BGP local-pref
Local Preference — the BGP attribute that controls which outbound path an autonomous system prefers when there are several ways to reach a destination. Higher value wins. It's shared within the AS (via iBGP) but never advertised outward.
Role: local-pref is the FIRST criterion in BGP's decision process (before AS-path) → the most powerful tool for controlling how your network sends traffic OUT. Example: a company with two ISPs sets a higher local-pref on routes via the primary (cheaper/faster) link → all outbound traffic prefers it, with the other as a backup. Since it's shared via iBGP to all routers in the AS, the whole network gets a consistent view of which exit is preferred. Important distinction: local-pref controls OUTBOUND traffic (your choice); to affect INBOUND traffic you must influence others' choices (AS-path prepending, MED, communities). A core attribute in BGP traffic steering. Related to BGP AS-path and BGP MED.