OSPF neighborship can't form on ADSL - Page 2

Wassim Aouadi · ‎09-01-2010

Hi,

I have an issue with OSPF on ADSL interfaces. It seems that my router's interface can't "see" the provider's ADSL interface during DR elections. I checked the configuration and it is the same on other routers in my company.

Please have a look at the files.

Giuseppe Larosa · ‎09-03-2010

Hello Peter,

I may be wrong but at the beginning there was a point-to-point ATM subinterface, then later we have seen the enc failed in debug ip packet detail 199.

Now, at least local node can send OSPF unicast hellos on the ATM PVC but no OSPF message is received from SP router.

if ping works there is no encapsulation mismatch, and so at this point SP router may be missing a neighbor command under OSPF process (even if this shouldn't be strictly necessary to have on both ends or not ?)

We know also that the other branch routers sees the SP router as OSPF neighbor

Hope to help

Giuseppe

Peter Paluch · ‎09-03-2010

Hello Giuseppe,

Thank you very much for your thoughts. A few comments:

I may be wrong but at the beginning there was a point-to-point ATM
subinterface, then later we have seen the enc failed in debug ip packet
detail 199.

Now, at least local node can send OSPF unicast hellos on the ATM PVC but no OSPF message is received from SP router.

Actually, at the beginning, the state was just as it is now. The spoke router was configured using BVI interface and it was able to ping the ISP but the OSPF did not come up. Only on my insistence, Wassim converted the configuration into a point-to-point ATM configuration and it, understandably, did not work at all, so Wassim reverted the configuration back to the BVI.

if ping works there is no encapsulation mismatch, and so at this point
SP router may be missing a neighbor command under OSPF process (even if
this shouldn't be  strictly necessary to have on both ends or not ?)

Quite correct. The ping works so there's no encap mismatch, and the ISP routers is not required to have this particular neighbor defined manually (it is sufficient for a spoke router to have its neighbor defined statically).

Any idea? Without knowing more from the ISP I do not see any problem on the spoke router.

Best regards,

Peter

Wassim Aouadi · ‎09-03-2010

Giuseppe, I issued "protocol bridge broadcast" under atm interface but nothing seems to change.

Here's the output of the latest debug:

