Just as wavelengths were tied to physical fibers before dense wave division multiplexing, today routing is tied to dedicated physical routers that have earned a reputation as being expensive and complex to manage. To improve IP performance and maximize the physical router resource, layers of frame relay and ATM networking are often added to IP networks (See Faster 'Net growth rate raises fears about routers).
To increase IP capacity, providers can install more physical routers at great expense and time -- by adding new fibers before DWDM, for example -- or gradually increase the size and speed of each physical router. The result is layers of costly equipment, slow provisioning and scaling barriers that block the potential of IP networking for today's enterprise users.
A new technology approach called dense virtual routed networking (DVRN) is designed to liberate the routing function from the constraints of monolithic physical routers that built today's Internet and private IP networks. DVRN promises to deliver improvements in scale and economies, and to enable a wealth of new IP-based services.
DVRN integrates three essential elements: dynamic virtual routing, optical-scale application quality of service (AQS) and collaborative service management.
With dynamic virtual routing, each virtual router is customizable and isolated from other virtual routers, allowing many virtual routers and virtual routed networks (VRN) to be supported in one system. Furthermore, each virtual router needs to support a full range of routing protocols, including Border Gateway Protocol 4 and Open Shortest Path First. And each dynamic virtual router must offer complete scalability, from a small private domain to the complete Internet route table.
Virtual routing is not a new concept, but DVRN bears little resemblance to the virtual router features available on a handful of systems today. These are largely limited by single-domain system architectures with just a customer-specific IP forwarding table, offering simple routing protocols, such as Routing Information Protocol, with small route tables.
These virtual routers are sufficient for today's low-end remote access and residential applications, but they lack the capabilities required for more demanding IP services.
DVRN's AQS is a transformation of quality of service beyond its traditional focus on reserving bandwidth for high-priority utilization toward enabling service over optical nets. AQS creates a new level of networking intelligence based on a highly granular and dynamic view of subscribers, applications, rules and statistics. AQS enables a DVRN system to "sense" a packet's contents by looking into its structure and make dynamic classification, queuing and forwarding decisions based on stateful application awareness and subscriber/policy provisioning. DVRN enables this packet processing at wire speed on ports running at optical rates.
Finally, DVRN's collaborative service management component unifies and controls the powerful underlying DVRN technology and addresses key issues facing service providers:
- It utilizes policy-based flow-through provisioning to accelerate VRN service creation and activation, and break the move/add/change backlog.
- It implements flexible and highly granular accountable entities that enable customized per-subscriber application-level service-level agreements and billing.
- It integrates secure and flexible partitioning among the different user roles in a VRN service environment, enabling end-user visibility and control, integration with service provider partners, and a full range of network operations center (NOC) and back-office tools and interfaces.
Once in place, a DVRN system is able to provide transparent network services to enterprise customers without interruption. Chassis-based DVRN systems are located in the service provider's points of presence (POP). These POP-based DVRN systems provide the dynamic virtual routing and AQS for each VRN. The collaborative service management software runs on servers in the NOC. It supports the full range of features needed to integrate effectively with operational support systems, directories, application services and NOC workflow processes. The goal of DVRN is to liberate the routing function from the constraints of physical routers.
This story, "Virtual routing promises new IP services" was originally published by Network World.