP, he says.

Capacity, interaction with data WLAN
The same principles of capacity planning that apply to WLANs also apply to wireless VoIP, says Wakim, such as the limits on the number of users per access point. "There is a considerable amount of work that needs to be done before deploying it."

"Current WLANs are not very well designed for voice traffic," says Claus Winhard, business development manager, voice international, 3Com. "The slowest device on a WLAN access point slows down the entire traffic. Voice traffic often breaks up, devices get disconnected, and data connections are slowed down heavily."

If a WLAN is already installed, it is very likely that additional access points will be required. Chiswell points out that there is a limit of around seven active handsets per access point with 802.11b, "but you're not going to give a handset to everyone in the organisation." Munch suggests a more realistic limit is four or five connections before quality suffers, but 802.11e (which adds quality of service features) will improve throughput once it is finalised and incorporated into products. The greater bandwidth of 802.11g will increase the number of handsets per access point. "Standards are slowly getting there," says Munch.

“Our customers are finding it hard to mount a business case for VoIP . . . or WiFi.”

Tools are available to help identify problems. For example, "Sniffer has a generic approach to problems with networks," says Network Associates' Asia-Pacific marketing director Allan Bell, although Sniffer Voice specifically caters for wireless VoIP.

Sniffer's "expert analysis" feature understands protocols and applications, says systems engineer Phil Coates, which lets you see how the network is set up, including an inventory of access points and if they are authorised. Sniffer can look at the different layers of an application, quantify what's happening, and then link that data to show how the network is performing.

Sniffer can examine the wireless infrastructure, for example reporting on interference, inability to connect to access points, retransmissions, encryption settings, and channels used.

According to Coates, issues of particular relevance to VoIP are end-to-end delay (excessive delay leads to people talking over each other, as happens with a call routed via satellite), jitter (variability in delay between packets--voice decoders need to be fed data at a steady rate), and out-of-sequence errors, packet losses, and contention (all of which can cause the sound to break up). "You need to know why [the network] has failed so you know what you need to fix," says Bell.

"As soon as the proposed standard for quality of service in WLANs (802.11e) is approved we believe we will see an increased offer of QoS-enabled WLAN equipment that is suitable for carrying voice traffic," Winhard adds.

Since voice is a real-time application, quality of service (QoS) control is essential yet may be unsupported by low-end access points, says Wakim. Enterprise-grade devices are unlikely to have this shortcoming, he adds.

Chiswell explains there are three design factors that affect the suitability of wireless points for VoIP:

1. the processor used determines the speed of converting wireless packets to Ethernet;
2. the memory size affects the amount of buffering that can be done; and
3. the ROM size affects the intelligence of the device in terms of its ability to perform quality of service tagging and other functions.

According to Chiswell, SpectraLink works with major access point vendors to ensure their products can correctly tag VoIP traffic, and with Cisco and other VoIP gateway manufacturers. A gateway links VoIP traffic with a normal PABX and hence the public switched telephone network (PSTN). Wireless VoIP installations normally also include a device to prioritise voice traffic, such as SpectraLink's NetLink SVP Server. That product also handles hand-offs between access points as a user moves around.

Another problem is that inexpensive access points do not have enough processing power or memory to handle the data packets quickly enough under load, Chiswell explains. Many buyers do not realise the internal differences between access points, he claims: "it's a bit like buying a notebook based on screen size."

Reliability is an important consideration. According to Chiswell, voice network engineers work on the basis of 99.999 percent availability, but 99 percent is typically considered acceptable for LANs. While PC users might not notice a half-second network dropout every minute, someone speaking on a phone certainly would.

"There's nothing like talking to your customers," says Luxford: voice calls are the most critical business application, so it is important to deliver the same quality with wireless VoIP as a conventional phone.

"Take-up [of wireless VoIP] hasn't been as extensive as it should have been," says Stock. Australian companies have instead tended to buy DECT wireless phones from their PABX suppliers and data WLANs from other vendors. This doubles the amount of wiring and other infrastructure, and so increases costs.

While some DECT phones deliver most of the PABX functionality, that's not always the case with wireless VoIP, he says, although soft phones running on notebooks, Pocket PCs, or other handheld devices are generally better than earlier wireless VoIP handsets in this regard.

"A lot of companies have legacy DECT solutions that they've had for several years," says Ablett, and are now looking for a converged approach. Moving wireless voice traffic from DECT to an existing WLAN saves money by reducing the maintenance and management effort. "In some cases you'll need to put in additional access points, but it's not something that happens all the time," he says.

