Next Gen Switch/Router Design Issues

摘要

Last month, we argued that fundamental changes in demand have substantially altered the requirements for next-generation enterprise switch/routers. Not only will they need to become faster, but they also will need to support substantially increased functionality and become more programmable (see BCR, September 2004, pp. 54-59). We also argued that the requisite hardware doesn't exist. In this article, we wish to further the discussion by addressing the following questions: 1. Why are current switch/router and port/line card designs unable to support the necessary speed and functionality? 2. What are possible solutions? 3. Are new designs achievable any time soon? Before we can answer these questions, however, we need to establish some basic architectural groundwork on switch design (for an analogous discussion of line card design issues, see "What About Line Cards?", pp. 46-47).