Problems to establish a virtual-link

[draftuncle]

Hi guys:

This is my first post. I was playing a bit with gns3 and I found out a problem. I have a virtual link in between 2 routers (R8 and R11) that is not comming up. I checked the debug and seems that the DBD is not being sent but I dont know why. On the same topology I have another virtual-link in between R1 and R8 that is working fine.

I will forward you all the logs below as Im fully lost:

R11#show run | sec rout
router ospf 2
log-adjacency-changes
area 2 virtual-link 8.8.8.8
network 11.11.11.11 0.0.0.0 area 2
network 11.11.12.0 0.0.0.255 area 2
network 11.11.13.0 0.0.0.255 area 2
network 11.11.17.0 0.0.0.255 area 3

R8#show run | sec rout
router ospf 2
log-adjacency-changes
area 1 virtual-link 1.1.1.1
area 2 virtual-link 11.11.11.11
network 8.8.8.8 0.0.0.0 area 1
network 10.10.10.0 0.0.0.255 area 1
network 88.88.88.0 0.0.0.255 area 2
network 88.88.89.0 0.0.0.255 area 2

===========================================================

R8#show ip ospf virtual-link
Virtual Link OSPF_VL1 to router 11.11.11.11 is up
Run as demand circuit
DoNotAge LSA allowed.
Transit area 2, via interface Serial0/0, Cost of using 128
Transmit Delay is 1 sec, State POINT_TO_POINT,
Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
Hello due in 00:00:00
Adjacency State EXCHANGE (Hello suppressed)
Index 2/2, retransmission queue length 0, number of retransmission 0
First 0x0(0)/0x0(0) Next 0x0(0)/0x0(0)
Last retransmission scan length is 0, maximum is 0
Last retransmission scan time is 0 msec, maximum is 0 msec

Virtual Link OSPF_VL0 to router 1.1.1.1 is up
Run as demand circuit
DoNotAge LSA allowed.
Transit area 1, via interface Ethernet0/0, Cost of using 10
Transmit Delay is 1 sec, State POINT_TO_POINT,
Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
Hello due in 00:00:05
Adjacency State FULL (Hello suppressed)
Index 1/4, retransmission queue length 0, number of retransmission 203
First 0x0(0)/0x0(0) Next 0x0(0)/0x0(0)
Last retransmission scan length is 2, maximum is 9
Last retransmission scan time is 0 msec, maximum is 0 msec

=================

R11#show ip ospf virtual-links
Virtual Link OSPF_VL0 to router 8.8.8.8 is up
Run as demand circuit
DoNotAge LSA allowed.
Transit area 2, via interface Serial0/2, Cost of using 128
Transmit Delay is 1 sec, State POINT_TO_POINT,
Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
Hello due in 00:00:06
Adjacency State EXSTART (Hello suppressed)
Index 0/0, retransmission queue length 0, number of retransmission 0
First 0x0(0)/0x0(0) Next 0x0(0)/0x0(0)
Last retransmission scan length is 0, maximum is 0
Last retransmission scan time is 0 msec, maximum is 0 msec
Number of retransmissions for last database description packet 5

[Georg Pauwen · Accepted solution]

Hello,

at first glance, I would say 11.11.11.11 needs to be in area 3. If your transit area is area 2, and you want the virtual link between area 1 and area 3, the config needs to be:

R11#show run | sec rout
router ospf 2
log-adjacency-changes
area 2 virtual-link 8.8.8.8
network 11.11.11.11 0.0.0.0 area 3
network 11.11.12.0 0.0.0.255 area 2
network 11.11.13.0 0.0.0.255 area 2
network 11.11.17.0 0.0.0.255 area 3

R8#show run | sec rout
router ospf 2
log-adjacency-changes
area 1 virtual-link 1.1.1.1
area 2 virtual-link 11.11.11.11
network 8.8.8.8 0.0.0.0 area 1
network 10.10.10.0 0.0.0.255 area 1
network 88.88.88.0 0.0.0.255 area 2
network 88.88.89.0 0.0.0.255 area 2

[paul driver]

Hello

You will need two VL to complete the connection

R11 <abr)
area 2  virtual-link (r8 rid)

R8 <abr)
area 2  virtual-link (r11 rid)
area 1 virtual-link (r1 rid)

R1 <abr)
area 1  virtual-link (r8 rid)

res

Paul

[draftuncle]

Hi Paul:

Thanks for the answer but the virtual-link in between R1 and R8 is working and working fine. You can see it on the logs that I posted before:

R8#show ip ospf virtual-link
Virtual Link OSPF_VL1 to router 11.11.11.11 is up
Run as demand circuit
DoNotAge LSA allowed.
Transit area 2, via interface Serial0/0, Cost of using 128
Transmit Delay is 1 sec, State POINT_TO_POINT,
Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
Hello due in 00:00:00
Adjacency State EXCHANGE (Hello suppressed)
Index 2/2, retransmission queue length 0, number of retransmission 0
First 0x0(0)/0x0(0) Next 0x0(0)/0x0(0)
Last retransmission scan length is 0, maximum is 0
Last retransmission scan time is 0 msec, maximum is 0 msec

Virtual Link OSPF_VL0 to router 1.1.1.1 is up
Run as demand circuit
DoNotAge LSA allowed.
Transit area 1, via interface Ethernet0/0, Cost of using 10
Transmit Delay is 1 sec, State POINT_TO_POINT,
Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
Hello due in 00:00:05
Adjacency State FULL (Hello suppressed)
Index 1/4, retransmission queue length 0, number of retransmission 203
First 0x0(0)/0x0(0) Next 0x0(0)/0x0(0)
Last retransmission scan length is 2, maximum is 9
Last retransmission scan time is 0 msec, maximum is 0 msec

[Georg Pauwen]

Did you put 11.11.11.11 in area 3 ? Right now you have it configured as belonging to your transit area, that cannot work...

