Understanding Static Route Preferences and Qualified Next Hops

A static route destination address can have multiple next hops associated with it. In this case, multiple routes are inserted into the routing table, and route selection must occur. Because the primary criterion for route selection is the route preference, you can control the routes that are used as the primary route for a particular destination by setting the route preference associated with a particular next hop. The routes with a higher preference are always used to route traffic. When you do not set a preferred route, traffic is alternated between routes in round-robin fashion.

In general, the default properties assigned to a static route apply to all the next-hop addresses configured for the static route. If, however, you want to configure two possible next-hop addresses for a particular route and have them treated differently, you can define one as a qualified next hop.

Qualified next hops allow you to associate one or more properties with a particular next-hop address. You can set an overall preference for a particular static route and then specify a different preference for the qualified next hop. For example, suppose two next-hop addresses (10.10.10.10 and 10.10.10.7) are associated with the static route 192.168.47.5/32. A general preference is assigned to the entire static route, and then a different preference is assigned to only the qualified next-hop address 10.10.10.7. For example:

In this example, the qualified next hop 10.10.10.7 is assigned the preference 2, and the next-hop 10.10.10.10 is assigned the preference 6.

Related Topics

• Junos OS Feature Support Reference for SRX Series and J Series Devices
• Example: Controlling Static Route Selection