Solved: Re: Route summarization with range from area 0 to a outside area

hannes1967 · ‎06-08-2022

Dear friends,

I need to summarize routes from the backbone area to connected areas!

The line in the config of the ABR looks like:

router ospf 2

area 0 range 10.4.0.0 255.255.0.0

area 1 range 10.2.0.0 255.255.0.0

The routing table on a router in area 1 looks like this:

d7-2610xm-TelAnl#sh ip route os

     1.0.0.0/24 is subnetted, 1 subnets

O IA    1.0.0.0 [110/11] via 2.0.0.1, 00:18:31, FastEthernet0/0

     10.0.0.0/32 is subnetted, 2 subnets

O IA    10.4.1.1 [110/12] via 2.0.0.1, 00:18:31, FastEthernet0/0




No summary 10.4.0.0/16

Is summarization only supported from an area to backbone area?
I found some examples in the net from cisco training sites, which show that summary should als work from backbone area to outside!

regards, Hannes

pman · ‎06-08-2022

Hi,

summary example:

vIOS3

interface GigabitEthernet0/0
ip address 1.3.1.3 255.255.255.0
ip ospf 1 area 10
!
interface Loopback10
ip address 10.10.10.10 255.255.255.0
ip ospf 1 area 0
!
interface Loopback20
ip address 10.10.20.10 255.255.255.0
ip ospf 1 area 0
!
router ospf 1
area 0 range 10.10.0.0 255.255.0.0




vIOS1

interface GigabitEthernet0/0
ip address 1.3.1.1 255.255.255.0
ip ospf 1 area 10





vIOS1#show ip route

         10.0.0.0/16 is subnetted, 1 subnets
O IA       10.10.0.0 [110/2] via 1.3.1.3, 00:12:41, GigabitEthernet0/0

View solution in original post