*Sep 3 07:35:19.072 UTC: OSPF: Sending poll to 0.0.0.0 address 192.168.200.17 on BVI1
*Sep 3 07:35:19.072 UTC: OSPF: Send hello to 192.168.200.17 area 2 on BVI1 from 192.168.200.19
TNRTAGCS01008(config-if-atm-vc)#
TNRTAGCS01008(config-if-atm-vc)#
*Sep 3 07:37:19.072 UTC: OSPF: Sending poll to 0.0.0.0 address 192.168.200.17 on BVI1
*Sep 3 07:37:19.072 UTC: OSPF: Send hello to 192.168.200.17 area 2 on BVI1 from 192.168.200.19
TNRTAGCS01008(config-if-atm-vc)#
TNRTAGCS01008(config-if-atm-vc)#
*Sep 3 07:39:19.072 UTC: OSPF: Sending poll to 0.0.0.0 address 192.168.200.17 on BVI1
*Sep 3 07:39:19.072 UTC: OSPF: Send hello to 192.168.200.17 area 2 on BVI1 from 192.168.200.19
TNRTAGCS01008(config-if-atm-vc)#
*Sep 3 07:41:19.072 UTC: OSPF: Sending poll to 0.0.0.0 address 192.168.200.17 on BVI1
*Sep 3 07:41:19.072 UTC: OSPF: Send hello to 192.168.200.17 area 2 on BVI1 from 192.168.200.19
TNRTAGCS01008(config-if-atm-vc)#
*Sep 3 07:43:13.772 UTC: OSPF: Build router LSA for area 2, router ID 192.168.200.19, seq 0x80000D8B, process 1
TNRTAGCS01008(config-if-atm-vc)#
*Sep 3 07:43:19.072 UTC: OSPF: Sending poll to 0.0.0.0 address 192.168.200.17 on BVI1
*Sep 3 07:43:19.072 UTC: OSPF: Send hello to 192.168.200.17 area 2 on BVI1 from 192.168.200.19
TNRTAGCS01008(config-if-atm-vc)#
TNRTAGCS01008(config-if-atm-vc)#
TNRTAGCS01008(config-if-atm-vc)#
*Sep 3 07:45:19.072 UTC: OSPF: Sending poll to 0.0.0.0 address 192.168.200.17 on BVI1
*Sep 3 07:45:19.072 UTC: OSPF: Send hello to 192.168.200.17 area 2 on BVI1 from 192.168.200.19
TNRTAGCS01008(config-if-atm-vc)#
*Sep 3 07:47:19.072 UTC: OSPF: Sending poll to 0.0.0.0 address 192.168.200.17 on BVI1
*Sep 3 07:47:19.072 UTC: OSPF: Send hello to 192.168.200.17 area 2 on BVI1 from 192.168.200.19
TNRTAGCS01008(config-if-atm-vc)#
*Sep 3 07:49:19.072 UTC: OSPF: Sending poll to 0.0.0.0 address 192.168.200.17 on BVI1
*Sep 3 07:49:19.072 UTC: OSPF: Send hello to 192.168.200.17 area 2 on BVI1 from 192.168.200.19
TNRTAGCS01008(config-if-atm-vc)#
*Sep 3 07:51:19.072 UTC: OSPF: Sending poll to 0.0.0.0 address 192.168.200.17 on BVI1
*Sep 3 07:51:19.072 UTC: OSPF: Send hello to 192.168.200.17 area 2 on BVI1 from 192.168.200.19
TNRTAGCS01008(config-if-atm-vc)#
*Sep 3 07:53:19.072 UTC: OSPF: Sending poll to 0.0.0.0 address 192.168.200.17 on BVI1
*Sep 3 07:53:19.072 UTC: OSPF: Send hello to 192.168.200.17 area 2 on BVI1 from 192.168.200.19
TNRTAGCS01008(config-if-atm-vc)#
*Sep 3 07:55:19.072 UTC: OSPF: Sending poll to 0.0.0.0 address 192.168.200.17 on BVI1
*Sep 3 07:55:19.072 UTC: OSPF: Send hello to 192.168.200.17 area 2 on BVI1 from 192.168.200.19
TNRTAGCS01008(config-if-atm-vc)#
TNRTAGCS01008(config-if-atm-vc)#
*Sep 3 07:57:19.072 UTC: OSPF: Sending poll to 0.0.0.0 address 192.168.200.17 on BVI1
*Sep 3 07:57:19.072 UTC: OSPF: Send hello to 192.168.200.17 area 2 on BVI1 from 192.168.200.19
TNRTAGCS01008(config-if-atm-vc)#
*Sep 3 07:59:19.072 UTC: OSPF: Sending poll to 0.0.0.0 address 192.168.200.17 on BVI1
*Sep 3 07:59:19.072 UTC: OSPF: Send hello to 192.168.200.17 area 2 on BVI1 from 192.168.200.19
TNRTAGCS01008(config-if-atm-vc)#
*Sep 3 08:01:19.072 UTC: OSPF: Sending poll to 0.0.0.0 address 192.168.200.17 on BVI1
*Sep 3 08:01:19.072 UTC: OSPF: Send hello to 192.168.200.17 area 2 on BVI1 from 192.168.200.19
TNRTAGCS01008(config-if-atm-vc)#
TNRTAGCS01008(config-if-atm-vc)#
*Sep 3 08:03:19.072 UTC: OSPF: Sending poll to 0.0.0.0 address 192.168.200.17 on BVI1
*Sep 3 08:03:19.072 UTC: OSPF: Send hello to 192.168.200.17 area 2 on BVI1 from 192.168.200.19
TNRTAGCS01008(config-if-atm-vc)#

and here's a "show ip arp" on the router:

TNRTAGCS01008(config)#do sh ip arp
Protocol Address          Age (min) Hardware Addr   Type   Interface
Internet 10.101.4.130          223   18a9.0532.5cc3 ARPA   FastEthernet0/0.1100
Internet 10.101.4.131           51   f4ce.4605.8fb1 ARPA   FastEthernet0/0.1100
Internet 10.101.4.158            -   0023.eb79.aab8 ARPA   FastEthernet0/0.1100
Internet 10.101.4.174            -   0023.eb79.aab8 ARPA   FastEthernet0/0.1200
Internet 10.101.4.190            -   0023.eb79.aab8 ARPA   FastEthernet0/0.1300
Internet 10.101.4.248           78   0064.40ee.e741 ARPA   FastEthernet0/0.1900
Internet 10.101.4.254            -   0023.eb79.aab8 ARPA   FastEthernet0/0.1900
Internet 22.101.4.129           18   9caf.caff.5867 ARPA   FastEthernet0/0.2222
Internet 22.101.4.254            -   0023.eb79.aab8 ARPA   FastEthernet0/0.2222
Internet 192.168.100.33        235   001b.0de6.ea40 ARPA   FastEthernet0/1
Internet 192.168.100.34          -   0023.eb79.aab9 ARPA   FastEthernet0/1
Internet 192.168.200.17        104   0090.1a42.1ebc ARPA   BVI1
Internet 192.168.200.18        145   0000.0c55.7770 ARPA   BVI1
Internet 192.168.200.19          -   0000.0ce8.2ee0 ARPA   BVI1

