Two new technical reports (TR-058 and TR-059) from The DSL Forum specify the network architecture service providers and equipment manufacturers need in order to deliver next generation digital subscriber line (DSL) services.
‘Forum members have developed these approaches to extend current network capabilities so that existing services can co-exist with QoS dependent services that are increasingly required by businesses and broadband DSL-enabled homes,’ said Michael Brusca, DSL Forum vice president.
The TR-058 document outlines the current DSL architecture. This is followed by a discussion of the set of architectural requirements that are needed to deliver a network that can provide quality of service (QoS) support, bandwidth on demand, multi-casting and real-time service delivery. These capabilities are critical to deliver pay-per-view video services, television type services or voice calls over DSL.
A central element discussed in TR-059 is a new generation of network Gateway Router, today referred to as a broadband remote access server (B-RAS). The B-RAS will not only allow broadband aggregation and basic subscriber management, but will also facilitate dynamic bandwidth management, billing and QoS on a per-customer basis.
TR-059 gives general guidelines for this new class of B-RAS and requires the equipment to fit into existing network architectures, while allowing for interworking with new customer premises equipment (CPE) that supports the traffic management of individual customer sessions, or ‘micro flows.’ This traffic management employs the traffic types defined in the Internet Engineering Task Force (IETF) specifications for DiffServ.
Real time media applications such as voice and video require adequate resources along the transport path, and therefore require specific QoS support. Under the new technical report specifications, a variety of QoS flows can be supported for multiple real time applications over a single DSL connection.
‘Until now, fast data transfer for web surfing, email and file exchange have been the key reasons why millions of subscribers have chosen to upgrade to broadband DSL from a narrowband Internet connection,’ says Brusca. ‘With the implementation of the capabilities specified in TR-059 that build on today’s networks, subscriber upgrades to DSL will be even more compelling.’
The broadband industry is already gearing up to the new specifications, and users should see the effect of these TRs shortly.
The DSL Forum technical reports <a href=’http://www.dslforum.org/aboutdsl/Technical_Reports/TR-058.pdf’> TR-058</a>and <a href=’http://www.dslforum.org/aboutdsl/Technical_Reports/TR-059.pdf’> TR-059</a> are available from the Forum’s website.