OSPF - bug or features?

RouterOS Forwarding Protocols
1

Sorry for bad English

With the loss of adjacency with the neighbor (no longer receives hello packets due to disconnection) Mikrotik removes the active routes from the kernel, but does not delete the LSA from the base OSPF. In some cases this leads to a routing loop.

Example:

network — neighbor1(area1) - / - Mikrotik(ABR) — neighbor0(area0, ASBR)

Mikrotik is ABR, LSA receives from neighbor1 and distributes area0. Adjacency with neighbor1 lost, but continues to distribute Mikrotik LSA in area0, while deleting a route to the network from the kernel. A packet with destination network will be forwarded to the Mikrotik, Mikrotik but no route to that network, it will forward the package to neighbor0, neighbor0 send the package back as he continues to receive an invalid LSA from Mikrotik - there is a loop route.

2

Hmm, here the same problem:
http://forum.mikrotik.com/viewtopic.php?f=14&t=42606&start=0

3

What a coincidence, I am the author of the other stagnant LSA post. Out of curiosity, what firmware are you running?

This is definitely not a feature, and can cause issues in a network, especially in other use cases (router moves locations).

This can be confirmed as a Mikrotik specific issue, and not an OSPF one, by creating the same lab with other network gear (specifically Cisco).

4

I have seen this problem in versions 4.9, 4.10, 5beta.

5

yes, we experienced the same.. its also in all 3.x ros versions i’ve tested. mtik support doesn’t care, or doesn’t understand, maybe both.

they should have stayed with quagga :-/