User's Manual

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Users Manual of CS-6306R
45.3.3.8 Generating Default Route
ASBR requires generating a default route to enter the OSPF route area. When you configure the switch to
distribute the route to the OSPF area, the route automatically becomes ASBR. However, default ASBR does
not generate the default route to enter the OSPF routing area.
Run the following command in switch configuration mode to force ASBR to generate the default route.
Command Purpose
default-information originate [always]
[route-map map-name]
Forces ASBR to generate the default
route.
45.3.3.9 Choosing Route ID Through the LOOPBACK Interface
OSPF takes the maximum IP address configured on the interface as the switch ID. If the interface connecting
the IP address changes to the Down state, or the IP address is cancelled, the OSPF process is to recalculate
the new switch ID and resend the routing information from all interfaces.
If a loopback interface is configured with the IP address, the switch takes its IP address as its ID. The
loopback interface will never be at the down state. Therefore, the routing table is stable.
The switch preferentially takes the loopback interface as the switch ID. It also chooses the maximum IP
address as the switch ID. If the loopback interface does not exist, the maximum IP address of the switch is
taken as the switch ID. You cannot specify OSPF to use any special interface.
Run the following command in global configuration mode to configure the IP loopback interface:
Command Purpose
interface loopback 0
Creates a loopback interface and enters the interface configuration mode.
ip addressip-address mask
Distributes an IP address for an interface.
45.3.3.10 Configuring OSPF Management Distance
The management distance stands for the credit level of the routing information source, such as the single
switch or a group of switches. Generally, the management distance is an integer between 0 and 255. The
bigger the number is, the lower the credit level is. If the management distance is 255, the routing information
source is not trusted or should be omitted.
OSPF uses three kinds of different management distances: intra-area, inter-area and external. The routes in
an area are called intra-area routes; routes to other areas are called inter-area routes; routes that are
distributed from other routing protocol areas are called external routes. The default value of each type of
routes is 110.
Run the following command in switch configuration mode to configure the distance vale of OSPF.
Command Purpose
distance ospf [intra-area dist1]
[inter-area dist2] [external dist3]
Modifies the management distance
value of the intra-area routes,
inter-area routes and external routes.