Supported Platforms
Related Documentation
- ACX, M, MX, PTX, QFX, T Series
- Example: Configuring the Local Preference Value for BGP Routes
Understanding the BGP Local Preference
Internal BGP (IBGP) sessions use a metric called the local preference, which is carried in IBGP update packets in the path attribute LOCAL_PREF. When an autonomous system (AS) has multiple routes to another AS, the local preference indicates the degree of preference for one route over the other routes. The route with the highest local preference value is preferred.
The LOCAL_PREF path attribute is always advertised to IBGP peers and to neighboring confederations. It is never advertised to external BGP (EBGP) peers. The default behavior is to not modify the LOCAL_PREF path attribute if it is present.
The LOCAL_PREF path attribute applies at export time only, when the routes are exported from the routing table into BGP.
If a BGP route is received without a LOCAL_PREF attribute, the route is stored in the routing table and advertised by BGP as if it were received with a LOCAL_PREF value of 100. A non-BGP route that is advertised by BGP is advertised with a LOCAL_PREF value of 100 by default.
Related Documentation
- ACX, M, MX, PTX, QFX, T Series
- Example: Configuring the Local Preference Value for BGP Routes
Published: 2012-12-08
Supported Platforms
Related Documentation
- ACX, M, MX, PTX, QFX, T Series
- Example: Configuring the Local Preference Value for BGP Routes
