Solved: OSPF NBMA question

asldavid · ‎06-09-2013

Hi all,

I try to configure 3 routers trying to talk to each on ospf NBMA.

As you can see, i have put the serial interface on Master on point-to-multipoint and the other 2 router serial interface on point-to-point. After changing the hello-interval on Master, I still can't get the master to form a neighbor relationship with the 2 other router. It keep stuck on exchange state.

Appreciate if anyone can advise on this.

Master

=====

interface Serial0/0.1 multipoint

ip address 10.12.3.1 255.255.255.0

ip ospf network point-to-multipoint

ip ospf hello-interval 10

frame-relay map ip 10.35.6.5 102 broadcast

frame-relay map ip 10.35.6.6 103 broadcast

Master#sh ip ospf int

Serial0/0.1 is up, line protocol is up

Internet Address 10.12.3.1/24, Area 0

Process ID 1, Router ID 1.1.1.1, Network Type POINT_TO_MULTIPOINT, Cost: 64

Transmit Delay is 1 sec, State POINT_TO_MULTIPOINT,

Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5

R2

===

interface Serial0/0.1 point-to-point

ip address 10.12.3.2 255.255.255.0

frame-relay interface-dlci 201

R2#sh ip ospf int

Serial0/0.1 is up, line protocol is up

Internet Address 10.12.3.2/24, Area 0

Process ID 1, Router ID 2.2.2.2, Network Type POINT_TO_POINT, Cost: 64

Transmit Delay is 1 sec, State POINT_TO_POINT,

Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5

R3

===

interface Serial0/0.1 point-to-point

ip address 10.12.3.3 255.255.255.0

frame-relay interface-dlci 301

R3#sh ip ospf int

Serial0/0.1 is up, line protocol is up

Internet Address 10.12.3.3/24, Area 0

Process ID 1, Router ID 3.3.3.3, Network Type POINT_TO_POINT, Cost: 64

Transmit Delay is 1 sec, State POINT_TO_POINT,

Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5

Master#sh ip ospf neighbor

Neighbor ID Pri State Dead Time Address Interface

3.3.3.3 1 EXCHANGE/ - 00:00:37 10.12.3.3 Serial0/0.1

2.2.2.2 1 EXCHANGE/ - 00:00:37 10.12.3.2 Serial0/0.1

Rolf Fischer · ‎06-09-2013

I'm confused about your frame-relay mappings.

Do you have IP-connectivity between Master and Spokes?

frame-relay map ip 10.35.6.5 102 broadcast

frame-relay map ip 10.35.6.6 103 broadcast

Should't you map 10.12.3.2 and .3?

Or are you mixing static and dynamic mapping? This usualy doesn't work after a reboot.

Hope that helps

Rolf

View solution in original post

Richard Burts · ‎06-09-2013

The basic problem is the mismatch of OSPF router types.

State POINT_TO_MULTIPOINT,

State POINT_TO_POINT

In OSPF the behavior on point to point is significantly different from the behavior on multipoint and that prevents forming a successful neighbor relationship. I suggest that you change the OSPF network type on those two routers to match the Master router..

HTH

Rick

HTH

Rick

Rolf Fischer · ‎06-09-2013

Actually a combination of P2P and P2MP should work if you adjust the timers, both do not elect DRs and listen for AllSPFRouters (224.0.0.5).

Stucking in EXCHANGE is often caused by mismatching MTUs, but as far I can see your're using the default values.

Have you tried clearing the OSPF process?

Best Regards

Rolf

asldavid · ‎06-09-2013

Hi Rolf,

I have done clear ip ospf process on all router and also done reboot. But it still stuck on exstart state. I turn on the debug ip ospf events on master and i see the following.. Appreciate your advises..

00:16:35: OSPF: Rcv DBD from 3.3.3.3 on Serial0/0.1 seq 0x1E20 opt 0x42 flag 0x7 len 32 mtu 1500 state EXCHANGE

00:16:35: OSPF: Send DBD to 3.3.3.3 on Serial0/0.1 seq 0x1E20 opt 0x42 flag 0x2 len 52

00:16:35: OSPF: Rcv DBD from 2.2.2.2 on Serial0/0.1 seq 0xA9 opt 0x42 flag 0x7 len 32 mtu 1500 state EXCHANGE

00:16:35: OSPF: Send DBD to 2.2.2.2 on Serial0/0.1 seq 0xA9 opt 0x42 flag 0x2 len 52

00:16:40: OSPF: Rcv DBD from 2.2.2.2 on Serial0/0.1 seq 0xA9 opt 0x42 flag 0x7 len 32 mtu 1500 state EXCHANGE

00:16:40: OSPF: Send DBD to 2.2.2.2 on Serial0/0.1 seq 0xA9 opt 0x42 flag 0x2 len 52

00:16:43: OSPF: Rcv hello from 2.2.2.2 area 0 from Serial0/0.1 10.12.3.2

00:16:43: OSPF: End of hello processing

00:16:43: OSPF: Rcv hello from 3.3.3.3 area 0 from Serial0/0.1 10.12.3.3

00:16:43: OSPF: Cannot see ourself in hello from 3.3.3.3 on Serial0/0.1, state INIT

00:16:43: OSPF: End of hello processing

00:16:45: OSPF: Rcv DBD from 2.2.2.2 on Serial0/0.1 seq 0xA9 opt 0x42 flag 0x7 len 32 mtu 1500 state EXCHANGE

00:16:45: OSPF: Send DBD to 2.2.2.2 on Serial0/0.1 seq 0xA9 opt 0x42 flag 0x2 len 52

00:16:53: OSPF: Rcv hello from 2.2.2.2 area 0 from Serial0/0.1 10.12.3.2

00:16:53: OSPF: Cannot see ourself in hello from 2.2.2.2 on Serial0/0.1, state INIT

00:16:53: OSPF: End of hello processing

asldavid · ‎06-09-2013

Hi Rolf,

You life saver... The issues is with the frame-relay mapping... Great.

Master#sh ip ospf neighbor

Neighbor ID Pri State Dead Time Address Interface

3.3.3.3 1 FULL/ - 00:00:33 10.12.3.3 Serial0/0.1

2.2.2.2 1 FULL/ - 00:00:33 10.12.3.2 Serial0/0.1

Rolf Fischer · ‎06-09-2013

I'm confused about your frame-relay mappings.

Do you have IP-connectivity between Master and Spokes?

frame-relay map ip 10.35.6.5 102 broadcast

frame-relay map ip 10.35.6.6 103 broadcast

Should't you map 10.12.3.2 and .3?

Or are you mixing static and dynamic mapping? This usualy doesn't work after a reboot.

Hope that helps

Rolf

Rolf Fischer · ‎06-09-2013

Oh, you already solved it while I was typing ;-)