Next Generation Broadband DSL Architectures for Triple-play Applications

The Triple-play market, which combines voice, data and video services, requires five major changes in the current Broadband DSL architecture model:

• Home Media Node; this is a smart CPE device able to integrate a multiservice home environment. This will allow 
   them to implement value added services, to get a fast penetration for these services and good margins.

• Ethernet DSLAMs and IMAPs (Integrated Multi-Access Platform); A next generation access is required to offer
  optimized costsand to allow the service providers to implement advanced services. IMAPs are targeted by the 
  incumbent players in their NGN migration for integrating the NB, BB and Voice access in one access device.

• DSL Forum TR-58/59 BRAS compliance; a state of art Broadband Aggregation Remote Server is required to 
  support the advanced triple play services and provide the scalability, functionality and high availability required for
  implementing value added services over the existing ATM access networks as well for integrating Ethernet
  DSLAMs in the future.

• Remote Access to MPLS VPN wholesale model – a next generation wholesale architecture is required to allow the
  Network Services Providers (NSP) to offer advanced services and the Network Access Providers (NAP) to increase
  their wholesale service margins and drive a differentiated wholesale offering

• Subscriber and Service Management and Control; A triple play Broadband service offering is about subscriber self-
  care and service activation, owning the subscriber experience by allowing him to get the service behavior he
  expects anytime and everywhere. This requires a standard based, open and scalable subscriber and service
  control layer.

The common requirement in the new Broadband DSL architecture, which includes the user CPE through the services providers network till the application services providers, is quality of services (QoS) to guarantee voice and video qualities over IP networks.

Currently, the ADSL Forum defines QoS methods to guarantee triple-play services, based on TR-59 DSL Evolution – Architecture requirements for the support of QoS Enabled IP services. The TR-59 consider in its specification, network capabilities and services such as:

Capabilities:
• Bandwidth on demand
• QoS, including QoS on demand
• Many to many access

Services
• Multicast audio and video media applications
• Video on demand applications
• Voice services
• Interactive gaming
• Variable bandwidth

The QOS model described by TR-59 is entirely based on IEFT Diffserv. The overbooking of the access network is essential to ensure economic and network efficiency. However if the infrastructure is to support delay and jitter sensitive applications than the BRAS has to implement hierarchical scheduling capability with the ability to provide back pressure within the system to ensure that congestion is pushed back to the IP class based scheduling system. To control the number of levels of hierarchy in the BRAS, TR-59 recommends that the complexity (the number of ATM switch points) between the BRAS and the end user be kept to a minimum. Policy control and dynamic change of a user’s QoS attributes is essential to ensure efficient use of available bandwidth and to allow the new services to be introduced.

The QoS mechanisms are enabled in different network components, from the user to services providers, according with the interconnect network model. Bellow, there are descriptions of those models:

Subscriber access using PPPoE aggregated into L2TP tunnels delivered to NSPs (Internet services)

Subscriber access using PPPoE or IP over Ethernet into IPVPNs to NSPs (Intranet services)

Subscriber access using PPPoE or IP over Ethernet aggregated into a common, public,
QoS enabled IP network and delivered to Application Service Providers

Bynet allows today Services Providers to offer triple-play services to their end users, offering a variety of solutions including:

Network infrastructure
• Smart router gateways
• IP DSLAMs
• Next Generation of BRAS
• IPVPN / MPLS networks

Applications
• Voice systems
• Video systems
• Content Distribution and Subscriber Management

Professional Services
• Design
• Installation
• Testing
• Maintenance

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