OSPF Deep Dive Lab

Is the solution to the OSPF Deep Dive Lab ‘Troubleshooting OSPF’ available anywhere because the lab itself doesn’t show it.

Hi Samir,

There are no direct solutions to the lab, as the goal is to simply make OSPF work everywhere, which there may be multiple config options to achieve this. The problems introduced the topology however are the same ones covered in the videos in the playlist. Going back through my notes from the course, some of these problems include:

  • ACL blocking OSPF communication between routers
  • Interfaces in wrong OSPF areas
  • Mismatched MTU
  • Mismatched OSPF area types (e.g. stub vs. nssa)
  • Overlapping OSPF router-IDs
  • Misconfigured OSPF authentication
  • Mismatched OSPF network types
  • OSPF forwarding address learned through non-OSPF protocol (e.g. BGP)
  • OSPF discontiguous areas and virtual-link issues

There are some other issues covered in the videos, but all the issues in the troubleshooting lab are included in the videos. Essentially once you have OSPF 100% working, you know you have solved the lab.

Hope that helps!

Brian McGahan, 4 x CCIE #8593 (R&S/SP/SC/DC), CCDE #2013::13

Hi Brian,

Thanks for responding. I have watched all of your OSPF Deep Dive videos (twice), which are great, btw. And found the 8 different issues in the lab.

However, I just wanted to confirm that the last point in the lab task list (below) is one of the eight issues listed in an earlier point. Or whether it is a separate issue?

Also, when there was a recent circuit outage between R3 and R7, Host7 and Host9 were not able to reach Host5, Host8, or Host10. Resolve the issue so that if you shut down R3’s link to R7, you still have reachability between all five hosts.

And given your knowledge and experience, I’d appreciate some advice… From a CCIE lab troubleshooting perspective, if I were to stumble across something that looks like an issue (such as an ACL blocking OSPF or RID that appears to be duplicated) whilst investigating a specific task, should I address it immediately or simply move on and review when I am instructed to do so? And, in the case of verifying connectivity, should I only check the host-host communication is working (like the lab asks) or literally go from router to router checking LSDBs, pinging all networks, etc?

I know time is limited in the lab exam so I want to find a balance between being thorough to make sure I don’t miss anything and being quick.

Thanks for the advice.


Hi Sam,

The CCIE lab network will be too big for you to have time to check everything in detail. Instead, you’ll have to be more results-oriented and see what kind of test cases you need to check.

In this case, the qualifier for the lab question is: “if you shut down R3’s link to R7, you [should] still have reachability between all five hosts.”

This means that all five hosts should have reachability in the first place. So, I would start testing there, noting and fixing any reachability problems. Once the hosts can reach each other, I would “shut down R3’s link to R7”, give OSPF some time to converge, then start testing and troubleshooting again.

The fact that the qualifier is given to you in the question means that’s what they would be checking for in grading, not necessarily every other little problem that could still possibly be wrong.

Hope that helps!


Hi Brian,

I was aware that I had to read the question carefully so as to correctly interpret what I was actually being asked to do, and to be aware of restrictions, but the verification side was always a little hazy - thanks for clarifying, it’s of great help.

One last question. Would you say that the INE lab tasks are of comparable difficulty, and the task structured similarly, to the actual CCIE lab exam?

Thanks very much again for your help.


If you can comfortably do all the labs in the Final Lab Practice for CCIE Enterprise Infrastructure course, then you’re definitely on target.

Understood and thanks very much again for the tips.