BGP4 (Border Gateway Protocol) is the language that makes possible to keep up to date the road maps in the internet. This routing protocol is the one used by the big networks to exchange routing information. Thus, its performance is critical for the internet. In some situations the behavior of this protocol is not the desired one. This thesis (Or project) intends to analyze one of this problems together with some proposed solutions. This analysis will involve a review of the theory behind the proposals and a later simulation to test the performance of them. After the analysis is done, the proposals considered as useful will be implemented over an open source, free routing software, GNU Zebra. This work began as the analysis of the main proposal, the Ghost-Flushing rule.