In my documents, I stated that “shorter, consistent AS_PATHs propagate more effectively” and that AS_PATH lengths influence route preference. To be precise:
BGP Route Selection and AS_PATH According to RFC 4271, Section 9 (BGP Route Selection Process): "Remove from consideration all routes that are not tied for having the smallest number of AS numbers present in their AS_PATH attributes" This means that, when local preference, MED, origin type, and other selection criteria are equal, BGP will prefer the route with the shorter AS_PATH. Clarification on “propagation” and “credibility” I do not mean that AS_PATH length directly affects the credibility of the origin or guarantees propagation. It was a mistake in expression that I take responsibility for. Actual propagation is determined by operator filtering policies, RPKI/ROA validation, and peer relationships. What I intended to highlight in the tool is that shorter AS_PATHs may indicate routes more likely to be selected internally within a network, which indirectly informs risk modeling of high-impact BGP hijacks. _______________________________________________ NANOG mailing list https://lists.nanog.org/archives/list/[email protected]/message/PIAYFMXBL7ZMQTRBZIOUXXUYVK3UV2V5/
