New OSPF Practice Questions

Webmaster

I just added a 10 questions OSPF practice exam:

www.techexams.net/ciexam/start.php?exam=ccna_ospf

I will add about 5 more questions for this CCNA version of the practice exam and than add 10 or 15 more for a BSCI version...

viper75

Thanks!!!

Just took the test and got 1 wrong.

tunerX

I got number 9 wrong, the one about who will be DR. I wasn't expecting it to be a trick question:) Cisco would at least label the interfaces.

viper75

tunerX wrote:

I got number 9 wrong, the one about who will be DR. I wasn't expecting it to be a trick question:) Cisco would at least label the interfaces.

hehe...that's the one I got wrong.

tunerX

Don't you think he should label the router interfaces.

Webmaster

It's actually a question I wrote for the BSCI exam (before OSPF was such an essential topic in CCNA).

There is something to say for labeling the interfaces, Cisco would do that indeed, but IMO it is obvious already. The diagram isn't even needed to answer the question, as all the info you need is in the text already. And it is supposed to be a tricky one, so don't blame the question or the lack of labels for getting it wrong.

tunerX

If the interfaces were frame-relay I could have a DR/BDR election. The diagram would look the same.

Webmaster

Yeah, and if it were a broadcast network it would too elect a DR. It doesn't explicitely mention frame relay, and there's no reason to assume it is a frame-relay network. Frame-relay in NBMA would actually require a manual configuration of DR/BDR selection, and there would be a cloud in the diagram.

Serial interfaces with frame relay encapsulation with subinterfaces (again it would of course be mentioned in the question) in a point-to-point or point-to-multipoint network default to OSPF network type point-to-point and non-broadcast respectively and in neither case a DR would be elected. Serial interfaces with frame relay encapsulation and no subinterfaces would still default to the OSPF network type non-broadcast in which there is no DR/BDR election.

Anyway, the question explicitely mentions 'point-to-point network' which is one of the 5 types of networks for OSPF:
- Point-to-point nonbroadcast (Cisco style) - no DR/BDR
- Point-to-point (Cisco style) - no DR/BDR
- Point-to-multipoint (RFC232 - no DR/BDR
- Broadcast (Cisco style) - DR/BDR election based on router ID (highest loopback or IP, or priority based)
- NBMA (RFC232 - DR manually configured

So combining the text 'point-to-point network' and diagram can lead to only one answer, labeling the interfaces wouldn't change a thing.

tunerX

Lucky thing your question wasn't on the CCIE written:)

keenon

i did ok.. 7 out of 10

Webmaster

Lucky thing your question wasn't on the CCIE written:)

Don't worry, I think most CCIEs and those who've taken the CCIE written exam would be pleased with 90% on any cisco test or practice exam. Like I said, it is supposed to be tricky. If noone would make a mistake in my practice exams I would be doing something wrong.

Drakonblayde

I scored a 90 as well, but I'm not copping to which one I missed (it wasn't #9 )

And he's right, the diagram isn't even necessary. The words 'point-to-point' in the text of the question is a dead giveaway hehe

Elwood151

The question about which network statements would work is technically correct; however, it teaches a really bad practice. The supernet formed for the 192.168.1.0 and 192.168.2.0 networks is an incredibly bad idea. While it would work it would create problems if you wanted to place 192.168.*.0 networks anywhere else in your OSPF AS.

Drakonblayde

That would be true, if the network statements in OSPF actually had a direct effect on what the routing table displays. But the only thing the network statement does for OSPF is tell the router which interfaces are going to participate in the OSPF process. So anything matching the mask you specify will be put in. The only time that would be a bad idea is if within the range you specify, an interface *isn't* supposed to participate, but that question is specifically saying you want all those interfaces in the process

Webmaster

Thanks for the explanation Drakonblayde

I agree it isn't something one shouldn't do in a real-world scenario though. But the main purpose of that particular practice question is to make people learn/remember you have to use a wildcard mask and add interfaces ('link'-state protocol) instead of networks to the OSPF process.

Paddington

Bummer only got 6 right.
but not a big problem will read about OSPF before i take the CCNA test on monday anyway