Static routes are routes that are manually entered into the routing tables and are not advertised through the routing protocols. Static routes can be used to reach networks that are not advertised by routing protocols and do not have dynamic route entries in the routing tables. Static routes can also be used for security reasons, to create routes that are not advertised by the router.
Static routes are configured in the ExtremeXOS software, remain part of the configuration when the switch is rebooted, and are immediately available when the switch completes startup. Static routes are never aged out of the routing table, however, the Bidirectional Forwarding Detection (BFD) feature, can be used to bring down static routes when the host link fails.
Without BFD, static routes always remain operationally active because there is no dynamic routing protocol to report network changes. This can lead to a black hole situation, where data is lost for an indefinite duration. Because upper layer protocols are unaware that a static link is not working, they cannot switch to alternate routes and continue to use system resources until the appropriate timers expire.
With BFD, a static route is marked operationally inactive if the BFD session goes down. Upper layer protocols can detect that the static route is down and take the appropriate action.
A default route is a type of static route that identifies the default router interface to which all packets are routed when the routing table does not contain a route to the packet destination. A default route is also called a default gateway.