[draftuncle]

Hi Georg:

Thanks for the answer. I made the change as you said and it came up for a few seconds but it dropped again as the connection in between R10 and R11 seems to be flapping. I checked the configuration on both routers and seem to be ok. 

I made a reload on the 4 routers that are on area 2 but didnt help basically they are doing the same. What I can see that might give a clue is that there are constant flaps on the serial interfaces that connect the central routers (R9 and R10) with R11 and R8

(from R10)

*Mar 1 00:45:32.014: %OSPF-5-ADJCHG: Process 2, Nbr 8.8.8.8 on Serial0/0 from FULL to DOWN, Neighbor Down: Dead timer expired

I can see that the serial interface that connects R11 and R8 is flapping due to timer expiration and this is not letting the virtual-link to come up.  So the question here is. Why I have flaps in the route in between R10 and R8?

Example of flaps in R10:

*Mar 1 00:12:01.663: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/0, changed state to down
*Mar 1 00:12:01.667: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/2, changed state to down
*Mar 1 00:12:01.675: %OSPF-5-ADJCHG: Process 2, Nbr 8.8.8.8 on Serial0/0 from FULL to DOWN, Neighbor Down: Interface down or detached
*Mar 1 00:12:11.655: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/0, changed state to up
*Mar 1 00:12:11.675: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/2, changed state to up
*Mar 1 00:12:11.695: %OSPF-5-ADJCHG: Process 2, Nbr 8.8.8.8 on Serial0/0 from LOADING to FULL, Loading Done
*Mar 1 00:12:12.040: %OSPF-5-ADJCHG: Process 2, Nbr 11.11.11.11 on Serial0/2 from LOADING to FULL, Loading Done

==============

Configuration of the devices:

R11#show run | sec rout
router ospf 2
log-adjacency-changes
area 2 virtual-link 8.8.8.8
network 11.11.11.11 0.0.0.0 area 3
network 11.11.12.0 0.0.0.255 area 2
network 11.11.13.0 0.0.0.255 area 2
network 11.11.17.0 0.0.0.255 area 3

R9#show run | sec rout
router ospf 2
log-adjacency-changes
network 9.9.9.9 0.0.0.0 area 2
network 11.11.13.0 0.0.0.255 area 2
network 88.88.89.0 0.0.0.255 area 2

R10#show run | sec rout
router ospf 2
log-adjacency-changes
network 10.1.1.0 0.0.0.255 area 2
network 11.11.12.0 0.0.0.255 area 2
network 12.12.11.0 0.0.0.255 area 2
network 88.88.88.0 0.0.0.255 area 2

R8#show run | sec rout
router ospf 2
log-adjacency-changes
area 1 virtual-link 1.1.1.1
area 2 virtual-link 11.11.11.11
network 8.8.8.8 0.0.0.0 area 1
network 10.10.10.0 0.0.0.255 area 1
network 88.88.88.0 0.0.0.255 area 2
network 88.88.89.0 0.0.0.255 area 2

Even sometimes now is establishing the virtual-link:

Neighbor ID Pri State Dead Time Address Interface
8.8.8.8 0 FULL/ - - 88.88.89.89 OSPF_VL0
9.9.9.9 0 FULL/ - 00:00:35 11.11.13.1 Serial0/0
10.1.1.10 0 FULL/ - 00:00:37 11.11.12.1 Serial0/2
17.17.17.17 1 FULL/DR 00:00:34 11.11.17.2 FastEthernet1/0

[draftuncle]

Logs from R10 and R9:

R10#
*Mar 1 00:23:21.689: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/0, changed state to down
*Mar 1 00:23:21.697: %OSPF-5-ADJCHG: Process 2, Nbr 8.8.8.8 on Serial0/0 from FULL to DOWN, Neighbor Down: Interface down or detached
R10#
*Mar 1 00:23:31.682: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/0, changed state to up
*Mar 1 00:23:32.162: %OSPF-5-ADJCHG: Process 2, Nbr 8.8.8.8 on Serial0/0 from LOADING to FULL, Loading Done

R9#
*Mar 1 00:23:12.510: %OSPF-5-ADJCHG: Process 2, Nbr 11.11.11.11 on Serial0/0 from FULL to DOWN, Neighbor Down : Interface down or detached
*Mar 1 00:23:12.514: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/0, changed state to down
R9#
*Mar 1 00:23:22.503: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/0, changed state to up
*Mar 1 00:23:22.567: %OSPF-5-ADJCHG: Process 2, Nbr 11.11.11.11 on Serial0/0 from LOADING to FULL, Loading Do

[Georg Pauwen]

The links from R9 and R10 to R11 need to be in area 3.

[draftuncle]

No no because they are in a central area that is area 2. Anyway I left it flapping for like 5 min and suddenly it started working without problems. Probably the dead timers need to synchronize or something I dont know but now is working fine aparently so basically it was the problem that you said. WHat I dont understand is why those flaps appeared. 

Anyway thanks a lot for the help :)