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DES-7200 Configuration Guide Chapter 4 OSPF
Configuration
4-7
Command Meaning
DES-7200 (config-if)#end
Return to the privileged EXEC mode.
DES-7200 #show ip ospf [process-id]
interface [interface-id]
Display the routing protocol that is running
currently.
DES-7200 # write
(Optional) Save the configuration.
You can use the no form of the above commands to cancel or restore the
configuration to the default.
4.2.3 Configuring the OSPF to Adapt to Different Physical Networks
According to the transmission nature of different media, the OSPF divides the
networks into three types:
Broadcast network (Ethernet, token network, and FDDI)
Non-broadcast network (frame relay, X.25)
Point-to-point network (HDLC, PPP, and SLIP)
The non-broadcast networks include two sub-types according to the operation
modes of the OSPF:
One is the Non-broadcast Multi-access (NBMA) network. The NBMA
requires direct communication for all routers interconnected. Only fully
meshed networks can meet this requirement. If the SVC (for example, X.25)
connection is used, this requirement can be met. However, if the PVC (for
example, frame relay) networking is used, there will be some difficulty in
meeting this requirement. The operation of the OSPF on the NBMA network
is similar to that on the broadcast network: One Designated Router must be
elected to advertise the link status of the NBMA network.
The second is the point-to-multipoint network type. If the network topology is
not a fully meshed non-broadcast network, you need to set the network type
of the interface to the point-to-multipoint network type for the OSPF. In a
point-to-multipoint network type, the OSPF takes the connections between
all routers as point-to-point links, so it does not involve the election of the
designated router.
Whatever the default network type of the interface, you must set it to the
broadcast network type. For example, you can set the non-broadcast
multi-access network (frame relay, X.25) to a broadcast network. This spares the
step to configure the neighbor when you configure the OSPF routing process. By
using the X.25 map and Frame-relay map commands, you can allow X.25 and
frame relay to have the broadcast capability, so that the OSPF can see the
networks like X.25 and frame relay as the broadcast networks.