Profitable IP Cores:  Built from the Edge
(continued)

The Importance of Routing

Internet-scale routing found in multi-service routers brings the knowledge of carrier network topology as well Internet topology that is critical for service providers to offer profitable services.   Routing intelligence gives service providers the ability to know where packets are coming from and where they're going, to provide multiple service levels and service level guarantees to customers, to shape and groom bandwidth and combine multiple services on a single infrastructure.

This knowledge can be used to make smart routing decisions (say to connect subscribers to content sources) and to implement service models that reflect the cost structures of distance sensitive billing, for example.  Without intelligent routing and the ability to become part of the IP infrastructure, the range of services described above is simply not achievable.

Delivering Advanced Services

Beyond routing, a number of other features must be in place to deliver advanced services. Without this functionality, providers cannot adequately guarantee and bill for advanced services.

Services and Service Management:

1)   Multiple service capabilities:  Edge devices must support ways of transporting existing ATM and Frame Relay traffic over the IP/MPLS backbone as well as offer new Ethernet Private Line (wide area Ethernet) services.  In addition, edge devices must support the new services that are increasingly in demand by customers, such as IP VPNs.   Without this capability, edge devices are not multi-service enabled.

2)   Accounting and classification driven by routing policy:  This means that carriers can now deliver multiple services from a common edge platform in a consistent fashion.  As packets are transported across the network, the multi-service router contains the intelligence required to determine what services are tied to what customer and to meet SLAs.  This functionality becomes increasingly important with the increasing shift to a retail service model.   It also provides the flexibility for service providers to bill based on usage, offer destination-based billing models, offer different service models for retail and wholesale customers, or bundle transit and peering services (in the case of an ISP who today typically offers those services on separate links).

Traffic Management:  This critical functionality includes a number of components.

1)   Per-customer class based queues:  This allows providers to meet SLAs while providing distinct service classes for each customer on a single infrastructure. Without this granularity, service providers must build a separate infrastructure for each service.

2)   Per-customer traffic shaping and policing:  This gives providers the ability to deliver the amount of bandwidth purchased by customers.  Without this, customers get either too much or too little bandwidth – neither scenario is optimal for either provider or customer.

3)   Packet classification, filtering and marking:  This enables differentiated services based on IP source/destination or application.   All packet classification, filtering and marking occurs at the multi-service router, with service transparency in the core.  

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