Interoperability
Compatibility between wireless infrastructure and VoIP equipment isn't the only issue. What about the compatibility of wireless VoIP products from different vendors?

According to Wakim, the absence of standardised quality of service mechanisms means you need to buy all the handsets and the QoS server from the same manufacturer. He expects standardisation to occur in a year or two, but notes "it hasn't really happened with fixed IP handsets yet."

But as Ablett points out, if the specific requirements of different users within the organisation call for handsets from different vendors, there's nothing to stop you installing a QoS server from each company. "802.11e needs to be ratified--once it is, there's no need for a QoS server on your network," he says.

Luxford is also more optimistic, predicting that handset manufacturers will provide broad support for SIP (Session Initiation Protocol, a signalling protocol for Internet conferencing, telephony, presence, events notification, and instant messaging) in 12 to 18 months. Phone switch companies such as Nortel have only recently begun supporting SIP, and now the manufacturers of handsets and related devices will soon ramp up their support.

Analog phones are fully interoperable, but digital phones generally can't use of their advanced features unless used in a homogenous environment, he says. VoIP has the potential for full interoperability while providing even more advanced features, although this presents an "interesting challenge" for vendors.

Winhard points out that SIP is not sufficient: "There are some ‘least common denominator' standards such as SIP and H.323 that should provide basic interoperability between different vendors' products," he says. "However, in reality each vendor needs to add certain telephony services that are not specified in the above standards by implementing proprietary protocols, so that typically a phone from one vendor cannot be used on the LAN telephony system of another." This applies to wired and wireless VoIP handsets.

Motorola, Avaya, and Proxim have announced they will collaborate on the creation and deployment of converged cellular, WLAN, and IP telephony solutions that will deliver new levels of communications mobility and network connectivity. These will be enabled by an array of new products including a WiFi/cellular dual-system phone from Motorola, SIP-enabled IP Telephony software from Avaya, and voice enabled WLAN infrastructure from Proxim.

Motorola will also create network components to control the hand-off between WLAN and cellular networks, while Proxim will facilitate hand-offs between WLAN access points.

Cost savings
Wakim says it is possible to achieve overall cost reductions with wireless VoIP just by avoiding or reducing calls placed to or from normal mobile handsets. A reduction of 40 to 60 percent in mobile bills can be achieved, he claims: for example, if you are in a meeting room waiting for the last person to arrive, the chances are that you will try to find out where they are by calling their mobile from yours.

Such savings would be particularly achievable when using hybrid GSM/VoIP handsets: when they are in range of a base station, outgoing calls are placed through the PABX at fixed line rates rather than the (normally) more expensive mobile tariffs, yet giving users the convenience of a single handset.

"The biggest driver is cost reduction," says Wakim, but there is some possibility of running applications on wireless VoIP handsets and that could provide new business opportunities. "The boundaries are starting to be pushed," he says.

"I don't think there's going to be a huge uptake just because it's wireless IP," says Wakim. "It's not going to be for everybody."

"[Wireless] voice over IP isn't cheap--it needs to be integrated well with the PABX," says Stock. A hybrid solution is needed, using wired or wireless VoIP where it makes sense, and normal phones elsewhere, he suggests. In particular, a normal phone keeps working in the event of a power failure as it is driven from an exchange with substantial battery backup; moving to VoIP means you are responsible for your own backup power arrangements.

Cost reduction isn't only about call charges. Luxford points out that wireless telephony makes good sense in a retail environment to minimise the time taken by a salesperson to deal with a phone inquiry. In a small store, a simple cordless phone might be more appropriate, but it's easy to see how wireless VoIP could be useful in a larger business.

Other phone technologies can be used in conjunction with wireless VoIP such as Nortel's Meridian Integrated Personal Call Director which provides a single number ‘follow me' service, routing calls to any or all of six different phone numbers either simultaneously or in order. Those numbers could cover fixed or wireless VoIP handsets, mobile phones, and fixed lines at home or other locations. A Web-based tool lets individuals control this routing. "People are far more mobile than they have ever been," says Luxford. "Being in contact is very important."

Winhard takes a similar tack, pointing to the productivity advantages of call centre, unified messaging, and other applications deployed on LAN-based systems such as 3Com's NBX.

Whether you are talking about cost saving or revenue generation, the benefits need to be measurable because according to Wakim, "the handsets aren't going to be particularly cheap." He predicts prices in the $800-$1200 range. However, it is quite easy to analyse savings by correlating PABX records and mobile phone bills with the times people were on site. You can then determine which technology is the most appropriate to gain the desired cost savings.

