3Com SuperStack 4 Configuration Manual page 131

virtual link refers to a logic channel set up through the area of a non-backbone
internal route between two ABRs. Both ends of the logic channel should be ABRs
and the connection can take effect only when both ends are configured. The
virtual link is identified by the ID of the remote router. The area, which provides
the ends of the virtual link with a non-backbone area internal route, is called the
transit area. The ID of the transit area should be specified during configuration.
The virtual link is activated after the route passing through the transit area is
calculated, which is equivalent to a P2P connection between two ends. Therefore,
similar to the physical interfaces, you can also configure various interface
parameters on this link, such as an hello timer.
The "logic channel" means that the multiple routers running OSPF between two
ABRs only take the role of packet forwarding (the destination addresses of the
protocol packets are not these routers, so these packets are transparent to them
and the routers forward them as common IP packets). The routing information is
directly transmitted between the two ABRs. The routing information refers to the
type-3 LSAs generated by the ABRs, for which the synchronization mode of the
routers in the area will not be changed.
Perform the following configuration in OSPF Area View.
Table 148 Configuring OSPF Virtual Link
Operation
Create and configure a virtual link
Remove the created virtual link
The and
area_id router_id
By default, hello timer is 10 seconds, retransmit 5 seconds, trans-delay 1 second,
and the dead timer is 40 seconds.
Configuring the OSPF Area to Support Packet Authentication
All the routers in an area must use the same authentication mode. In addition, all
routers on the same segment must use the same authentication key password.
Use the
authentication-mode simple
authentication password for the area, and the
command to configure the MD5 authentication password.
Perform the following configuration in OSPF Area View.
Table 149 Configuring the OSPF Area to Support Packet Authentication
Operation
Configure the area to support
authentication type
Cancel the authentication attribute
of this area
By default, the area does not support packet authentication.
Command
router_id
vlink-peer
seconds
retransmit
seconds
| dead | simple
keyid key ]*
undo vlink-peer
have no default value.
command to configure a simple
authentication-mode md5
Command
authentication-mode { simple | md5 }
undo authentication-mode
OSPF Configuration
seconds
[ hello
seconds
| trans-delay
password
| md5
router_id
143
|