Riverstone Networks WICT1-12 - Manual (Page 432)

18-2 Riverstone Networks RS Switch Router User Guide Release 8.0
Preference Routing Policy Configuration
18.1.1 Import Policies
Import policies control the importation of routes from routing protocols and their installation in the routing databases
(Routing Information Base and Forwarding Information Base). Import Policies determine which routes received from
other systems are used by the RS routing process. Every import policy can have up to two components:
• Import-Source
• Route-Filter
Import-Source
This component specifies the source of the imported routes. It can also specify the preference to be associated with the
routes imported from this source.
The routes to be imported can be identified by their associated attributes:
• Type of the source protocol (RIP, OSPF, BGP).
• Source interface or gateway from which the route was received.
• Source autonomous system from which the route was learned.
• AS path associated with a route. Besides autonomous system, BGP also supports importation of
routes using AS path regular expressions and AS path options.
• If multiple communities are specified using the optional-attributes-list, only updates carrying all of
the specified communities will be matched. If the specified optional-attributes-list has the value
none
for the
well-known-community
option, then only updates lacking the community attribute
will be matched.
Table 18-1 Default preference values
Preference Defined by CLI Command Default
Direct connected networks
ip-router global set interface
0
OSPF routes
ospf
10
Static routes from config
ip add route
60
RIP routes
rip set preference
100
Point-to-point interface 110
Routes to interfaces that are down
ip-router global set interface
down-preference
120
Aggregate/generate routes
aggr-gen
130
OSPF AS external routes
ospf set ase-defaults preference
150
BGP routes
bgp set preference
170
,6,6 URXWHV
isis set preference