Technical Documentation

Default Route Preference Values

The JUNOS Software routing protocol process assigns a default preference value 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

Default Preference

Statement to Modify Default Preference

Directly connected network

0

System routes

4

Static and Static LSPs

5

static

RSVP-signaled LSPs

7

RSVP preference as described in the JUNOS MPLS Applications Configuration Guide

LDP-signaled LSPs

9

LDP preference, as described in the JUNOS MPLS Applications Configuration Guide

OSPF internal route

10

OSPF preference

IS-IS Level 1 internal route

15

IS-IS preference

IS-IS Level 2 internal route

18

IS-IS , preference

Redirects

30

Kernel

40

SNMP

50

Router discovery

55

RIP

100

RIP preference

RIPng

100

RIPng preference

PIM

105

JUNOS Multicast Protocols Configuration Guide

DVMRP

110

JUNOS Multicast Protocols Configuration Guide

Aggregate

130

aggregate

OSPF AS external routes

150

OSPF external-preference

IS-IS Level 1 external route

160

IS-IS external-preference

IS-IS Level 2 external route

165

IS-IS external-preference

BGP

170

BGP preference, export, import

MSDP

175

JUNOS Multicast Protocols Configuration Guide

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. For information about defining and applying routing policies, see the JUNOS Policy Framework Configuration Guide.


Published: 2010-04-14