OSPF Quiz
Hi All
Sadly the quiz engine isn’t working as it should. However the questions below are still the same and should still help you if you want to dive deep into OSPF.
[mtouchquiz 1]
Hi All
Sadly the quiz engine isn’t working as it should. However the questions below are still the same and should still help you if you want to dive deep into OSPF.
[mtouchquiz 1]
Great quiz!
It was tough. Got 83% on it. Missed on LSInfinity (chose 65535) and the type-4 LSA (chose when type-5 was received on ABR).
Looking forward to new ones 🙂
Thanks for the feedback Daniel. The LSInfinity one is a contentious question to be fair.
Dont confuse max metric with LSinfinity :
RFC2328 > B. Architectural Constants
LSInfinity
The metric value indicating that the destination described by an
LSA is unreachable. Used in summary-LSAs and AS-external-LSAs as
an alternative to premature aging (see Section 14.1). It is
defined to be the 24-bit binary value of all ones: 0xffffff.
Fair point. I think that the word LSInfinity is overloaded in the standards. Can you have a quick look at http://thenetworksherpa.com/ospf-lsinfinity-not-equal-lsinfinity/ and let me know if you disagree with the source. To be honest I’d love to find an RFC or a section of one that properly clears up the confusion. Happy to be wrong here.
Very nice questions and a slick interface to boot…
Cheers Gary.
Great quiz! I got three wrong (same as Daniel and #7 as well. Was confused how I got 85%, but it seems you award partial credit for getting the right answer on your second try.
Well done!
A colleague got 96% this morning, which I thought was odd too for an 8-question exam. I like the partial credit, it seems a little fairer.
Really nice interface, smooth, runs well. You going to do more?
I got tripped up on the 65535 vs 16777342 one too, went with 16777342
Hey Jeff,
I probably will do another one, not sure when though. It’s hard to generate good questions. Actually it’s making sure I have the answers right is the hard part. No promises, but what would be a valuable space to cover, more OSPF or other topics?
Tricky questions. but nice refreshment in corners of ospf. Thanks john. Please do more
Q1 : There are no other routers on that network segment. RouterA has the DR role for that segment.
The question is misleading. How come the RouterA has the DR role without any neighbor ? The DR role is negotiated during the adj process.
Q4 : When does the ABR originate a type-4 summary on a Cisco router?
I think that we can go deeper. Based on what is the ABR generating the LSA4 ?
Dan
Hi Dan,
Thanks for the comment. I’m not sure that I’m misleading people about the DR role in Q1. You are correct that the DR is negotiated during the ADJ process, but what if there are no other speakers on that LAN segment when an OSPF interface starts-up.
A router with an interface type of BCAST will correctly nominate itself as the DR if it hears from no other OSPF speakers before the expiry of the WAIT timer. Another speaker can then start up on the wire, learn of the existing DR (and move on the the subsequent steps of the adj formation process).
I take your point on Q4. I guess I’m interested in the timing of the type-4 generation. I like your angle too.
/John H
got perfect score :)… really nice set of questions to refresh key points you have in blog posts.
How are you doing john .. I miss ospf already 🙁 .. got only 75%
Hey Rohan,
Going great man. Hope Microsoft are looking after you. I wouldn’t be too worried about 75%, that’s quite a respectable score!.
/John
Great!
Thanks John.
It was a good Quiz mostly theory. It would be better if we have scenario based questions also.
Hi Srinivasa,
Thanks for the feedback. It was indeed theory based. My general philosophy is that you can handle most scenarios if you know the theory. To start, I wanted to create a quiz where the answers were provided in my previous theory-based posts.
That said, I’m always happy to get feedback. Do you have any particular scenarios in mind? Which practical aspects of OSPF do you think are particularly tricky or worth covering? I can’t guarantee I’ll have the time to address your concerns, but always love suggestions from readers.
you hit the nail with q: 4,5 and 7 – makes me think that I need to spend some more time on your website! Never knew about this site, I wonder how did I miss 🙂
cheers John, hopefully your new role gives you some time to get back to this website? 🙂
If you are looking for suggestions on future topics, I would love to see a similar series on the nitty-gritty of BGP and also some firewall/network security concepts! combined with use cases of the type of issues you have seen with designs of ospf/bgp and network security.
take care,
-muddassir
Hi Muddassir,
Thanks for taking the time to comment. The OSPF topics came from a period where I was testing the protocol for Amazon.
I’m doing a fair bit of work on VPNs at the moment, so I might have some posts coming on those topics.
Regards,
John Harrington
WOW I GOT 7 OUT OF 8. Hard to digest.