Service providers around the world are moving swiftly toward triple-play service delivery as the core strategy to increase competitive differentiation, expand revenue and gain new market share. One such goal is to provide innovative and user-centric IPTV and streaming multimedia services combined with VoIP and Internet access as a convenient one-stop shopping experience for end users.
However, delivering triple play is not only a transformation in the way services are bundled and offered, but also poses a new set of requirements that drive a network transformation process from today’s IP service delivery networks built for high-speed Internet (HSI) services to a converged triple-play service delivery infrastructure able to support stringent QoS requirements combined with highly reliable, scalable, nonstop video service delivery in a cost-optimized way. The expected outcome for end users must be a “synergetic” service experience when buying a bundled service rather than a combination of unbundled, nonintegrated services from various service providers.
Evolution to Converged Triple-Play Service Delivery 
To realize the full revenue potential of triple-play service delivery, incremental cost and service convergence synergies can be created by delivering these triple-play service bundles over a shared network infrastructure. This is a radical departure from service dedicated legacy infrastructures in which technological, administrative and operational boundaries can be large hurdles in reaching the objective of integrated service delivery. These barriers can be overcome by the operational convergence on a common triple-play subscriber services management platform to maximize economies of scale, skill and scope and delivering triple-play service bundles as a one-stop shopping experience. Subscriber self-management is a further step to drive down customer care costs, while giving end users the ability to customize service bundles and create a personalized multimedia broadband experience.
Beginning the Transformation
In transforming their networks, service providers typically will deploy a cap-and-grow strategy in which a next-generation IP infrastructure optimized for triple-play service delivery (TPSDA for short) is deployed in overlay to existing best-effort IP infrastructures used for legacy HSI services. New triple-play subscribers and existing HSI customers upgrading to triple play are connected to the TPSDA to enable the higher access bandwidth required for IPTV while reaping the benefits of its cost and performance optimized feature set for supporting triple-play service bundling.
Leveraging Cost Synergies of Converged Triple Play
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The figure above illustrates how an IPTV/triple-play introduction strategy combined with an effective legacy service migration strategy will help service providers to manage capital and operational expenditures (capex and opex) during the network transformation process. It enables absorbing initial ramp-up costs of introducing a triple-play service delivery infrastructure while addressing IPTV and triple-play requirements with incremental cost savings for legacy services and infrastructure.
The transformation process has the following phases:
- Introduction phase The initial roll-out phase of TPSDA, to build IPTV/triple-play service coverage in a given geographical area, in conjunction with legacy voice and HSI networks.
- Upgrade phase This is a cap-and-grow phase in which both new subscribers and existing voice and HSI subscribers can be upgraded to triple-play service bundles delivered by TPSDA. This is indicated by the vertical arrows dropping down in the chart above.
- Migration phase Legacy infrastructure is being phased out to reduce the cost of maintaining separate legacy infrastructures in parallel. This is done by migrating remaining customers to TPSDA as indicated by the horizontal arrows.
The end result is converged triple-play service delivery over a common infrastructure. These phases may overlap in time, especially on a network-wide basis.
The figure below gives an example on how legacy HSI and converged triple-play service delivery can occur:
- The upper layer depicts on light gray fields a legacy HSI service delivery infrastructure, typically deploying ATM DSLAMs, ATM-based aggregation and a PPPoE BRAS providing wholesale Internet access services.
- The bottom layer depicts a triple-play service delivery infrastructure on light blue fields containing BSAN, BSA and BSR connecting into service network back ends.
- At the right, the triple-play subscriber services management system (Triple Play SSC) is depicted on a light blue field. It has the ability to both support DHCP and RADIUS-based authentication, authorization and accounting functions to address subscriber management for emerging IPoE infrastructures (triple play) in addition to existing PPPoE/RADIUS environments.
Triple Play Subscriber Services Control and Legacy HSI Migration
While IPTV and VoIP are using an IPoE/DHCP mode of operation for the HSI service as part of the triple-play bundle, there are typically two deployment scenarios that may apply:
- HSI as a bundled retail service also based on IPoE/DHCP (this is labeled as “1. IPoE/DHCP”).
- HSI as an unbundled service delivered through an ISP partner retaining PPPoE. HSI traffic is forwarded by the BSR to the existing BRAS (this is labeled as “2. PPPoE”).
Scenario 1 results in a common operational model for all services and is the quickest cap-and-grow scenario for legacy equipment. When a legacy HSI subscriber wishes to purchase a triple-play service bundle, he or she is migrated effectively to TPSDA and becomes a triple-play customer.
Scenario 2 minimizes the impact on the existing RADIUS AAA infrastructure and demarcation points with ISP partners. By means of RADIUS snooping in a proxy server mode (blue circle on the right), the Triple Play SSC can account for legacy HSI services within a triple- play bill. Although DHCP-based wholesale technically is possible, it is not commonly used by DSL-based service providers today.
Unified Triple-Play Subscriber Management
The Triple Play SSC plays a key role in enabling the transformation from legacy infrastructures and services to a converged mode of operation for triple play in a nondisruptive and cost-effective way. By supporting authentication protocols for both legacy and converged IP access and aggregation infrastructures, it can control all services a specific customer has subscribed to by means of a common user profile. This makes the fact that individual services may use different types of access policies transparent to the end user, while supporting an easier way to administrate and troubleshoot subscriber services for the service provider.
Unified Subscriber Profile
The application benefits of a converged AAA and policy control solution to manage subscribers and services includes a reduced cost and control complexity, paired with increased control flexibility:
- Introduce new broadband access, aggregation and edge technologies to support converged triple-play service delivery with one-stop shopping and an integrated bill
- Ability to migrate and consolidate legacy HSI infrastructure and subscribers in a common, converged AAA control infrastructure with minimal service impact
- Single sign-on and centralized administration point for subscriber accounts and device profiles for the whole range of triple-play services and access devices
- Integrated control point for subscriber activation and customer self-care with real-time service control orchestration for on-demand services with fast and simple troubleshooting
Arnold Jansen is the product and solution marketing manager for Alcatel. He can be reached at Arnold.Jansen@alcatel.com.
Alcatel www.alcatel.com
