3Com 10014299 manual Displaying Debugging Routing Table, Preference, Other parameters

Displaying and Debugging the Routing Table 411

IP address to the link layer address (such as dialer route ip, x.25 map ip or fr map ip commands, and so on). In this case, you cannot specify the transmitting interface for the static route and must configure the IP address of the next hop.

Actually, all the route items must mark the address of the next hop. According to the destination address of packets, an IP router searches for the matching route in the routing table. Only when the address of next hop is specified in the route, can the link layer find a corresponding address through this address and transfer packets.

However, in certain cases (such as PPP encapsulated in link layer), the address of the node on the other end may be unknown when the router is configured so that the sending interface has to be specified. In addition, if the sending interface has been specified, it is not necessary to change the router's configuration when the address of the node connected on the other end is changed

■Preference

Different preference configurations can achieve flexible route management. For example, when configuring multiple routes to the same destination, if the same preference is designated, load balancing can be realized. If different preferences are designated, route standby can be realized.

■Other parameters

Configuring a Default Route

The reject and blackhole attributes refer to unreachable routes and black hole routes respectively.

Perform the following configurations in system view.

Table 467 Configure a Default Route

Operation	Command
Configure a default	ip route-static 0.0.0.0 { 0.0.0.0 0 } {
route	interface-type interface-number nexthop-address
	} [ preference value	] [ reject blackhole ]
Delete a default route	undo ip route-static	0.0.0.0 { 0.0.0.0 0 } [
	interface-type interface-number nexthop-address
	] [ preference value	]

The parameters of this command mean the same as those in static route configuration.

Displaying and

Debugging the

Routing Table

Table 468 Displaying and Debugging the Routing Table

Operation	Command
Display the abstract information of the	display ip routing-table
routing table
Display the information of specific route	display ip routing-table ip-address
Display the detailed information of the	display ip routing-table verbose
routing table
Display the radix information of the	display ip routing-table radix
routing table
Display the static routing table	display ip routing-table static