MikroTik OSPF and Foundry

RouterOS General
1

Hello true guru’s of the world, I humbly beseech your guidance. :stuck_out_tongue:


I have a RB500 with version 2.9.51 running OSPF with neighboring Layer 3 Foundry switches. Everything works perfectly, until I upgrade the MikroTik software. Once I upgrade to anything current, the OSPF neighbor state flaps between EXSTART and 2-WAY, and the MikroTik log fills with the following message which re-occurs every second:

route ospf info - Discarding Database Description packet: different MTU
mine=1500
remote=0

If I downgrade back to 2.9.51 the problem goes away and everything works perfectly once again. I have confirmed that all interface MTU’s are set correctly, and that the Ethernet settings are good. At this point it appears that a change was made in version 3.0+ that altered the expected format of the OSPF LSA’s.

So how about it, has anyone seen this issue before? Is there a resolution?

2

Thank you for the report.
New version will contains fix for OSPF issues, when remote end reports about MTU 0.

3

I look forward to the new release revision then.

Thanks!

4

I see that a new version of the RouterOS has been released, but do not see anything in the changelog that relates to this issue. Has it been fixed? Or were you referring to the next major revision (i.e. 4.0) as the fix implementation date?

Thanks,

5

This improvement is not included into changelog. The fix for MTU is included into 3.10 version, you need to upgrade router and check the results.