12-07-2013 11:07 AM - edited 03-04-2019 09:47 PM
Hello,
I am starting to play with OSPF in GNS3 and I cannot get my routes to summarize in the routing tables of R1 and R2. The routing tables are as follows:
R1#sh ip route
Gateway of last resort is not set
1.0.0.0/32 is subnetted, 1 subnets
C 1.1.1.1 is directly connected, Loopback10
10.0.0.0/8 is variably subnetted, 10 subnets, 2 masks
O 10.2.10.0/24 [110/20] via 10.0.0.6, 00:18:04, FastEthernet0/1
C 10.1.3.0/24 is directly connected, Loopback3
C 10.1.2.0/24 is directly connected, Loopback2
C 10.1.1.0/24 is directly connected, Loopback1
C 10.0.0.0/30 is directly connected, FastEthernet0/0
C 10.0.0.4/30 is directly connected, FastEthernet0/1
C 10.1.4.0/24 is directly connected, Loopback4
O 10.2.30.0/24 [110/20] via 10.0.0.6, 00:18:05, FastEthernet0/1
O 10.2.20.0/24 [110/20] via 10.0.0.6, 00:18:05, FastEthernet0/1
O 10.2.40.0/24 [110/20] via 10.0.0.6, 00:18:05, FastEthernet0/1
R1#
---------------------------------------------------------------------------------------------------------------
R2#sh ip route
Gateway of last resort is not set
10.0.0.0/8 is variably subnetted, 10 subnets, 3 masks
C 10.2.10.0/24 is directly connected, FastEthernet0/1.10
O 10.1.2.1/32 [110/11] via 10.0.0.5, 06:05:30, FastEthernet0/0
O 10.1.3.1/32 [110/11] via 10.0.0.5, 06:05:30, FastEthernet0/0
O 10.0.0.0/30 [110/20] via 10.0.0.5, 06:05:30, FastEthernet0/0
O 10.1.1.1/32 [110/11] via 10.0.0.5, 06:05:30, FastEthernet0/0
O 10.1.4.1/32 [110/11] via 10.0.0.5, 06:05:30, FastEthernet0/0
C 10.0.0.4/30 is directly connected, FastEthernet0/0
C 10.2.30.0/24 is directly connected, FastEthernet0/1.30
C 10.2.20.0/24 is directly connected, FastEthernet0/1.20
C 10.2.40.0/24 is directly connected, FastEthernet0/1.40
R2#
I have put in summary addresses in the configs of both routers (attached) but R1's routing table won't summarize the 10.2.x.x networks and R2 won't summarize the 10.1.x.x networks. Am I doing something wrong?
Thanks in advance
Matt
Solved! Go to Solution.
12-07-2013 11:32 AM
Hi,
you can't summarize or filter within the same OSPF area because the link-state databases have to be the same on all routers in an area.
You can summarize OSPF internal routes on ABRs (area border router) between areas and external routes on ASBRs (autonomous system boundary router), where they are injected into OSPF.
HTH
Rolf
12-07-2013 11:08 AM
They are both 3725's running C3725-ADVENTERPRISEK9-M), Version 12.4(15)T14 by the way
12-07-2013 11:32 AM
Hi,
you can't summarize or filter within the same OSPF area because the link-state databases have to be the same on all routers in an area.
You can summarize OSPF internal routes on ABRs (area border router) between areas and external routes on ASBRs (autonomous system boundary router), where they are injected into OSPF.
HTH
Rolf
12-07-2013 11:45 AM
Thank you good sir!
12-07-2013 12:06 PM
You're welcome! Thanks for rating and marking as answered!
12-07-2013 11:16 PM
Hello Matthew,
This doc might help you to understand ospf inter-area summarization
https://supportforums.cisco.com/docs/DOC-27672
Regards,
Ashish Shirkar
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