From: Bit Gossip (bit.gossip@chello.nl)
Date: Wed May 23 2007 - 12:54:10 ART
Hi Ivan, group,
I have labbed initial Cagri setup with R2 and R3 ABRs between nssa area and
area 0. Indeed only one ABR, in my case R2, translates the N2 into E2. I
still don't get that! Why R3 doesn't translate?
Thanks,
Bit.
R2#show ip route ospf
1.0.0.0/24 is subnetted, 5 subnets
O 1.1.13.0 [110/845] via 1.1.12.1, 00:05:34, Serial4/0.12
O 1.1.34.0 [110/128] via 1.1.24.4, 19:42:27, Serial4/0.24
4.0.0.0/24 is subnetted, 1 subnets
O N2 4.4.4.0 [110/20] via 1.1.24.4, 00:05:34, Serial4/0.24
R3#show ip route ospf
1.0.0.0/24 is subnetted, 5 subnets
O 1.1.12.0 [110/845] via 1.1.13.1, 00:05:57, Serial4/0.13
O 1.1.24.0 [110/128] via 1.1.34.4, 19:42:50, Serial4/0.34
4.0.0.0/24 is subnetted, 1 subnets
O E2 4.4.4.0 [110/20] via 1.1.34.4, 00:05:57, Serial4/0.34
~~~~~~~~~~~~~~~~~~~~~~R1
interface Serial0/0.12 point-to-point
ip address 1.1.12.1 255.255.255.0
frame-relay interface-dlci 102
!
interface Serial0/0.13 point-to-point
ip address 1.1.13.1 255.255.255.0
frame-relay interface-dlci 103
!
!
router ospf 1
router-id 1.1.1.1
network 1.1.12.1 0.0.0.0 area 0
network 1.1.13.1 0.0.0.0 area 0
~~~~~~~~~~~~~~~~~~~~~~~~R2
interface Serial4/0.12 point-to-point
ip address 1.1.12.2 255.255.255.0
frame-relay interface-dlci 201
!
interface Serial4/0.24 point-to-point
ip address 1.1.24.2 255.255.255.0
frame-relay interface-dlci 204
!
interface Serial4/1
ip address 1.1.23.2 255.255.255.0
serial restart-delay 0
!
router ospf 1
area 1 nssa
network 1.1.12.2 0.0.0.0 area 0
network 1.1.23.2 0.0.0.0 area 0
network 1.1.24.2 0.0.0.0 area 1
~~~~~~~~~~~~~~~~~~~~~~~~R3
interface Serial4/0.13 point-to-point
ip address 1.1.13.3 255.255.255.0
frame-relay interface-dlci 301
!
interface Serial4/0.34 point-to-point
ip address 1.1.34.3 255.255.255.0
frame-relay interface-dlci 304
!
interface Serial4/3
ip address 1.1.23.3 255.255.255.0
serial restart-delay 0
!
router ospf 1
area 1 nssa
network 1.1.13.3 0.0.0.0 area 0
network 1.1.23.1 0.0.0.0 area 0
network 1.1.34.3 0.0.0.0 area 1
!
~~~~~~~~~~~~~~~~~~~~~~~~R4
interface Loopback0
ip address 4.4.4.4 255.255.255.0
!
interface Serial0/0.24 point-to-point
ip address 1.1.24.4 255.255.255.0
frame-relay interface-dlci 402
!
interface Serial0/0.34 point-to-point
ip address 1.1.34.4 255.255.255.0
frame-relay interface-dlci 403
!
router ospf 1
area 1 nssa
redistribute connected subnets
network 1.1.24.4 0.0.0.0 area 1
network 1.1.34.4 0.0.0.0 area 1
!
----- Original Message -----
From: "Ivan" <ivan@iip.net>
To: <ccielab@groupstudy.com>; "Cagri Yucel" <cyucel@gmail.com>
Sent: Monday, May 14, 2007 9:09 AM
Subject: Re: NSSA FA Supression
> suppress fa is used to manage Forward Addres in the OSPF LSA. This feature
> can't converse type of route.
