Enterprises' increasing reliance on video-based services such as global teleconferencing, VoIP, and digital media requirements are straining the service provider's network capability. These applications are as demanding as they are sensitive to shortfalls in bandwidth, latency, jitter and overall predictability. While less than voice quality might have been acceptable for older applications, enterprises need and will only accept superior delivery standards for these new services. 

To meet enterprises' changing requirements, service providers need to move beyond best-effort Internet era IP-VPNs to premium IP-VPNs to deliver faster, more flexible and extremely reliable services.

Premium IP-VPNs Establish a new Standard 

The dependence on multimedia and on-demand applications is an accelerating trend that is changing the way IP-VPNs are delivered to enterprises, as shown in Figure 1. In the past, a dedicated point-to-point connection served the needs of a limited business market. Now, a full range of vertical markets are looking to the service provider for a broad spectrum of sophisticated applications with very demanding performance and latency requirements. Service providers must adapt quickly to this changing environment to stay competitive and to ensure that their service offerings stand out in the market. 

Internet era IP-VPNs face considerable challenges when trying to meet the service requirements of today's businesses, particularly in terms of the requirements imposed by on-demand applications. Internet era IP-VPNs have significant limitations:

Premium IP-VPN services address each of these limitations head-on, establishing a dramatically higher standard for VPN services. 

Meet Customers' Expectations for Always-on Services

What was once considered good in terms of reliability is no longer sufficient for the new on-demand applications. In today's competitive environment, service providers must meet their customers' expectations for uninterrupted service, and to do that they need comprehensive high availability features. Most IP-VPN solutions can offer graceful restart, non-stop forwarding and protocol reconvergence features, but these features provide a mean time to repair (MTTR) measured in minutes. In most cases, that's simply not fast enough to avoid service interruptions. Premium IP-VPNs rely on non-stop service and non-stop routing features to provide a MTTR measured in milliseconds, which means no service disruption occurs.

Non-stop routing and non-stop services are achieved through control plane parallelization in the multiservice edger router (MSER). Up-to-date routing state information is constantly maintained on the standby control plane module. The standby module is also fully aware of the services and sessions, so there is zero downtime during a control plane failover. Service level guarantees are maintained at all times.

Interactive and real time enterprise applications are driving the need for always-on premium IP VPNs and require highly available networks that can provide 99.999 percent availability or better. Figure 2 illustrates how a premium IP-VPN solution can offer superior high availability features to ensure always-on IP-VPNs. 

Provide Quality Levels Tailored to Service Requirements

Enterprises need and expect guaranteed QoS levels for the different application types. How well this is done can be an important differentiator for service providers. Internet era IP-VPNs have traditionally been delivered over frame relay and ATM, which provide pre-provisioned circuits to ensure predictable delivery. However, as new multimedia and on-demand applications require greater bandwidth, Ethernet has become the technology of choice from a cost and performance standpoint. Ethernet poses a greater challenge for QoS and cannot ensure predictable delivery of IP-VPN services. 

Traditional Ethernet-based IP-VPN solutions will mostly support soft QoS, as shown in the top example of Figure 3. Soft QoS gives one service or traffic type relative precedence over other services or traffic types. It provides differentiation between traffic types, allowing a service provider to offer multiple service levels, but it fails to account for the need to provide bandwidth guarantees. A provider cannot guarantee bandwidth or low packet loss to an enterprise unless the provider significantly over-engineers its network to ensure that, in almost all scenarios, traffic is not discarded. 

Premium IP-VPNs over Ethernet support hard QoS, as shown in the bottom example of Figure 3. Hard QoS uses MPLS to enable a connection-oriented approach that can guarantee bandwidth for different services and reserve network resources along the path. 

To support the rapidly-growing volumes of business-critical and delay-sensitive traffic, hard QoS is necessary, as a means of guaranteeing deterministic bandwidth. For an enterprise to entrust its operations to an IP-VPN, the IP-VPN must provide quality controls that are comparable to those available in connection-oriented frame relay and ATM networks. 

In the bottom example of Figure 3 a premium IP-VPN service is delivered to enterprise customers. The service provider can implement hard QoS to tailor the service to the enterprise's applications' unique requirements. Advanced hierarchical scheduling is implemented through a tiered service level agreement (SLA) in which different QoS levels are provided through the premium IP-VPN service. For example, specific committed information rates (CIR) and peak information rates (PIR) can be set for each application riding the IP-VPN. In addition, an overall QoS level can be assigned to the collection of services used by a customer. This combined capability enables the service provider to cater to the dynamic traffic patterns of multimedia and on-demand applications.

A premium IP-VPN solution with advanced, flexible Quality of Service capabilities ensures applications such as video and VoIP have predictable delivery, even over Ethernet. Service providers can tailor the premium IP-VPN service to suit the end customer's requirement for the different traffic types, using different SLA arrangements.

Reduce OPEX with Efficient Management Tools

To ensure the long-term profitability of their businesses, service providers must be able to introduce and maintain new services cost effectively. One of the challenges they face is to improve overall operational efficiencies by:

As well, enterprise customers want a better window to track or request changes to their VPN service, anytime.

To ensure both the service provider's and enterprise's requirements are met, management systems must evolve beyond the disparate element management platforms to a service aware manager. Figure 4 provides an example of this, illustrating how the network is viewed as a single virtual node, simplifying service activation and assurance. Even if the end-to-end service rides over two different technologies, such as frame relay and Ethernet, a premium IP-VPN service is presented as one service.

A service aware manager provides a comprehensive set of network and service level OAM tools for fault management and the management of per-service performance metrics for latency, jitter and packet loss. These tools enable the operator to provide fast, accurate, efficient resolution of a customer's service problem. Where in the past it may have taken hours or days to resolve an issue, it can now be diagnosed in minutes and corrected. The customer's SLA is not compromised and the service provider benefits from reduced OPEX.

With detailed performance metrics, providers can offer enterprise customers web portals. These web portals can be used to provide customers with reports that demonstrate how their SLAs were met over time and what level of performance their traffic actually experienced over the network. Portals can also enable enterprises to change QoS levels on one of their services or increase bandwidth when necessary. These types of tools help service providers increase revenues.

MSER Delivers Premium IP-VPNs 

Traditional routers or Internet style routers were not designed to address the requirements of the multimedia and on-demand applications that enterprises are increasingly deploying. The multiservice edge router is a relatively new breed of service router that enables premium IP-VPNs. 

"In simple terms, the multiservice edge router is a highly scalable, flexible and resilient router optimized for converged IP/MPLS networks. The MSER supports diverse service interfaces, enforces QoS policies for both business and residential services, and operates on a scalable, reliable IP/MPLS control plane. In addition, it must be engineered to apply QoS, accounting and OAMP to specific services, not just ports or sub-interfaces."  Service Providers Define Key Requirements for Multiservice Edge Routers,  Yankee Group, October 2005

The MSER enables premium IP-VPNs to scale in multiple dimensions.

The Accelerating Trend to "Always On"

There are significant indications that the winds of change are getting stronger as Enterprises increase their use of multimedia, always-on applications -- changing the IP VPN landscape. And industry projections are that this trend will continue over the next five to ten years. To ensure success in this growth market, service providers need to enhance their service offerings to include premium IP-VPNs. Premium IP-VPNs establish a new standard by enriching Ethernet with deterministic characteristics. They provide the high availability, scalability, quality of service and management features necessary to serve enterprises' requirements today and tomorrow.