Applying Route-Filters

Procedure

• Apply route-filters to OSPF.

  Route-filters can be used in OSPF route selection and interaction between OSPF and other routing protocols. Table 1 lists usage scenarios and relevant configuration tasks.

  Table 1 Route-filter application in OSPF

  Usage Scenario	Relevant Configuration Task
  Use a route-filter to filter the routes to be imported by OSPF.	Configuring OSPF to Import External Routes
  Use a route-filter to filter the default routes to be imported by OSPF.	Configuring OSPF to Import a Default Route
  Use a route-filter to filter LSAs in an Area.	Configuring OSPF to Filter LSAs in an Area
  Use a route-filter to filter the routes received by OSPF.	Configuring OSPF to Filter Received Routes

• Apply route-filters to RIP.

  Route-filters can be used in RIP route selection and interaction between RIP and other routing protocols. Table 2 lists usage scenarios and relevant configuration tasks.

  Table 2 Route-filter application in RIP

  Usage Scenario	Relevant Configuration Task
  Use a route-filter to filter the routes to be imported by RIP.	Configuring RIP to Import External Routes
  Use a route-filter to filter the default routes to be advertised by RIP.	Configuring RIP to Advertise Default Routes

• Apply route-filters to RIPng.

  Route-filters can be used in interaction between RIPng and other routing protocols. Table 3 lists usage scenarios and relevant configuration tasks.

  Table 3 Route-filter application in RIPng

  Usage Scenario	Relevant Configuration Task
  Use a route-filter to filter the routes to be imported by RIPng.	Configuring RIPng to Import External Routes

• Apply route-filters to IS-IS.

  Route-filters can be used in IS-IS route selection and interaction between IS-IS and other routing protocols. Table 4 lists usage scenarios and relevant configuration tasks.

  Table 4 Route-filter application in IS-IS

  Usage Scenario	Relevant Configuration Task
  Use a route-filter to control IS-IS route leaking.	Configure IPv4 IS-IS route leaking Configure IPv6 IS-IS route leaking
  Use a route-filter to control IS-IS default route generation.	Configure IS-IS to generate default IPv4 routes Configure IS-IS to generate default IPv6 routes
  Use a route-filter to filter the routes to be imported by IS-IS.	Configure IS-IS to import external IPv4 routes Configure IS-IS to import external IPv6 routes

• Apply route-filters to BGP.

  Route-filters can be used to set BGP route attributes and filter the routes to be imported, advertised, or received. Table 5 lists usage scenarios and relevant configuration tasks.

  Table 5 Route-filter application in BGP

  Usage Scenario	Relevant Configuration Task
  Use a route-filter to set a priority for BGP routes.	Setting the BGP Priority
  Use a route-filter to filter the routes to be imported by BGP.	Configuring BGP to Import Routes
  Use a route-filter to filter the routes to be advertised by BGP.	Using XPL to Filter the BGP Routes to Be Advertised
  Use a route-filter to filter the routes to be received by BGP.	Using XPL to Filter the BGP Routes to Be Received

• Apply route-filters to BGP4+.

  Route-filters can be used to set BGP4+ route attributes and filter the routes to be imported, advertised, or received. Table 6 lists usage scenarios and relevant configuration tasks.

  Table 6 Route-filter application in BGP4+

  Usage Scenario	Relevant Configuration Task
  Use a route-filter to set a priority for BGP4+ routes.	Configuring BGP4+ to Import Routes
  Use a route-filter to filter the routes to be imported by BGP4+.	Setting the BGP4+ Priority
  Use a route-filter to filter the routes to be advertised by BGP4+.	Using XPL to Filter the BGP4+ Routes to Be Advertised
  Use a route-filter to filter the routes to be received by BGP4+.	Using XPL to Filter the BGP4+ Routes to Be Received