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OSPF Redistribution of Connected

What is the purpose of redistributing connected interfaces?

Is there a technote that I can reference?

Can someone provide an example?

Thanks in advance.

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Re: OSPF Redistribution of Connected

Hi there,

The redistribution of connecrted networks into OSPF can make a router into an ASBR.

Redistributing any routes into OSPF causes the route to be an external route.  External route LSAs are type 5 generally.

In OSPF the network command under the routing process tells the router which interfaces to have OSPF running on.  If the network command didn't include a particular interface and for some reason, rather than putting that network command in, you can choose to redistribute the interface network into OSPF.  Any redistirbution causes the route to be external, and hence causes the router to be an ASBR.  An ASBR is a boundary between the OSPF domain and anywhere else .

An external route generally defaults to an E2 type route, which has a metric of 20 (i think).  That metric does not include the metric to the ASBR  from within the ospf area.  Exrternal type E1 routes do include the metric + the 20.

This document may help.  http://www.cisco.com/en/US/docs/internetworking/technology/handbook/OSPF.html

Hope that helps, and can you please rate if you think it does?

Thanks,

Brad

1 REPLY
Bronze

Re: OSPF Redistribution of Connected

Hi there,

The redistribution of connecrted networks into OSPF can make a router into an ASBR.

Redistributing any routes into OSPF causes the route to be an external route.  External route LSAs are type 5 generally.

In OSPF the network command under the routing process tells the router which interfaces to have OSPF running on.  If the network command didn't include a particular interface and for some reason, rather than putting that network command in, you can choose to redistribute the interface network into OSPF.  Any redistirbution causes the route to be external, and hence causes the router to be an ASBR.  An ASBR is a boundary between the OSPF domain and anywhere else .

An external route generally defaults to an E2 type route, which has a metric of 20 (i think).  That metric does not include the metric to the ASBR  from within the ospf area.  Exrternal type E1 routes do include the metric + the 20.

This document may help.  http://www.cisco.com/en/US/docs/internetworking/technology/handbook/OSPF.html

Hope that helps, and can you please rate if you think it does?

Thanks,

Brad

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