OSPF Neighbor intermitantly bounce from Exchange to 2-Way

RouterOS Forwarding Protocols
1

We are have a link between 2 locations on our network that seem to have their OSPF Neighbor Status intermittently bounce from Exchange to 2-Way. Here is a basic layout.

Switch------MikrotikEndRouter----MicrowaveBridge1----------------------------------------MicrowaveBridge2----MikrotikCoreRouter-----CORE-NETWORK

Most of the time everything works fine, however intermittently my OSPF neighbor relationship between the MikrotikEndRouter and MikrotikCoreRouter will start bouncing between Exchange and 2-Way States and the MikrotikEndRouter will be inaccessible except from the local network it belongs to. I.E. I can telnet from MikrotikCoreRouter to MikrotikEndRouter but can’t get to it from anywhere else on my network.

The temporary fix is to reboot the MicrowaveBridge1 and my OSPF Neighbor relationships will start working again from anywhere from a few hours to a few weeks.

I also noticed in my MikrotikCoreRouter logs the error message “Ignoring Link State Acknowledgment packet: wrong peer state=2-Way”

Any thoughts as to what might be causing this issue and what the fix might be? My Microwave Link appears rock solid and I never have problems accessing either of the Microwave radios.

What do you think?

Jim

2

My experience these problems tend to fall in a couple of categories

a)Intermittent Link problems

b)Incorrect/Bad TCP/IP or Firewall Config

c)Non optimal mode chosen for interface ie PtP , PtmP , NBMA , Broadcast . Seriously consider the P2P mode on wireless/sat links.

d)Mikrotik Bug

3

We are currently set to broadcast on these links. Do we need to change all the OSPF links on our network to a different one if we decide to change or can we mix and match, I.E. run broadcast on some and PTP on others?

Also, where do I change the mode from broadcast to point to point and can this be done without affecting the rest of the OSPF network?

Jim

4
  1. The two neighbouring routers mush have same network type set (broadcast, p2p, nbma,…), you don’t need to change to e.g. p2p on all links, but for wireless purposes yes, don’t use broadcast. Use p2p also on vpn links if any. This should not affect whole network (maybe for a little while untill all routes come up again).
  2. you can change network type under /routing ospf interface
5

I noticed that it appears that you can’t change the OSPF interface type (it does not have an option to change in Winbox anyway). Do I need to delete the existing OSPF interface and add a new interface P2P or can I add another OSPF interface type for the existing interface and then delete the current interface that is set to broadcast?

Jim

6

Just add the the new interface statically in winbox in the OSPF interface menu and it will override the dynamically created interface that was created.

Note

Make sure you can get to the remote side via a static/direct route or vpn/ip tunnel otherwise you possibly risk locking yourself out of your own network.