Which command can be used to avoid BGP suboptimal routing?

To avoid BGP suboptimal routing, using the command to summarize routes manually is an effective approach. Route summarization condenses multiple individual routes into a single, summarized route. This not only reduces the number of routes in the BGP routing table, which can help improve routing efficiency, but it also minimizes the likelihood of suboptimal routing scenarios arising from having too many specific routes being advertised.

When BGP routers have to manage a large number of individual routes, the potential for inefficient routing decisions increases. By summarizing these routes, the complexity is reduced, which allows BGP to make better and more optimal routing decisions. As a result, the summarized route can lead to shorter paths and more efficient use of network resources.

The other options, while valid in different contexts, do not directly address the issue of reducing suboptimal routing to the same extent as manual route summarization does. Route filtering can help control which routes are advertised or accepted but doesn’t inherently affect optimal routing. Route reflection is useful for reducing BGP peering requirements but may not directly improve routing paths. Route aggregation, although similar to summarization, typically refers to the process applied at the level of the IGP or within different protocols rather than BGP specifically.