Redistributing OSPF Summary routes question?

kaynejenkins

I have been stuck on this all morning and not sure if there is a solution. I am trying to redistribute a summarized range of addresses into Eigrp from OSPF.

When I use "area range" cmd on the OSPF rtr advertising the group of loopback addresses, the addresses are not summarized within that OSPF area, this I think is normal.

However those individual loopback addresses arrive at the OSPF ASBR and are still not summarized in the ASBR's routing table. This also I think is normal.

What I am trying to do is ensure these addresses are summarized before or as they enter Eigrp from redistributing on the same ASBR.

If I go onto the Eigrp interface (the area I wish to summarized into) and use the "ip summary-address eigrp" cmd, as these rtes pass onto other Eigrp rtrs they are now given an AD of 90, and lose their External redistributed AD of 170.

My aim is to acheive summarized redist of these loopback addresses into Eigrp from OSPF, but as they pass through the Eigrp AS I want them to keep the External AD of 170 not the new AD of 90 after the "ip summary-address eigrp" cmd.

I have also tried to state the AD of 170 at the end of the cmd. ie....

"ip summary-address eigrp 1 30.0.0.0 255.255.248.0 170"

After applying this cmd the other Eigrp rtrs receive the summarized prefix of 30.0.0.0/21, but still have an AD of 90. The AD put at the end of the cmd of 170 has made no difference.

Is this possible to do? or just a limitation redistribution?

Thanks

kayne

okplaya

Studying route, but I'll take a shot. Could it be that you need to change the network type for the loopbacks?

By default, the network type is LOOPBACK. I believe if you change the network type to Point-Point you could then summarize better.

I wish I could try, but I'm at work right now. Let me know if that works.

kaynejenkins

Thanks for the reply. I changed all the Loopback Interfaces to Ip OSPF Network P2P networks and tried to redist on the ASBR from OSPF into Eigrp. I added the area range address on the OSPF interface on the ASBR and added the Ip summary-address eigrp cmd on the Eigrp interface on the ASBR (including the AD of 170 at the end) still the loopback address get populated through the Eigrp AS as 30.0.0.0/21 (90/metric). As you can see the loopback addresses have been summarized but still do not have the external Eigrp AD of 170 that was stated at the end of the "ip summary-add eigrp" cmd. Even trying this cmd on other Eigrp rtrs within the AS does not change the AD to 170.

Nate--IRL--

I'll have to admit to not knowing the solution to your main question - however note that setting the AD is locally significant - it is not propagated to other eigrp routers. It seems from my quick reading about redistribution and summary routes into eigrp, that Summarising redistributed routes will always be converted to AD 90. I'm not quite sure about the logic for this.

May be relevant -- > Enhanced Interior Gateway Routing Protocol - Cisco Systems

Nate

Zartanasaurus

kaynejenkins wrote: »

When I use "area range" cmd on the OSPF rtr advertising the group of loopback addresses, the addresses are not summarized within that OSPF area, this I think is normal.

Let me give a better explanation here since I have more time.

How many areas do you have in your OSPF topology? Area range works by summarizing routes from an area to the other areas and only works on an ABR. If your ASBR isn't also an ABR, this won't work. What you could do is create a static route for the summary pointing to Null0 and redistribute that into EIGRP.

Also (and I don't think this is the case), if you are summarizing external OSPF routes, you use the summary-address command on the ASBR.

kaynejenkins

yes I am redist from an ASBR OSPF routes into Eigrp.

I have knocked up and attached the topology

Router 3 is performing "area 0 range 30.0.0.0 255.255.248.0", and this summarizes the loops before passing them into OSPF 1 area 1. But had no effect on summarizing them before they were redistributed into Eigrp 1, the loops were redistributed as /32 addresses as viewed in Router 4's route table.

So next I applied " ip summary-address Eigrp 1 30.0.0.0 255.255.248.0 170" cmd on interface fa1/1 on R5 and also on 1/0 on R4, and it seems that this time it worked with R4 receiving a summarised 30.0.0.0/21 AD 170.

Now this is my next problem I would like to understand, after further testing I have found the problem.

I know it is not normal to connect two OSPF Area 0's together but in my previous test lab I did just that. I had the ASBR redist between two OSPF area 0's and it did not work.

