A new way to process VoIP delivers simultaneous voice and data on ADSL–up to 28 calls. Sites can be linked to provide secure private networks. And broadband access is available on high-speed (300 km/h or 190 mph) trains. Access is enabled by a combination of satellite and 2.5/3G services.

Voice calls are symmetric; ADSL isn’t. The slower upload speed–typically 256 kbps–limits the number of simultaneous calls. And when voice and data share the same link, quality of service (QoS) mechanisms are needed. Unfortunately, standard techniques don’t work well at low speeds, and voice traffic can be delayed because it has to wait for a free slot.

The problem is compounded by the fact that these QoS techniques consume around 70 percent of the available bandwidth, which means that three calls is the absolute maximum on a standard broadband link. Add data, and call quality suffers.

Voipex (www.voip-x.co.uk), a UK company, has developed a technology known as ViBE (voice over IP broadband enhancement) that addresses these issues. ViBE treats voice as a data stream that has specific requirements, not only in terms of priority, but also in terms of spacing between packets. And QoS is implemented in a way that is better suited to slower links.

In addition, the bandwidth budget requirement is reduced to that of the compression format. This means that a G.729 call really does only use 8 kbps over ADSL. Because of the way traffic is normally packaged for transmission over a broadband network, each call requires at least 42 kbps.

As a result, instead of a maximum of three calls, 28 calls are now possible on a single broadband line, and voice and data can coexist. Data transfer rates are not compromised by the voice traffic. And data can be given their own share of available bandwidth in a more granular way than with traditional QoS mechanisms.

SP and Enterprise Deployments
Service provider deployments comprise a network server and a small, diskless PC on the customer’s premises. The CPE sits between the DSL router and the LAN switch. It captures all traffic and reduces the payload by stripping out the repetitive inherent transport. This process gets a G729a call down to 8.1 kbps from its original 29.6 kbps on Ethernet or 42.4 kbps on ADSL.

The server platform (or multiple platforms if resilience is required) is deployed to rebuild the traffic and deliver it to its destination. This may be another ViBE link as part of a private network or an IP telephony provider.

In a point-to-point enterprise scenario, a larger CPE device is installed at each location. This enables support for up to 100 concurrent calls (G729a) on a 2 Mbps circuit while still supporting data. Smaller devices are available for link speeds of 256 kbps, 512 kbps, or 1 Mbps. For multi-site networks, a larger server device can be installed at the central site.

Voipex has indicated that future development of the technology will allow multiple links to be used as a single large bandwidth connection.

Broadband at 300 km per Hour
Thalys, the European high-speed train operator, has selected a consortium that will provide wireless broadband Internet access to passengers traveling between Paris, Brussels, Amsterdam, and Cologne by 2008.

The consortium comprises Nokia Siemens Networks; 21Net, the European supplier of broadband Internet satellite connectivity; and the Belgian broadband cable operator Telenet. This represents a combination of satellite, 2.5G, and 3G technologies. Passengers experience data rates similar to static WiFi hotspots while traveling at 300 km/h (190 mph). This will be the world’s first international railway company to offer such services.

A Record Speed: 120 Mbps over Cable
Cisco and UPC Broadband (www.lgi. com/upc_broadband.html) have set a new broadband speed record over cable of 120 Mbps. This data rate was realized over UPC’s cable network in Amsterdam.

The trial also represents Europe’s first deployment of–advance apology for the acronyms–EuroDOCSIS 3.0 (data over cable service interface specifications) and M-CMTS (modular cable modem termination system) technology in an existing cable network. The channel bonding solution in the field trial includes Cisco uBR10012 CMTS and Scientific Atlanta channel bonding cable modems.

The M-CMTS architecture is defined by CableLabs and used with the DOCSIS 3.0 standard. It looks as if it will become a powerful solution for next-generation broadband services. Speeds up to 200 Mbps and beyond are now within reach. V

Bob Emmerson, our European Editor, coauthored with Jeff Pulver the book, Run Your Organization in Real Time. He can be reached at bemmerson@vonmag.com.