What is in this article?:
Creating a redundant network that cost-effectively maximizes the benefits of optical routing technology and configuration can look something like Figure 1.
In addition to redundancy benefits, a distributed network such as this is easy to scale. Expanding locations is as easy as adding a node. A new level of service capacity is also a welcome byproduct. Capabilities are encased within each node. If you take down or add a node, the system automatically resets to maintain operation and redundancy. Or, you may simply route around a node. Redundancy is achieved through the network, not the router itself. The only potential drawback is the number of components. This potential pain point of numerous components can easily be overcome with a management system that helps automate and run the system.
An example of a redundant architecture can be seen in Figure 2. Nodes 2, 3, 5 and 6 are made by 32 x 32 routers with 32 optical extensions (16 in/16 out), and nodes 1 and 4 are constructed by 64 x 64 routers with 64 optical extensions (32 in/32 out). Fibers can be broken and nodes can still be reached, as can routers, without dismantling the network. The architecture provides either a 96 x 96 non-blocking or blocking router scheme. Remembering that approximately 70 percent to 80 percent of a traditional star router is used for distribution, this solution may replace a 96 x 96 scheme. Also, it follows that several of the nodes are close enough together for electrical connectivity. This model could be a start to further system optimizations.
To add studios, sites or nodes, one would connect or alter a limited number of nodes affecting only part of the network. Most upgrade work would have moved from the hardware network to the software control system.
A management system that sits on top of this system is critical to providing redundancy and managing system components. The best ones use built-in algorithms to make decisions for the user and hide network operations complexity. For example, an “intelligent” management system will optimize a network’s resources by providing critical path finding. Techniques like shortest-path-first algorithms allow provisioning of the least-costly path from a source to one or more destinations, as well as diverse path routing to support redundancy and provide safest-possible routing. A network must predict all possible moves and the effect a move will have overall. Once a path is allocated, others are blocked.
The best choice is one that has the least-negative (less costly) impact, and intelligence is required to assess effects. Therefore, a cost system is built into the algorithm and enables the system to determine that.
While this is a clear factor in long-haul systems, it’s also significant for in-studio use. Network resources are precious, and efficiencies scale over time. State-of-the-art connection management can also enable dynamic connection on an as-needed basis. This helps achieve key flexibility in today’s pervasive live video setting.
A comprehensive management system should control and manage optical network nodes, while allowing the end user to view the system as a simple, point-to-point configuration that hides complexities of path finding and maintains workflow. All control should be provided by a simple interface that allows easy network configuration, maintenance, troubleshooting and problem resolution.
Getting full value
Distributed routing networks let the broadcaster take advantage of network topology by using low-cost electrical links for distribution, minimizing the number of optical links for >150ft/450ft transport, and creating redundancy for switching on separate routers. This ability readily exists.
Optical routing in a hybrid environment facilitates the ability to stay connected over a large range of ports and remain fully managed across all optical links. This is often not the case with more traditional configurations. Bringing all capabilities into a fully-managed environment enables users to take proactive action and positively impacts the whole value chain. Well-chosen routers, along with smart engineering, can create long-term efficiencies and cost benefits.
—Svein Haavard Haugen is director of engineering, Nevion.