Routing

HI,

static {
defaults {
preference 250;

route 0.0.0.0/0 {
next-hop [ 10.141.227.100 1.1.1.1 2.2.2.2 ];
qualified-next-hop 2.2.2.2;
preference 5;

could please some one help to understand this command and its features because once if we are giving next-hop IP  we can give prefernce/resolve/retain.

I need to know what is the difference in giving under defaults and with the next hop. (If a configuring after next hop as preference/ resolve/retai it works---but if i am configuring under default it wont )

I checked defaults passive but its not working.

Please help me to understand

"defaults" is an optional configuration under  [edit routing-options static].  The purpose of defaults option, is for all other static routes to inherit those static-options configured under the defaults hierarchy.

Route, next-hop, and qualified-next-hop, are not valid under defaults.  The attributes that are configurable under defaults are the following <static-options>.

See the following link for details on configuring static routes:

https://www.juniper.net/techpubs/en_US/junos13.1/topics/reference/configuration-statement/static-edit-routing-options.html

• (active | passive);
• as-path <as-path> <origin (egp | igp | incomplete)> <atomic-aggregate> <aggregator as-number in-address>;
• community [ community-ids ];
• (install | no-install);
• (metric | metric2 | metric3 | metric4) value <type type>;
• (preference | preference2 | color | color2) preference <type type>;
• (readvertise | no-readvertise);
• (resolve | no-resolve);
• (retain | no-retain);
• tag string;

Coul you please explain me about the Aggregate routes and generated routes?

http://www.juniper.net/techpubs/en_US/junos13.1/topics/concept/policy-aggregate-routes.html

Route aggregation allows you to combine groups of routes with common addresses into a single entry in the routing table. This decreases the size of the routing table as well as the number of route advertisements sent by the routing device.

An aggregate route becomes active when it has one or more contributing routes. A contributing route is an active route that is a more specific match for the aggregate destination. For example, for the aggregate destination 128.100.0.0/16, routes to 128.100.192.0/19 and 128.100.67.0/24 are contributing routes, but routes to 128.0.0.0./8 and 128.0.0.0/16 are not.

A route can contribute only to a single aggregate route. However, an active aggregate route can recursively contribute to a less specific matching aggregate route. For example, an aggregate route to the destination 128.100.0.0/16 can contribute to an aggregate route to 128.96.0.0/13.

http://www.juniper.net/techpubs/en_US/junos13.1/topics/topic-map/policy-generated-route.html

Generated routes are used as the route of last resort. A packet is forwarded to the route of last resort when the routing tables have no information about how to reach that packet’s destination. One use of route generation is to generate a default route to use if the routing table contains a route from a peer on a neighboring backbone.

A generated route becomes active when it has one or more contributing routes. A contributing route is an active route that is a more specific match for the generated destination. For example, for the destination 128.100.0.0/16, routes to 128.100.192.0/19 and 128.100.67.0/24 are contributing routes, but routes to 128.0.0.0./8, 128.0.0.0/16, and 128.100.0.0/16 are not.

A route can contribute only to a single generated route. However, an active generated route can recursively contribute to a less specific matching generated route. For example, a generated route to the destination 128.100.0.0/16 can contribute to a generated route to 128.96.0.0/13.

By default, when generated routes are installed in the routing table, the next hop is chosen from the primary contributing route.