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What happens when a router has two routing protocols running and is receiving similar routes from each routing protocol?
Easy question, right? The routing protocol with the lower administrative distance has its routes installed in the routing table (routing information base – RIB).
However, an interesting question that comes up from time to time is this:

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Route summarization can be a good thing when done correctly. By summarizing a group of specific routes into one larger summarized (aggregate) route you can greatly improve the stability of the internetwork routing protocol. When a router advertises a summary it hides link failures and instabilities behind the summary from being seen by the rest [...]