>
>
>
>
>
>
>
> Please take some time and look at this config
>
>
> area 1 (NSSA) Area 0
> R1 --------------------- R2 ------------------- R3
> X.X.12.0/30 X.X.23.0/30
>
> Step1:
> ######
> R1:
> redistribute Loopback0 (1.1.1.1)
>
> Verify Result
> ##############
> in R3:
> show ip route will show
> 1.1.1.0/24 as E2 route.
> X.X.12.0/30 as O IA route
> ************************************************************
> Step2:
> ######
> Suppress Area 1 route X.X.12.0/24 in Area 0
> ###########################################
> R2:
> router ospf 1
> area 1 range X.X.12.0 255.255.255.0 no-advertise
>
> Verify in R3:
> show ip route
> you will not see both the routes X.X.12.0/30 and 1.1.1.0/24
>
> R3#show ip ospf database external
> OSPF Router with ID (3.3.3.3) (Process ID 1)
> Type-5 AS External Link States
> Routing Bit Set on this LSA
> LS age: 168
> Options: (No TOS-capability, DC)
> LS Type: AS External Link
> Link State ID: 1.1.1.0 (External Network Number )
> Advertising Router: 1.1.1.1
> LS Seq Number: 80000001
> Checksum: 0x38F0
> Length: 36
> Network Mask: /24
> Metric Type: 2 (Larger than any link state path)
> TOS: 0
> Metric: 20
> Forward Address: 1.1.12.1 <-----------------------------
> External Route Tag: 0
> Note:
> you can see above that the forwarding address 1.1.12.1 for the
> redistributed
> route 1.1.1.0.
> And we filtered the X.X.12.0 from ABR (R2).
> Because R3 does not have route to reach X.X.12.1, it can not populate
> 1.1.1.1
> in R3 Routing table.
>
> **********************************************************************************
> Step3:
> ######
> NSSA forwarding address suppression
> ###################################
> R2:
> router ospf 1
> area 1 nssa translate type7 suppress-fa
> Verify in R3
>
> R3#show ip ospf database external
> OSPF Router with ID (3.3.3.3) (Process ID 1)
> Type-5 AS External Link States
> Routing Bit Set on this LSA
> LS age: 6
> Options: (No TOS-capability, DC)
> LS Type: AS External Link
> Link State ID: 1.1.1.0 (External Network Number )
> Advertising Router: 1.1.1.1
> LS Seq Number: 80000002
> Checksum: 0x61D6
> Length: 36
> Network Mask: /24
> Metric Type: 2 (Larger than any link state path)
> TOS: 0
> Metric: 20
> Forward Address: 0.0.0.0 <-----------------------------
> External Route Tag: 0
>
> Note: Now the forwarding address is 0.0.0.0 which is nothing but the
> border-router. Now the router knows how to reach the border-router
> which is X.X.23.2, it populates 1.1.1.0/24 in the routing table.
>
> R3#show ip ospf border-routers
> OSPF Process 1 internal Routing Table
> Codes: i - Intra-area route, I - Inter-area route
>
> i 2.2.2.2 [647] via 1.1.23.2, Serial1/2, ABR/ASBR, Area 3, SPF 117
>
>
>
>
>
>
>
>
>
>
> On Sunday 13 May 2007 17:32, Cagri Yucel wrote:
>> I managed to solve this question but no idea how it works, I'll be glad
>> if
>> someone enlighten me on this issue
>>
>> R2
>>
>> R1 0 10 R4
>>
>> R3
>>
>> Sorry for dodgy diagram, R1 connected to R2 and R3. R4 connected to R2
>> and
>> R3 and there is a link between R2 and R3.
>> Area 10 is NSSA
>> R4 redistribute one of its loopback
>>
>> Now, this route seems as N2 on R3 and E2 on R2 (depending who is doing
>> the
>> 7to5 conversion)
>>
>> Question asking to have it as N2 on both.
>>
>> When I put area 30 nssa translate type-7 suppress-fa
>> on the router doing conversion I managed to achieve N2 on both routers.
>>
>> What is the idea behind ?
>>
>> Many thanks
>
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This archive was generated by hypermail 2.1.4 : Fri Jun 01 2007 - 06:55:21 ART