In Cisco IOS and Cisco IOS XE Software images, when redistributing routes from other routing
protocols into OSPF, what is a common reason why some of the routes might not be redistributed
into OSPF?
A.
The OSPF external metric type (E1 or E2) is not defined.
B.
The OSPF seed metric is not defined.
C.
The OSPF level (Level 1, Level 2, or Level-1-2) to which the routes will be redistributed into is
not defined.
D.
The subnets option in the redistribute command is missing.
Explanation:
When routes are redistributed, you must define a metric that is understandable to the receiving protocol. There are two methods to define metrics when redistributing routes.
You can define the metric for that specific redistribution only:
router rip
redistribute static metric 1
redistribute ospf 1 metric 1
Or you can use the same metric as a default for all redistribution (Using the default-metric command saves work because it eliminates the need for defining the metric separately for each redistribution.):
router rip
redistribute static
redistribute ospf 1
default-metric 1
If a metric is not specified, OSPF puts a default value of 20 when redistributing routes from all protocols except Border Gateway Protocol (BGP) routes, which get a metric of 1.
When there is a major net that is subnetted, you need to use the keyword “subnets” to redistribute protocols into OSPF. Without this keyword, OSPF only redistributes major nets that are not subnetted.
router ospf 1
network 131.108.0.0 0.0.255.255 area 0
redistribute isis metric 10 subnets
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Evrythings rigth jslaven, but…
Default redistribution metric for xxx to OSPF is 20 (E2) or 1(E2) for BGP.
The correct answer is subnet (as reported) becasue in IOS and IOS XE not classfull network are not redistribuited automatically; IOS XR it does.
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