Service providers are beginning to see success in rolling out IP services, whether it\'s wireline providers competing for television services or cable operators adding VoIP and streaming media to their existing high-speed internet offerings. Building on this success, service providers now need to scale their IP services, which are often media-rich applications that are bandwidth hungry and require stringent guarantees for that bandwidth. At the same time, they must increase the speed of offering these services while also reducing the cost of operating the overall network.
To achieve the service quality needed to deliver media-rich applications, service providers have had to compromise their original infrastructure goals of building simple and cheap metro Ethernet edge/aggregation networks. Instead, they have built multiservice metro networks with high-functioning equipment. Adopting this approach has gotten the job done, but metro networks are now complex and expensive to operate and don\'t deliver the service velocity providers need.
The common solution of over-provisioning the network simply won\'t work in today\'s world. It\'s not practical because users choose for themselves from a wide range of bandwidth-intensive applications and many of these applications take much of the available bandwidth. And because today\'s applications are media rich and quality sensitive, the degree of over-provisioning would need to rise considerably to deliver a quality experience.
Instead of being able to deploy simple, inexpensive Ethernet switches, service providers have been forced to select much higher functioning networking gear. Though the problems of multiservice metro networks are nothing like those of the internet backbone, many service providers have felt forced to deploy the gear originally designed for the internet core simply because the sophistication is there to successfully support multi-play services.
As service providers achieve success with their multi-play services, the strains between their original vision of a simple, cost-effective metro network and the network they actually built have become more apparent. And because the price of bandwidth continues to fall faster than Moore\'s law, the high cost of metro networks remains a critical issue for service providers.
The approach of managing services through network management or policy management does not scale to handle the constant pings and requests from all the elements in a large networks. If you want the network to be aware of these changes, you have to be able to configure the network in real time. In fact, most network managers are understandably reluctant to have a policy manager constantly changing the state of key network elements for fear of destabilizing the entire network.
Rethink the problem
Maybe the right place to start would be by separating the delivery of services from the transport of packets. If we started like this, then the transport layer would focus on packet delivery and no longer be service aware. Service providers could \'flatten\' the transport layer and eliminate protocols and complex configurations. They would then be able to purchase hardware optimized for price/performance metrics in a cost-effective manner. This would actually stimulate investment and innovation as well as new approaches to the transport layer.
Perhaps most important is the ability to create and deliver new services quickly. To do this, the network must be flexible to the needs of the actual services. The session layer would not provide packet transport but would provide session processing of all kinds: session initiation, management of the quality of service, and scaling these services to the increasing number of subscribers.