"It's not going to be for the small end--it's for medium to large enterprises," says Wakim, but "it's only a matter of time before the costs are driven down."

Munch predicts that the high volume production of the chips needed for wireless VoIP handsets will eventually give hybrid GSM/wireless VoIP handsets a cost advantage over DECT, but not for another two years or so.

The ability to roam between GSM connections, voice-capable public WiFi hot spots, and a private WLAN during one call would be attractive to--perhaps even expected by--users, but is unlikely to happen, he says.

But Roger Geerts, systems engineering manager for Australia and New Zealand at Juniper Networks says carriers in the region are beginning to experiment with VoIP support at wireless hotspots, "but it's very rudimentary".

As Stock points out, a brief delay when moving between WLAN and GSM while a new connection is established is no problem for data, but it wouldn't be acceptable for voice.

“It’s not going to be for the small end—it’s for medium to large enterprises, but it’s only a matter of time before the costs are driven down.”

Although carrier-provided wireless VoIP would appear to duplicate the existing GSM and CDMA networks, Geerts says it could prove cheaper to provide voice service at some difficult locations using wireless VoIP than cellular telephony.

According to Luxford, Nortel expects wireless LANs to dominate deployments over a five to 10 year period. Coupled with the general growth in the adoption of VoIP, this suggests wireless VoIP will become more popular.

"In a long-term perspective, WLAN VoIP will replace existing cordless technologies such as 900 MHz DSS or DECT," says Winhard

Security
"Security is definitely key," says Wakim. Avaya's forthcoming hybrid GSM/wireless VoIP handset--due in Australia late 2003 or early 2004--will encrypt data prior to transmission and may use VPN technology, he says.

3Com takes a similar approach, using "a basic scrambling of voice packets to make it harder to eavesdrop on a conversation," says Winhard, and VPNs can be used to encrypt the entire data stream.

Chiswell says it's not normally possible to use traditional approaches such as VLAN, IPSec or 802.1x in a mobile wireless environment. For example, a VLAN connection can't usually be maintained when moving between subnets. This problem is solved by Bluesocket's wireless gateways, he says, which support IPSec and PPTP encrypted tunnelling, provide secure access to users moving around a WLAN, and offer bandwidth reservation for voice traffic or other classes of service.

If you are looking at security from the perspective of preventing access by unauthorised devices, another possibility is to take advantage of access points that can impose access controls based on MAC addresses (so "foreign" devices cannot connect), he suggests.

Security also involves protecting VoIP installations from denial of service attacks and MSBlast-style issues, says Luxford. "We don't run Windows operating systems on our core switching systems," he adds.

Executive summary
Wireless VoIP is a combination of two technologies: wireless LAN and voice over IP.

• Standards for wireless VoIP such as SIP (session initiation protocol) are emerging, and full interoperability is expected within a year or two. At present, the compatibility of different vendors’ handsets, access points, and gateways is variable, so check before buying a heterogenous system. Even then, some handsets may not provide access to every feature of a particular PABX.
• Early adopters of wireless VoIP can be found in manufacturing, warehousing, retail, and health—all areas where workers move around the premises yet need to stay in contact.
• Wireless VoIP handsets have a similar form factor to cordless or mobile phones, combined with barcode scanners or other devices, or implemented in software for PCs or handheld devices including Pocket PC.
• Around half a dozen simultaneous wireless VoIP calls will saturate an 802.11b access point, so careful capacity planning and proactive network management is needed to avoid user complaints. Specialised tools may make that job easier for technical staff lacking specific expertise.
• Hybrid wireless VoIP/GSM handsets will soon be available, connecting to the WLAN in range and otherwise automatically switching to the carrier network. Some carriers are conducting trials of wireless VoIP at WLAN hotspots, but automatic roaming between WLAN and GSM while a call is in progress is some way off.
• High levels of on-site mobile phone use can provide an opportunity for substantial cost savings from wireless VoIP. The technology also provides opportunities for productivity improvements, which can be substantial.
• Security is always a consideration when implementing WLAN, and the importance of voice traffic means even more attention is necessary.

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What about bluetooth?

The inclusion of a voice recognition server means calls can be placed by speaking the number required, with a soft dialler running on a PDA or PC as an alternative.

A system serving 30 people through around 10 base stations costs around $30,000 including servers and software licences, says Terry Walsh, vice president, marketing and sales.

