Tom Nolle, CIMI Corp
04 Feb 2010
Convergence isn't an abstract concept if you expect tangible benefits. It means you'll be looking for devices that consolidate optical networking and electrical networking in a single box. The type of networking supported in both areas will depend on your current opto-electrical handling and your future plans and goals.
Unless you are installing a large amount of new greenfield gear, you can expect that your current operations practices will also have to be reviewed as a part of the convergence project.
Only a small part of the value of opto-electrical convergence comes from capital equipment economies; most of the benefit comes in operations savings. Network operators know that network complexity tends to be proportional to the number of devices, with the exponent depending on device connectivity.
That connectivity must be considered in normal geographic (or horizontal) terms, and in OSI-layer (or vertical) terms, so eliminating a layer of devices by consolidating two adjacent layers will significantly reduce complexity. It is important not to sacrifice capabilities in the consolidation, however, or you'll lose more than you gain in the operations expense (opex) area.
Converged opto-electrical devices must groom traffic connections at both the optical and electrical layers with the connection granularity your network requires.
If you currently route Gigabit Ethernet traffic in your Ethernet layer, you'll need to route it in an opto-electrical layer or add incremental Gigabit Ethernet grooming, which defeats the purpose of consolidating layers of devices. Similarly, if you route SONET Virtual Tributaries (VT), you'll either need to continue to groom or route them in your converged layer or restructure your network to avoid VT handling.
Another issue that can affect the value of opto-electrical convergence is the management interfaces and features available with the converged configuration.