Routing

I am trying to find a way to summarize routes "redistributed" from another IGP, say RIP, into OSPF.

 

For example, if I had an ASBR in Area 0 redistributing 100.100.0.0/24, 100.100.1.0/24, 100.100.2.0/24 and 100.100.3.0/24 from RIP to OSPF, I only want to advertise the 100.100.0.0/22 Type-5 LSA into the backbone.

 

This is possible in IOS with the use of the "summary-address" command.

 

So far as I can tell, Junos only does summarization at ABRs using "area-range" or "nssa area-range" commands.

 

Is this even possible in Junos, to do this on the ASBR itself?

 

Thanks,

 

Nic

#ospf
#iostojunos
#summarization

good question.
I also struggled with this one some time back. Here is an excellent blog entry that explains it:

http://noshut.blogspot.in/2012/03/ospf-external-route-summarization.html


HTH
#ASBR
#ospf
#lsa
#summarization

Thanks, that was helpful.

 

The salient points that I carried away are as follows, can someone verify -

 

1. No specific IOS equivalent "summary-address" command

2. Create an aggregate/generated route covering the desired routes

3. Instead of importing the IGP routes in the routing policy, import the aggregate/generated route

 

Would this workflow be the only possible way or does someone have a more streamlined flow?

 

Thank again,

 

Nic

#ospf
#iostojunos
#summarization

As of my understanding you are correct. 

yes, you're right. There is no single command that will summarize OSPF external routes on the ASBR.
The workaround mentioned on that blog post works fine though.

You could convert the area to nssa and then apply area-range command under the nssa stanza on the ABR, that will summerize external routes.