3Com 10014299 manual Ospf ASE

408CHAPTER 26: IP ROUTING PROTOCOL

Routing Protocol or Type	Corresponding Routing Priority
OSPF ASE	150
EBGP	170
Unknown	255

Except for the direct route (Connected), the priority of each dynamic routing protocol can be manually configured according to specific requirements. In addition, each static route can have a different priority.

Support of the Route A backup route allows a router to automatically select another route to transmit Backup data packets when the line changes, and enhances the user network reliability. To

implement route backup, you can set a different priority to the multiple routes to the same destination. In fact, a user can set the highest priority to the route passing the main path, and take turns to reduce the priority to the routes passing backup paths. Normally, the router will send data through the main path. When a fault occurs on the line, the route will be hidden, and router will select the backup route with second-highest priority for data transmission. In this way, the switchover from the active interface to the backup interface is implemented. When the main path is recovered, the router recovers the route and begins reselecting routes. Since the recovered route has the highest priority, it selects this main route to transmit data.

Sharing Routes Learned As different protocols find different routes due to the various algorithms adopted by each protocol, the problem of sharing the findings of different protocols is of concern. On 3Com routers, a route learned by a routing protocol can be imported to another routing protocol. Each protocol has its own route import mechanism.