Looking at the attached topology, if you changed OSPF 1 Area 1 to OSPF 2 Area 0, (as ive put int brackets on the topology)

so you have removed OSPF 1 Area 1 cmds from R5 and R7, and replaced it with OSPF 2, network 192.168.0.0 area 0.

So now R5 connects two separate OSPF area 0's.

And is still redistributing Eigrp 1 to OSPF 1, for some reason R4 does not receive previous summarised route with the AD of 170 (30.0.0.0/21 AD 170) but instead receives this route 30.0.0.0/21 AD 90.

This route has now been received instead of the previous AD 170 route.

It only dissappeared when R5 connected two different OSPF AS's together, (not redistributing between OSPF AS's) just connected.

So R5 is no longer an ABR since it is no longer connecting areas from the same OSPF AS (which would mean the "area range x.x.x.x" cmd would not work,

It is connecting two different OSPF AS (but not currently redist) and also connecting Eigrp to OSPF.

So why did the 30.0.0.0/21 AD 170 route dissappear from R4?

Since it was an Eigrp cmd in the Eigrp AS....

"ip summary-address Eigrp 1 30.0.0.0 255.255.248.0 170"

how did the OSPF Area change effect the AD of the summary route?

Zartanasaurus

Okay let's see if we can get this straightened out.

kaynejenkins wrote: »

I have knocked up and attached the topology

Router 3 is performing "area 0 range 30.0.0.0 255.255.248.0", and this summarizes the loops before passing them into OSPF 1 area 1. But had no effect on summarizing them before they were redistributed into Eigrp 1, the loops were redistributed as /32 addresses as viewed in Router 4's route table.

You should get getting 5 EX routes on R4. Four for the individual /32 loopbacks and the /21 summary. The fact you aren't seeing the summary in eigrp leads me to believe you are doing the summarization on the wrong router.

You also say R3 is performing the area range command, but from the diagram it looks like R3 is the bottom right and not an ABR? Or am I misreading it because of the small type? The router that should be performing this is the one in the dead center. Looks like it's labeled as R5. Can we get a show ip route ospf/show ip route eigrp for the 3 routers on the right-hand side of the diagram?

NetworkVeteran

Kayne, if you replace all the talkie with "show ip route" and "show run | s router" (your full routing protocol configuration) for each of the routers there'd be a heckuva lot less confusion.

kaynejenkins

yes that was a typing mistake, R5 the router in the middle is performing the area range cmd, I have attached the configs with sho run/sho ip ro for R3/R4/R5 with the configs of R5 connecting OSPF 1 area 0 to OSPF 2 area 0 (but not redist).

And in this setup R4 only has this route 30.0.0.0 [90/261120] in its routing table, despite R5 having "ip summary-address eigrp 1 30.0.0.0 255.255.248.0 170" applied on fa 1/1.

As soon as you put the 192.168.0.0 link between R7 and R5 back to the intiail config in OSPF 1 area 1, so R5 now acts as both ABR and ASBR the summary route with AD 170 returns.

It seems this OSPF area process is affecting the Eigrp ip summary cmd.

Couldnt manage to attach configs file, so just pasted them below.

hostname R4
!
boot-start-marker
boot-end-marker
!
!
no aaa new-model
ip subnet-zero
ip source-route
!
!
!
!
ip cef
no ip domain lookup
ip domain name lab.local
!
!
multilink bundle-name authenticated
!
!
!
!
!
!
!
!
!
!
interface FastEthernet0/0
no ip address
shutdown
duplex half
!
interface FastEthernet1/0
ip address 192.170.0.1 255.255.255.0
speed auto
duplex auto
!
interface FastEthernet1/1
no ip address
shutdown
speed auto
duplex auto
!
router eigrp 1
network 192.170.0.0
no auto-summary
!
ip classless
!
!
no ip http server
no ip http secure-server
!
!
!
!
control-plane
!
!
line con 0
exec-timeout 0 0
privilege level 15
logging synchronous
stopbits 1
line aux 0
exec-timeout 0 0
privilege level 15
logging synchronous
stopbits 1
line vty 0 4
login
!
end




R4#sho ip ro
Codes: L - local, 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, + - replicated route