Peter Paluch · ‎09-03-2010

Wassim,

Did your ISP agree to use these commands as I suggested earlier?

debug condition interface bvi1
debug ip ospf events
debug ip ospf adj

(The ISP shall substitute the "bvi1" with his own interface that provides bridging for you).

Best regards,

Peter

Wassim Aouadi · ‎09-03-2010

I'm waiting for the ISP to do it. I'll keep you informed.

Thanks

francisco_1 · ‎09-02-2010

...............

francisco_1 · ‎09-02-2010

Have you tried using ip "ospf mtu-ignore"

Can you post show "ip ospf interface bvi1" on both sides and post the full config on both sides.

Post deb ip ospf adj also.

Francisco.

Peter Paluch · ‎09-02-2010

Hello Francisco,

Thank you for your suggestions. Please read the the entire thread carefully - most of your questions are already answered or not applicable at this point.

Best regards,

Peter

Wassim Aouadi · ‎09-02-2010

Francisco,

I don't think it's a matter of MTU. If it was, debugs would show me "mtu mismatch".

TNRTAGCS01008#show ip ospf int bvi1
BVI1 is up, line protocol is up
Internet Address 192.168.200.19/28, Area 2
Process ID 1, Router ID 192.168.200.19, Network Type NON_BROADCAST, Cost: 333
Transmit Delay is 1 sec, State DR, Priority 100
Designated Router (ID) 192.168.200.19, Interface address 192.168.200.19
No backup designated router on this network
Timer intervals configured, Hello 30, Dead 120, Wait 120, Retransmit 5
oob-resync timeout 120
Hello due in 00:00:22
Supports Link-local Signaling (LLS)
Cisco NSF helper support enabled
IETF NSF helper support enabled
Index 7/7, flood queue length 0
Next 0x0(0)/0x0(0)
Last flood scan length is 0, maximum is 0
Last flood scan time is 0 msec, maximum is 0 msec
Neighbor Count is 0, Adjacent neighbor count is 0
Suppress hello for 0 neighbor(s)
TNRTAGCS01008#

for OSPF debugs, note that I did a shut/no shut on the bvi interface. And I can't afford to post the ISP router config, but I guess their interface has default OSPF priority value. And it is already a DR with another branch router of the company.

TNRTAGCS01002#sh ip ospf neigh

Neighbor ID Pri State Dead Time Address Interface
192.168.200.17 1 FULL/DR 00:01:56 192.168.200.17 BVI1

Peter Paluch · ‎09-02-2010

Francisco,

You are more than welcome to help! My original reply to your post here was based on the facts that:

You suggested using the ip ospf mtu-ignore - there's no reason for that at this point as the OSPF routers do not even see themselves so they cannot be in the ExStart/Exchange phase which was obvious from the ongoing discussion
You asked for entire configurations - Wassim indicated earlier in the discussion that the customer is not willing to display the entire configuration so we have to use only the information posted so far
You asked for the show ip ospf int bvi1 - the output of this interface was given by Wassim for one router (yes, not for both), and the configuration appeared to be OK so far.

Your descripton of the "encapsulation failed" is correct but the reference to ARP is not appropriate at this point: Wassim is using IP directly over ATM AAL5 in this DSL configuration and there are no Ethernet frames involved - there is no ARP on plain ATM. Also, Wassim indicated that it is possible to ping the headend router, and because of NBMA OSPF configuration, the OSPF should be also using unicast packets only, so there seems to be something fishy in the OSPF communication itself.

Once again, I don't want to prevent you in any way from helping and I am glad you are participating - this is a collaboration forum so this is exactly what the NetPro is about - but if you decide to step in a discussion please first make sure that you are acquainted with the issue.

Looking forward to cooperating with you on this topic

Best regards,

Peter