Norwood’s customers are drawn from a variety of markets. Healthcare is attracted by the mobility, hands-free operation, and freedom from interference. Financial services (eg private banking, traders), advertising, and public relations require personnel to be accessible by their clients: “it’s about more calls making their mark the first time,” says Walsh. 128-bit over the air encryption and frequency hopping provide security where it’s important, he adds. Government departments are using the technology for occupational health and safety reasons, preferring the ergonomics of headsets to regular handsets.

The Bluetooth network can also be used for data, taking advantage of either the serial port or dialup networking profile in the Bluetooth specifications, says product manager Will Klinger. Despite the name, no dialling would be necessary to access a corporate network from a Bluetooth-equipped notebook or PDA in this way.

EnterpriseMobility has been adopted by Damovo to provide systems that allow appropriately equipped GSM phones on their clients’ premises to place calls via Bluetooth and the PABX rather than the mobile carrier, saving 27 to 40 percent on call costs.

The technology is also being trialled for British Telecommunications’ Project Bluephone initiative. Bluephone is aimed at delivering fixed and mobile calls through a single device, with propositions for office workers, teleworkers, residential, and public hot spot users.

Inmarsat drives world rally championship

The organisers of the World Rally Championship have to cope with many of the IT and communications challenges faced by more conventional businesses. These include the need for real-time, straight-through processing; the flexibility to work in different locations, often in difficult conditions; and the ability to handle large amounts of data.

Two types of data are collected using Inmarsat facilities during WRC events. Split times are captured by trackside equipment at two or three points along each stage. Before Inmarsat became involved in the sport in 2002, split times were not recorded due to the difficulty of relaying them efficiently and reliably from remote areas. Times are also recorded at the end of each stage. Secondly, each car has an onboard computer that uses GPS to log its position five times a second. At the end of each stage, this data is downloaded via an 802.11b WLAN.

Both types of data are transmitted via Inmarsat to the WRC data centre near London. The data are then bounced back to the on-location operations centre for distribution to rally officials, teams, and the media, who have access to the data just three seconds after collection. This back-and-forth structure provides a consistent service platform regardless of where any rally is held.

Inmarsat also provides the WRC community with data links between team headquarters and the crews in the field, phone links to keep personnel in touch with their families, and voice, data, and videophone facilities for the international media.

Each car collects a lot more data than is currently relayed. Images from the onboard video cameras are stored on tapes that are transferred to the editing suite via sneakernet when the cars return to the rally service park. Inmarsat has been testing the use of MPEG video recording, which would allow for wireless transfer at the end of each stage. This would reduce the pressure on the video editors, as each video would be available within seconds of the completion of a stage and editing could start without the current delay while tapes are loaded.

The onboard computers also store information collected by the engine management system and other sensors, and it is important for crews to begin analysing this data as soon as possible. Subaru, for example, stores the data on a PC Card. As soon as the car arrives at the service park, a crew member extracts the card and runs back to the garage while the car completes the formalities.

According to Richard Denny, vice president, global satellite operations at Inmarsat, these logs could be downloaded along with the GPS data at the end of each stage. This would allow crews to make better use of the limited time their cars spend in the service park.

Virtual Spectator
Rallying has some drawbacks as a spectator sport. The special sections are usually well away from population centres, and may require spectators to drive for a couple of hours and then walk several kilometres from parking areas to observation points.

None of this seems to bother the hardcore fans, as 12 million spectators attend the 14 events, and approximately 10 percent of the population of Finland turn out for their country’s leg of the WRC! The biggest limitation on the sport’s attractiveness to the average TV spectator is perhaps that the cars cover the course sequentially, so it is difficult to see how well one is doing relative to the others.

Using techniques originally developed for the America’s Cup in New Zealand and a mix of off-the-shelf and custom software, Virtual Spectator (which recently merged with Pineapplehead’s sports graphics business) recreates portions of the rally from the GPS logs. The video game-style animations can combine the progress of multiple cars to give broadcast viewers a head-to-head comparison. “We try to produce the data the camera can’t see,” says Jack Ralston, Virtual Spectator’s general manager, sales and marketing.

The animations must be released to broadcasters in time for that evening’s news, but work can’t begin until the GPS data from the cars has been received. Transferring the data from the cars at the end of each stage via Inmarsat has accelerated the process, and the company is looking forward to the advent of real-time data acquisition.

Virtual Spectator is exploring the delivery of its animations to the public via broadband services and mobile phones. The company also has its eye on the possibilities provided by transferring a richer set of data as each car finishes a stage, and is experimenting with physiological data (heart rate, etc) from the drivers and co-drivers.

Stephen Withers travelled to Perth as a guest of Inmarsat.

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