Gateway of last resort is not set


30.0.0.0/21 is subnetted, 1 subnets
D 30.0.0.0 [90/261120] via 192.170.0.2, 02:21:22, FastEthernet1/0
D EX 192.168.1.0/24 [170/261120] via 192.170.0.2, 02:31:34, FastEthernet1/0
192.170.0.0/24 is variably subnetted, 2 subnets, 2 masks
C 192.170.0.0/24 is directly connected, FastEthernet1/0
L 192.170.0.1/32 is directly connected, FastEthernet1/0
R4#









hostname R3
!
boot-start-marker
boot-end-marker
!
!
no aaa new-model
ip subnet-zero
ip source-route
!
!
!
!
ip cef
no ip domain lookup
ip domain name lab.local
!
!
multilink bundle-name authenticated
!
!
!
!
!
!
!
!
!
!
interface Loopback0
ip address 30.0.0.1 255.255.255.255
!
interface Loopback1
ip address 30.0.1.1 255.255.255.255
!
interface Loopback2
ip address 30.0.2.1 255.255.255.255
!
interface Loopback3
ip address 30.0.3.1 255.255.255.255
!
interface FastEthernet0/0
no ip address
shutdown
duplex half
!
interface FastEthernet1/0
ip address 192.168.1.2 255.255.255.0
speed auto
duplex auto
!
interface FastEthernet1/1
no ip address
shutdown
speed auto
duplex auto
!
router ospf 1
router-id 3.3.3.3
log-adjacency-changes
network 30.0.0.0 0.0.255.255 area 0
network 192.168.1.0 0.0.0.255 area 0
!
ip classless
!
!
no ip http server
no ip http secure-server
!
!
!
!
control-plane
!
!
line con 0
exec-timeout 0 0
privilege level 15
logging synchronous
stopbits 1
line aux 0
exec-timeout 0 0
privilege level 15
logging synchronous
stopbits 1
line vty 0 4
login
!
end


R3#




R3#sho ip ro
Codes: L - local, 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, + - replicated route


Gateway of last resort is not set


30.0.0.0/8 is variably subnetted, 5 subnets, 2 masks
O E1 30.0.0.0/21 [110/21] via 192.168.1.1, 02:24:12, FastEthernet1/0
C 30.0.0.1/32 is directly connected, Loopback0
C 30.0.1.1/32 is directly connected, Loopback1
C 30.0.2.1/32 is directly connected, Loopback2
C 30.0.3.1/32 is directly connected, Loopback3
192.168.1.0/24 is variably subnetted, 2 subnets, 2 masks
C 192.168.1.0/24 is directly connected, FastEthernet1/0
L 192.168.1.2/32 is directly connected, FastEthernet1/0
O E1 192.170.0.0/24 [110/21] via 192.168.1.1, 02:33:23, FastEthernet1/0
R3#






hostname R5
!
boot-start-marker
boot-end-marker
!
!
no aaa new-model
ip subnet-zero
ip source-route
!
!
!
!
ip cef
no ip domain lookup
ip domain name lab.local
!
!
multilink bundle-name authenticated
!
!
!
!
!
!
!
!
!
!
interface FastEthernet0/0
no ip address
shutdown
duplex half
!
interface FastEthernet1/0
ip address 192.168.0.2 255.255.255.0
speed auto
duplex auto
!
interface FastEthernet1/1
ip address 192.170.0.2 255.255.255.0
ip summary-address eigrp 1 30.0.0.0 255.255.248.0 170
speed auto
duplex auto
!
interface FastEthernet2/0
ip address 192.168.1.1 255.255.255.0
speed auto
duplex auto
!
interface FastEthernet2/1
no ip address
shutdown
speed auto
duplex auto
!
router eigrp 1
network 192.170.0.0
no auto-summary
redistribute ospf 1 metric 10000 10 255 1 1500
!
router ospf 1
router-id 5.5.5.5
log-adjacency-changes
area 0 range 30.0.0.0 255.255.248.0
redistribute eigrp 1 metric 20 metric-type 1 subnets
network 192.168.1.0 0.0.0.255 area 0
!
router ospf 2
log-adjacency-changes
network 192.168.0.0 0.0.0.255 area 0
!
ip classless
!
!
no ip http server
no ip http secure-server
!
!
!
!
control-plane
!
!
line con 0
exec-timeout 0 0
privilege level 15
logging synchronous
stopbits 1
line aux 0
exec-timeout 0 0
privilege level 15
logging synchronous
stopbits 1
line vty 0 4
login
!
end


R5#sho ip ro
Codes: L - local, 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, + - replicated route


