From: Bit Gossip (bit.gossip@chello.nl)
Date: Wed May 23 2007 - 16:21:47 ART
Hi Victor, group
I understand the issue with the FA. But I think that it has nothing to do
with my question to the group which is why out of the 2 ABRs, R2 and R3,
only R2 translates the N2 to E2. See my previous posting.
I could only find the following explanation
``Note: With the fix of Cisco bug ID CSCdp72526 ( registered customers only)
, OSPF does not generate a type-5 link-state advertisement (LSA) of an
overlapped external network.``
http://www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a008009405a.shtml
Any enlightening welcome!
Bit
----- Original Message -----
From: "Victor Cappuccio" <victor@ccbootcamp.com>
To: "Bit Gossip" <bit.gossip@chello.nl>; "Ivan" <ivan@iip.net>;
<ccielab@groupstudy.com>
Sent: Wednesday, May 23, 2007 6:11 PM
Subject: RE: NSSA FA Supression
> If I may add
>
> SW1#show ip ospf database external 2.2.2.0
>
> OSPF Router with ID (9.9.9.9) (Process ID 1)
>
> Type-5 AS External Link States
>
> Routing Bit Set on this LSA
> LS age: 58
> Options: (No TOS-capability, DC)
> LS Type: AS External Link
> Link State ID: 2.2.2.0 (External Network Number )
> Advertising Router: 4.4.4.4
> LS Seq Number: 80000001
> Checksum: 0xAC5A
> Length: 36
> Network Mask: /24
> Metric Type: 2 (Larger than any link state path)
> TOS: 0
> Metric: 20
> Forward Address: 192.168.24.2
> External Route Tag: 0
>
> Now If you do not know about 192.168.24.2, This shows us the forwarding
> address for this external route
>
> SW1#show ip route 192.168.24.2
> % Network not in table
>
> SW1#show ip ospf neighbor
>
> Neighbor ID Pri State Dead Time Address
> Interface
> 4.4.4.4 1 FULL/BDR 00:00:32 192.168.14.4 Vlan14
> 1.1.1.1 255 FULL/DR 00:00:37 192.168.100.1
> Vlan100
> 10.10.10.10 1 FULL/BDR 00:00:36 192.168.100.10
> Vlan100
>
> SW1#show ip ospf database
>
> OSPF Router with ID (150.150.0.1) (Process ID 100)
>
> OSPF Router with ID (9.9.9.9) (Process ID 1)
>
> Router Link States (Area 0)
>
> Link ID ADV Router Age Seq# Checksum Link
> count
> 1.1.1.1 1.1.1.1 86 0x80000142 0x00BB4E 4
> 4.4.4.4 4.4.4.4 20 0x80000005 0x00EA1B 1
> 6.6.6.6 6.6.6.6 897 0x8000012B 0x005A47 3
> 9.9.9.9 9.9.9.9 25 0x80000143 0x006822 4
> 10.10.10.10 10.10.10.10 87 0x8000002B 0x00766C 2
>
> Net Link States (Area 0)
>
> Link ID ADV Router Age Seq# Checksum
> 192.168.14.10 9.9.9.9 26 0x80000001 0x00DB84
> 192.168.100.1 1.1.1.1 70 0x80000002 0x00F71A
>
> Type-5 AS External Link States
>
> Link ID ADV Router Age Seq# Checksum Tag
> 2.2.2.0 4.4.4.4 16 0x80000001 0x00AC5A 0
>
> Looking at the OSPF External database
>
> SW1#show ip ospf database external 2.2.2.0
>
> OSPF Router with ID (150.150.0.1) (Process ID 100)
>
> OSPF Router with ID (9.9.9.9) (Process ID 1)
>
> Type-5 AS External Link States
>
> LS age: 23
> Options: (No TOS-capability, DC)
> LS Type: AS External Link
> Link State ID: 2.2.2.0 (External Network Number )
> Advertising Router: 4.4.4.4
> LS Seq Number: 80000001
> Checksum: 0xAC5A
> Length: 36
> Network Mask: /24
> Metric Type: 2 (Larger than any link state path)
> TOS: 0
> Metric: 20
> Forward Address: 192.168.24.2
> External Route Tag: 0
>
> SW1#show ip route 192.168.24.0
> % Network not in table
> SW1#ping 2.2.2.2
>
> Type escape sequence to abort.
> Sending 5, 100-byte ICMP Echos to 2.2.2.2, timeout is 2 seconds:
> .....
> Success rate is 0 percent (0/5)
> SW1#
> RTR-TS1#4
> [Resuming connection 4 to R4 ... ]
>
> *Mar 2 01:09:09.225: %OSPF-5-ADJCHG: Process 100, Nbr 2.2.2.2 on
> Serial0.42 from LOADING to FULL, Lo
> R4(config-router)#router ospf 100
> R4(config-router)#
> R4(config-router)#area 42 nssa translate type7 suppress-fa
> R4(config-router)#
> RTR-TS1#2
> [Resuming connection 2 to sw1 ... ]
>
> SW1#show ip ospf database external 2.2.2.0
>
> OSPF Router with ID (150.150.0.1) (Process ID 100)
>
> OSPF Router with ID (9.9.9.9) (Process ID 1)
>
> Type-5 AS External Link States
>
> Routing Bit Set on this LSA
> LS age: 8
> Options: (No TOS-capability, DC)
> LS Type: AS External Link
> Link State ID: 2.2.2.0 (External Network Number )
> Advertising Router: 4.4.4.4
> LS Seq Number: 80000002
> Checksum: 0x2564
> Length: 36
> Network Mask: /24
> Metric Type: 2 (Larger than any link state path)
> TOS: 0
> Metric: 20
> Forward Address: 0.0.0.0 ---------- Forwarding address modified
> External Route Tag: 0
>
> SW1#ping 2.2.2.2
>
> Type escape sequence to abort.
> Sending 5, 100-byte ICMP Echos to 2.2.2.2, timeout is 2 seconds:
> !!!!!
> Success rate is 100 percent (5/5), round-trip min/avg/max = 59/62/67 ms
> SW1#
>
> SW1#show ip route 2.2.2.2
> Routing entry for 2.2.2.0/24
> Known via "ospf 1", distance 110, metric 20, type extern 2, forward
> metric 1
> Last update from 192.168.14.4 on Vlan14, 00:02:09 ago
> Routing Descriptor Blocks:
> * 192.168.14.4, from 4.4.4.4, 00:02:09 ago, via Vlan14
> Route metric is 20, traffic share count is 1
>
> SW1#show ip route 0.0.0.0
> % Network not in table
> SW1#
>
> Another example of this could be
> http://www.groupstudy.com/archives/ccielab/200508/msg01333.html
>
>
> thanks,
> Victor Cappuccio.-
>
> - CCSI# 31452
> Network Learning Inc - A Cisco Sponsored Organization (SO) YES! We take
> Cisco Learning credits!
> victor@ccbootcamp.com
> http://www.ccbootcamp.com (Cisco Training and Rental Racks)
> http://www.ccbootcamp.com/groupstudy.html (groupstudy member discounts!)
> Voice: 702-968-5100
> FAX: 702-446-8012
>
>
>
> -----Original Message-----
> From: nobody@groupstudy.com on behalf of Bit Gossip
> Sent: Wed 5/23/2007 8:54
> To: Ivan; ccielab@groupstudy.com
> Subject: Re: NSSA FA Supression
>
> 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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>
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