cancel
Showing results for 
Search instead for 
Did you mean: 
cancel
777
Views
0
Helpful
2
Replies

OSPF Over Tunnel interfaces

Andrew.Bleil
Level 1
Level 1

We are currently having some issues with running ospf over two tunnel interfaces.  Both of these tunnels are originating from the same interface, and thus public IP, but both tunnels have different private ips on both endpoints.  It is because of this that we set up the tunnels with the ospf network type point to point, but we are having some issues.  It appears that the router with both tunnels originating from the same interface is not seeing itself in hellos from the other two routers, and the other two routers are continually retransmitting DBD packets to no avail.  I have already checked the basic things, and all of the parameters for ospf neighborship are matching.  I have been doing some debugging and here is something interesting:

*Mar 22 21:04:38.828: OSPF: Rcv DBD from <hub router> on Tunnel3 seq 0x1F57 opt 0x52 flag 0x2 len 1392 mtu 1476 state EXSTART

*Mar 22 20:20:15.309: OSPF: Rcv DBD from <endpoint router> on Tunnel3 seq 0xE4E opt 0x52 flag 0x7 len 32  mtu 1476 state EXSTART

After some reading online, it appears that the Flag's being different signifies that the routers are assuming the network type is different.  According to the article that I read, the router with the two tunnels originating from the same interface wants this network to be set up as point to multi-point, but this doesn't seem to make sense as each tunnel should be its own point to point interface.  I am curious if anyone has any insight, and or experience with this issue.

I can provide additional information if needed, and thanks in advance for any help.

Andrew

2 Replies 2

Joseph W. Doherty
Hall of Fame
Hall of Fame

Disclaimer

The  Author of this posting offers the information contained within this  posting without consideration and with the reader's understanding that  there's no implied or expressed suitability or fitness for any purpose.  Information provided is for informational purposes only and should not  be construed as rendering professional advice of any kind. Usage of this  posting's information is solely at reader's own risk.

Liability Disclaimer

In  no event shall Author be liable for any damages whatsoever (including,  without limitation, damages for loss of use, data or profit) arising out  of the use or inability to use the posting's information even if Author  has been advised of the possibility of such damage.

Posting

I run OSPF across tunnels, using same physical interface, quite often without issues.  Could you post tunnel and physical interface snipets, both sides; also platforms and IOS versions being used?

I am sorry for the delayed responce, I ended up getting pulled into another issue, but it appears that this was an ISP issue and has resolved itself. 

Thanks for the responce.

Andrew

Review Cisco Networking products for a $25 gift card