ch when you can and route when you have to." But in today's world of fast Layer-3 switching, this mantra no longer holds. With Layer-3 switches, you can route at switching speeds. For many people, Layer-3 redundancy is easier to understand than Layer-2 redundancy. As long as the business needs are met and the end result is the same, using routing to solve your redundancy concerns is perfectly acceptable. If you decide to use routing instead of switching, don't turn off spanning tree. Spanning tree will still protect against loops you might have missed. If you're using switches-even Layer-3 switches-spanning tree can be a lifesaver if someone plugs in a switch where it doesn't belong. Always Configure the Root Bridge Don't let spanning tree elect the root bridge dynamically. Decide which switch in your network should be the root, and configure it with a bridge priority of 1. If you let the switches decide, not only may they choose one that doesn't make sense, but switches added later may assume the role of root bridge. This will cause the entire network to reconverge and cause links to change states as the network discovers paths to the new root bridge. I once saw a large financial network in a state of confusion because the root bridge was a switch under someone's desk. The root bridge had not been configured manually, and when this rogue switch was added to the network, all the switches reconverged to it because it had the lowest MAC address of all the switches. While this may not sound like a big deal on the surface, the problem manifested itself because the main trunk between the core switches, which was the link farthest from the root bridge, became blocked. Chapter 8: Spanning Tree CHAPTER 9 Routing and Routers Routing is a term with multiple meanings in different disciplines. In general, it refers to determining a path for something. In telecom, a call may be routed based on the number being dialed or some other identifier. In either case, a path is determined for the call. Mail is also routed-I'm not talki