LOCAL_PREF controls which exit point your AS uses for outbound traffic. Higher values are preferred.
Scope: Only exchanged within your AS (iBGP). Never sent to eBGP peers.
Default value: Typically .
Example use case: You connect to ISPs. ISP-A is your primary. ISP-B is backup.
- Routes from ISP-A: set LOCAL_PREF to
- Routes from ISP-B: set LOCAL_PREF to
Now all routers in your AS prefer ISP-A for outbound traffic. If ISP-A fails, routes through ISP-B (with LOCAL_PREF ) take over.
LOCAL_PREF wins early in the BGP decision process, making it powerful for policy.