Understanding Route Preference Values (Administrative Distance)
The Junos OS routing protocol process assigns a default preference value (also known as an administrative distance) to each route that the routing table receives. The default value depends on the source of the route. The preference value is a value from 0 through 4,294,967,295 (232 – 1), with a lower value indicating a more preferred route. Table 1 lists the default preference values.
Table 1: Default Route Preference Values
How Route Is Learned
Statement to Modify Default Preference
Directly connected network
Static and Static LSPs
Note: In Junos OS Releases prior to 10.4, if you configure a static MPLS LSP using the static-path statement, the default preference value is 5. Starting in Junos OS Release 10.4, if you configure a static-label-switched-path the default preference value is 6. The previous configuration statement static-path is hidden in Junos OS Release 10.4 and later releases.
RSVP preference as described in the MPLS Applications User Guide
LDP preference, as described in the MPLS Applications User Guide
OSPF internal route
IS-IS Level 1 internal route
IS-IS Level 2 internal route
OSPF AS external routes
IS-IS Level 1 external route
IS-IS Level 2 external route
BGP preference, export, import
In general, the narrower the scope of the statement, the higher precedence its preference value is given, but the smaller the set of routes it affects. To modify the default preference value for routes learned by routing protocols, you generally apply routing policy when configuring the individual routing protocols. You also can modify some preferences with other configuration statements, which are indicated in the table.