3Com 7700 Configuration Manual page 99

is the same as the cost of routes within the AS. Also, this route cost and the route
cost of the OSPF itself are comparable. That is, the cost to reach the external route
type 1 equals the cost to reach the corresponding ASBR from the local router plus
the cost to reach the destination address of the route from the ASBR
The external type-2 routes refers to imported EGP routes. Since these routes have
lower credibility, OSPF assumes that the cost from the ASBR to reach the
destinations beyond the AS is higher than the cost from within the AS to the
ASBR. So in route cost calculation, the cost to reach the external type 2 route
equals the cost to the destination address of the route from the ASBR. If the two
values are equal, then the cost of the router to the corresponding ASBR is
considered.
Perform the following configuration in OSPF view.
Table 42 Configure OSPF to Import the Routes of Other Protocols
Operation
Configure OSPF to impor
routes of other protocols
Cancel importing routing
information of other protocols
By default, OSPF does not import the routing information of other protocols.
The protocol variable specifies a source routing protocol that can be imported,
such as direct, static, RIP, or BGP.
Configure Parameters for OSPF to Import External Routes
When OSPF imports the routing information discovered by other routing protocols
in the autonomous system, some additional parameters need configuring, such as
the default route cost and the default tag of route distribution, as described in
Table 43. Route ID can be used to identify the protocol-related information. For
example, OSPF can use it to identify the AS number when receiving BGP.
Perform the following configuration in OSPF view.
Table 43 Configure Parameters for OSPF to Import External Routes
Operation
Configure the minimum interval for
OSPF to import the external routes
Restore the default value of the
minimum interval for OSPF to
import the external routes
Configure the upper limit to the
routes that OSPF import each time
Restore the default upper limit to
the external routes that can be
imported at a time
Configure the default cost for the
OSPF to import external routes
Restore the default cost for the
OSPF to import external routes
Command
import-route protocol [ cost value ] [ type value ] [ tag value
] [ route-policy route-policy-name ]
undo import-route protocol
Command
default interval seconds
undo default interval
default limit routes
undo default limit
default cost value
undo default cost
OSPF 91