Creating Routing Tables

By default, the JUNOS software maintains three routing tables: one for unicast routes, one for multicast routes, and a third for Multiprotocol Label Switching (MPLS). You can configure additional routing tables to support situations where you need to separate out a particular group of routes or where you need greater flexibility in manipulating routing information. In general, most operations can be per- formed without resorting to the complexity of additional routing tables. However, creating additional routing tables has several specific uses, including importing interface routes into more than one routing table, applying different routing policies when exporting the same route to different peers, and providing greater flexibility with incongruent multicast topologies.

Creating routing tables is optional. If you do not create any, the JUNOS software uses its default routing tables, which are inet.0 for unicast routes, inet.1 for the multicast forwarding cache, and inet.3 for Multiprotocol Label Switching (MPLS). If Multiprotocol Border Gateway Protocol (MBGP) is enabled, inet.2 is used for subaddress family indicator (SAFI) 2 routes. If you configure a routing instance, the JUNOS software creates the default unicast routing table instance- name .inet.0 .

To add static, aggregate, generated, or martian routes to only the default unicast routing table ( inet.0 ), you do not have to create any routing tables because, by default, these routes are added to inet.0 . You can add these routes just by including the static , aggregate , generate , and martians statements at the [edit routing-options] hierarchy level.

To explicitly create a routing table, include the rib statement:

 [edit routing-options]  rib  routing-table-name  {   static {     defaults {  static-options  ;     }     rib-group  group-name  ;     route  destination-prefix  {       lsp-next-hop  lsp-name  {         metric  metric  ;         preference  preference  ;       }  next-hop  ;       qualified-next-hop  address  {         metric  metric  ;         preference  preference  ;       }  static-options  ;     }   }   aggregate {     defaults {  aggregate-options  ;     }     route  destination-prefix  {       policy  policy-name  ;  aggregate-options  ;     }   }   generate {     defaults {  generate-options  ;     }     route  destination-prefix  {       policy  policy-name  ;  generate-options  ;     }   }   martians {  destination-prefix   match-type  <allow>;   } } 

The routing table name includes the protocol family, optionally followed by a period and a number. The protocol family can be inet for the IP family or iso for the ISO protocol family. The number represents the routing instance. The first instance is 0.