IS-IS Network Design Solutions

Case Study: Migration from Narrow to Wide Metrics

With the availability of IS-IS wide metrics support in IOS, operators of many existing networks have been considering migrating their configurations from narrow metrics to take advantage of the flexibility and convenience larger metric values provide. As discussed in the previous chapter, the easiest and least painful way to do this migration is by calling a flag day, shutting down the network, making appropriate changes, and turning the routers back up. However, stringent service level agreements (SLAs) in some environments prevent this approach. Fortunately, there are other options. There are actually two other approaches that are discussed in the following sections. Narrow metrics that allow ...