Gateway of last resort is not set


30.0.0.0/8 is variably subnetted, 5 subnets, 2 masks
D 30.0.0.0/21 is a summary, 02:24:42, Null0
O 30.0.0.1/32 [110/2] via 192.168.1.2, 02:24:42, FastEthernet2/0
O 30.0.1.1/32 [110/2] via 192.168.1.2, 02:24:42, FastEthernet2/0
O 30.0.2.1/32 [110/2] via 192.168.1.2, 02:24:42, FastEthernet2/0
O 30.0.3.1/32 [110/2] via 192.168.1.2, 02:24:42, FastEthernet2/0
192.168.0.0/24 is variably subnetted, 2 subnets, 2 masks
C 192.168.0.0/24 is directly connected, FastEthernet1/0
L 192.168.0.2/32 is directly connected, FastEthernet1/0
192.168.1.0/24 is variably subnetted, 2 subnets, 2 masks
C 192.168.1.0/24 is directly connected, FastEthernet2/0
L 192.168.1.1/32 is directly connected, FastEthernet2/0
192.170.0.0/24 is variably subnetted, 2 subnets, 2 masks
C 192.170.0.0/24 is directly connected, FastEthernet1/1
L 192.170.0.2/32 is directly connected, FastEthernet1/1
R5#

MrXpert

Can you not just use the summary-address command within the OSPF process on the ASBR? this is how I do it. Make sure the routes you want redistributed into EIGRP are actually in the ASBR's routing table.
The area range command will not summarize redistributed routes. It only works for Inter area routes.

Nate--IRL--

Isn't Summary-address only useful when redistributing routes into OSPF? Or will it summarise routes present in the current area also? EDIT:- No it won't - only summarizes external routes into OSPF

Nate

kaynejenkins

Mrxpert, thanks for your reply. I tried what you said, however you cannot apply the Eigrp "ip summary-address Eigrp 1 x.x.x.x 170"
cmd on the OSPF interface on the ASBR. It can be put on the interface but has no effect in summarizing routes into the Eigrp process.

NetworkVeteran

Kayne, the reason your configuration isn't working is actually quite simple---you're using the "area range" command on R5, but R5 is not an Area Border Router! Therefore, OSPF performs no summarization. You perform the summarization in EIGRP, and EIGRP rightly notes the summary route was originated within (is internal to) the EIGRP domain. Here are a few fixes..

Solution #1: Make R5 an Area Border Router, by adding an interface in a different area.

R2#sh ip route ospf
30.0.0.0/32 is subnetted, 3 subnets
O 30.0.2.1 [110/11] via 1.0.0.1, 00:00:44, FastEthernet0/0
O 30.0.1.1 [110/11] via 1.0.0.1, 00:00:44, FastEthernet0/0
O 30.0.0.1 [110/11] via 1.0.0.1, 00:00:44, FastEthernet0/0
R2#conf t
Enter configuration commands, one per line. End with CNTL/Z.
R2(config)#int loo5
R2(config-if)#ip ospf 1 area 1
R2(config-if)#end
R2#sh ip route ospf
*Mar 1 00:30:37.743: %SYS-5-CONFIG_I: Configured from console by console
R2#sh ip route ospf
30.0.0.0/8 is variably subnetted, 4 subnets, 2 masks
O 30.0.2.1/32 [110/11] via 1.0.0.1, 00:00:02, FastEthernet0/0
O 30.0.1.1/32 [110/11] via 1.0.0.1, 00:00:02, FastEthernet0/0
O 30.0.0.0/8 is a summary, 00:00:02, Null0
O 30.0.0.1/32 [110/11] via 1.0.0.1, 00:00:02, FastEthernet0/0

Solution #2: Use a static route to perform your summarization

"ip route 30.0.0.0 255.255.248.0 null 0
redistribute static metric 100000 1000 128 128 1500"

Solution #3: (Subtle) Use a route-map to gives external routes and summarized external routes a special tag:

route-map RM_SYMPATHY
match ip address 1
set tag 666

NetworkVeteran

kayne wrote:

so you have removed OSPF 1 Area 1 cmds from R5 and R7, and replaced it with OSPF 2, network 192.168.0.0 area 0... how did the OSPF Area change effect the AD of the summary route?

Quite simply, this change converts R5 from an ABR into a non-ABR. I see Zataranasaurus and I came to the same conclusion. Also, as Nate points out, AD is only locally significant.

kaynejenkins

Thanks for clearing that up. I ran these changes and it now works as you have said, cheers.