• HOME
• COVER STORY
• CASE STUDY
• TECHNOLOGY UPDATE

Delivery of iP-based Multi-Services using the smartEdge Multi-Service Edge Router (Excerpt)

The delivery of IP-based multi-services has become an important business objective for service providers. Expectations have been set at high levels for these services to become the new source of revenue for service providers. Specifically, three applications are targeted immediately: VoIP, IPTV, and broadband Internet. For the service provider the bundled approach in offering these services is essential, as it is seen to be the real killer application. Among these services, IPTV is expected to generate the major share of the revenue.

The infrastructure required to deliver IP-based multi-services are based on two major models: centralized versus distributed. These architectures have been analyzed and detailed studies have been done specifically on the economic differences between the two. The economics have been verified by two independent research groups showing that the centralized architecture provides a much better investment.

Currently, three distinct approaches in designing a Multimedia on Demand (MoD) network architecture have been used by different service providers as they are shown in figure 1:

• Distributed
• Partially Consolidated
• Consolidated

Figure 1. The Evolution of MoD Network Architecture

Some of the differences among the architectures are: [per figure 1 above]

1. Points for Enforcing Quality of Service:
1. In the distributed model, this is done at the access node, L2 aggregator switch (subscriber QoS) as well as the B-RAS and the Edge Router (Service QoS). Synchronization is necessary among the devices.
2. On the opposite side, the consolidated model assumes that the Broadband Network Gateway (BNG) is the control point for enforcing QoS policies (both subscriber and service QoS).
2. Data Forwarding
1. In the distributed model, layer 2 and layer 3 forwarding states must be constantly synchronized between the L2 devices (L2 aggregator switch) and L3 (PE) nodes. This can create unnecessary congestion in the access network.
2. No external synchronization is required in the consolidated model
3. Required level of intelligence per device
1.  In the distributed, and partially consolidated models the access network (both the DSLAMs and the L2 aggregator switches) are expected to have much more intelligence than the consolidated architecture. This is necessary to be able to aggregate and manage QoS policies per subscriber.
4. Since the level of intelligence within a device has a direct relationship to its cost, the non-consolidated models become more expensive as the number of DSLAMs and L2 aggregator switches are much higher than BNGs. Keeping the service intelligence centralized allows devices that are closer to edge remain dumb and low cost.

SmartEdge can function as a highly-available, carrier-class subscriber management platform plus a Provider’s Edge Router or assume all three functionality including L2 aggregation, per figure 2. The deployment of the SmartEdge MSER functioning as a BNG in a consolidated architecture provides some clear technical advantages per above points.

Figure 2. Distributed Architecture for Delivery of Multiplay Services

Figure 3. Basic Logical Connectivity in a Consolidated Architecture

Additional technical and economic advantages of the SmartEdge MSER for deployment of IP-based multi-services are per figure 3:

1. No additional ports are necessary for inter-nodal communication as necessary in other architectures. Lowers overall CAPEX and OPEX.
2. Ability to allow the subscriber and/or provider to adjust services dynamically, e.g., increase/decrease bandwidth or QoS levels per service per subscriber. Allows for revenue source for the provider.
3. SmartEdge was built as a multi-service platform and did not evolve from a L2 aggregation platform or a B-RAS or a PE router. It has a consistent performance across all functions, with a highly resilient architecture, including a modular operating system.

SmartEdge is capable of delivering multimedia services based on:

• Layer 3 services by using Protocol Independent Multicast- PIM (using Sparse Mode – SM – for operational efficiency) to distribute specific IPTV channels. It has full support for IGMP v1, v2 and v3, with all flavors of PIM (SM, DM, and SSM), Multi-protocol BGP (MBGP) and Multicast Listener Discovery (MLD) v2.
• Layer 2 services by using a separate VPLS instance for each video head end and distributing the streams to all L2 switches that are members of that VPLS

The former is a better approach as the latter is usually used to emulate business LAN environment and not for IPTV delivery.

There are two generic methods of service delivery, from the network to the subscriber, that has been accepted as common practice in the industry: 1. Using one dedicated VLAN per subscriber per service 2. Using one dedicated VLAN per service. Both of these approaches are supported in SmartEdge.

The SmartEdge has been deployed in some of world’s most sophisticated networks, currently in service and offering triple play services to a large set of consumers and businesses alike. Case in point:

A North American service provider, a leader in delivery of voice and data services to residential and business customers opted to deploy the SmartEdge MSER SE800 to create a consolidated broadband network able to efficiently deliver triple play services for consumers and VPN services for businesses. By simplifying network design and operations, and enabling delivery of multiple services from a single platform, the SmartEdge empowered the service provider to accelerate the introduction of new services such as IPTV while mitigating the risk of unknown service adoption behaviors. Redback’s SmartEdge MSER enabled the provider to address all of these priorities with a highly flexible, scalable, and cost-effective service delivery platform.

By offering the SmartEdge SE800 MSER platform, the customer benefited from the ability to directly connect both types of DSLAMs (its existing ATM-based and the new Ethernet-based) and offer the same subscriber management policies, QoS treatment, and overall service creation capabilities across the entire customer base. This supported both the coexistence and graceful migration of users served by multiple generations of access equipment. The port density and session scalability of the SmartEdge MSER enabled this customer to adopt a fully consolidated aggregation model, where DSLAMs were directly connected, rather than consolidated with an intermediate aggregation network. Elimination of additional network elements reduced costs and complexity while creating a more manageable network with deterministic service delivery.

SmartEdge MSER, allowed the service provider to establish its IP/MPLS network to provide business services as well (L3 VPNs, for example). The customer’s high-level consolidated architecture designed with SE800 MSER is shown in figure 4.

Figure 4. High Level Consolidated Network Architecture-SmartEdge Customer