Route summarization with range from area 0 to a outside area

[hannes1967]

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

[MHM Cisco World]

@hannes1967 
https://www.youtube.com/watch?v=uOq9H1fcOtU

this video exactly your lab. 

take look

[David Ruess]

Hello,

Could you provide the

show run

configurations of all 3 devices?

A couple things to note:

The

NOT-ADVERTISE

keyword will NOT advertise the summary address. If you want it advertised and showing up make sure to take that off

The

area range

command needs to be done in the Area where the routes are originated from, not going to.

Try deleting your

range

commands with the full mask and use / notation if it will let you.

Side note: If there are other connections to these devices where they are getting the same subnet it will use the more specific route. (longest match)

Cisco IOS IP Routing: OSPF Command Reference - OSPF Commands: A through ip ospf demand-circuit [Support] - Cisco

-David

[paul driver]

Hello

---

@hannes1967 wrote:

Is summarization only supported from an area to backbone area?

---

It supported either way:
from the BB area into a non BB area
from non BB area into  BB area

I assume rtr has presence in both areas <ABR>, if so then append a network statment for a network which will be included in the summary and you should be good.

example:
router ospf 2
network 10.4.2.2 0.0.0.0. area 0
network 10.2.2.2 0.0.0.0. area 1
area 0 range 10.4.0.0 255.255.0.0
area 1 range 10.2.0.0 255.255.0.0

[pman · Accepted solution]

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

 

 

[hannes1967]

Hi!

Looks like a solution!

Thank you very much!

I will check with GNS3 simulator tomorrow morning!

regards, Hannes

[hannes1967]

Dear Friends,

now I tested on GNS3 and I have a solution!

Thank you all!

Please see also att image001.png, which is not complete!

My mistakes in due to misunderstanding of OSPF:

I tried to summarize the network 10.4.1.1 which is in area 8!
The summarization I made was in d2 which is an ABR between area 0 and area 1!

If 10.4.1.1 were in area 0, everything would working fine!

So I configured additional networks with loopback interfaces in d4 in area 0!
Then I summarized these networks with range command in d2!

d2#sh run | i ran

 area 0 range 11.0.0.0 255.0.0.0

 area 0 range 12.0.0.0 255.0.0.0




All configs:




d4




interface Loopback0

 ip address 11.4.1.1 255.255.255.255

 ip ospf network point-to-point

!

interface Loopback1

 ip address 11.5.1.1 255.255.255.255

 ip ospf network point-to-point

!

interface Loopback3

 ip address 12.6.1.1 255.255.0.0

!

interface Loopback4

 ip address 10.4.1.1 255.255.255.0

!

interface Loopback5

 ip address 12.7.1.1 255.255.0.0

!

interface FastEthernet0/0

 ip address 1.0.0.2 255.255.255.0

 duplex auto

 speed auto

!

interface FastEthernet0/1

 no ip address

 shutdown 

 duplex auto

 speed auto

!

!

router ospf 2

 log-adjacency-changes

 area 0 range 10.6.0.0 255.255.0.0

 network 1.0.0.0 0.0.0.255 area 0

 network 10.4.1.0 0.0.0.255 area 8

 network 10.5.1.0 0.0.0.255 area 8

 network 10.6.0.0 0.0.255.255 area 0

 network 11.0.0.0 0.255.255.255 area 0

 network 12.0.0.0 0.255.255.255 area 0




d2




interface FastEthernet0/0

 ip address 1.0.0.1 255.255.255.0

 duplex auto

 speed auto

!

interface FastEthernet0/1

 ip address 2.0.0.1 255.255.255.0

 duplex auto

 speed auto

!

!

router ospf 2

 log-adjacency-changes

 area 0 range 11.0.0.0 255.0.0.0

 area 0 range 12.0.0.0 255.0.0.0

 area 1 range 10.2.0.0 255.255.0.0

 area 1 range 10.4.0.0 255.255.0.0 not-advertise

 network 1.0.0.0 0.0.0.255 area 0

 network 2.0.0.0 0.0.0.255 area 1

 network 10.20.0.0 0.0.255.255 area 1




d7




interface Loopback0

 ip address 10.2.1.1 255.255.255.255

!

interface Loopback1

 ip address 10.3.1.1 255.255.255.255

!

interface FastEthernet0/0

 ip address 2.0.0.2 255.255.255.0

 duplex auto

 speed auto

!

interface FastEthernet0/1

 no ip address

 shutdown

 duplex auto

 speed auto

!

!

router ospf 2

 log-adjacency-changes

 network 2.0.0.0 0.0.0.255 area 1

 network 10.2.1.0 0.0.0.255 area 1

 network 10.3.0.0 0.0.255.255 area 1




Routing table d7:




d7#sh ip rou

Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP

       D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area 

       N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2

       E1 - OSPF external type 1, E2 - OSPF external type 2

       i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2

       ia - IS-IS inter area, * - candidate default, U - per-user static route

       o - ODR, P - periodic downloaded static route




Gateway of last resort is not set




     1.0.0.0/24 is subnetted, 1 subnets

O IA    1.0.0.0 [110/2] via 2.0.0.1, 02:10:16, FastEthernet0/0

     2.0.0.0/24 is subnetted, 1 subnets

C       2.0.0.0 is directly connected, FastEthernet0/0

     10.0.0.0/32 is subnetted, 3 subnets

C       10.2.1.1 is directly connected, Loopback0

C       10.3.1.1 is directly connected, Loopback1

O IA    10.4.1.1 [110/3] via 2.0.0.1, 02:10:16, FastEthernet0/0

O IA 11.0.0.0/8 [110/3] via 2.0.0.1, 00:21:14, FastEthernet0/0

O IA 12.0.0.0/8 [110/3] via 2.0.0.1, 01:25:08, FastEthernet0/0

[MHM Cisco World]

Ohh, 
I was think that my solution is not right and there is some thing in commend I share,
anyway glad that your issue is solved, so as I mention the issue you config the area range in wrong ABR.

Good Job friend.

[hannes1967]

Thank you very much!