Route summarization

- [Instructor] Routes that are shared between neighbors…can also be manipulated via route summarization.…Route summarization,…often referred to as just summarization,…allows an administrator to suppress component routes…and instead advertise a larger subnet in their place.…This can lower resource utilization on routers…as they don't have to store high volumes of component routes…as well as fluctuation in those component routes…is hidden from the downstream routers…so path recomputation isn't necessary.…

Say for example 10.0.0.0/24, 10.0.1/24 and 10.0.2/24…could all be summarized inside of 10.0.0.0/22.…Something of note is the metric for the summary route.…It is configured as the best metrics…of the component routes.…Configuration of summarization is the easy part.…It's the design and planning that can be difficult.…Summarization is configured per interface…with the ip summary-address command.…

Once enabled, four things happen.…All neighbors on that interface reestablish…and all routes learned to the neighbors are cleared.…