A port authority wants inbound Internet traffic to prefer the primary ISP link and treat the secondary as backup. Which AS-path manipulation is the usual approach on the backup advertisement?
Select an answer to reveal the explanation.
Short Explanation
Prepending is taping extra copies of your ASN onto the backup flyer so the Internet sees a longer path and picks the primary. You’re making the backup look worse on purpose—without lying about someone else’s ASN.
Full Explanation
AS-path prepending lengthens the path advertised toward an upstream so remote best-path selection prefers the shorter primary advertisement. It is a common inbound traffic-engineering tool on backup eBGP links. Removing your ASN or relying on allowas-in does not implement that preference pattern and can break loop detection. MED on the primary alone does not lengthen the backup AS path seen by the global table.