OSFP/Network wildcard question

HAMP

For some odd reason I’m not very confident with totally understanding OSPF. OSPF network command and wildcard is what I seem to be stuck on. I didn’t think I was confused until I was going back over some notes (from Odom, CCENT, ICND1 100-101, chap17, page 479, Table 17-5)

To me, these are the same:
Network 10.1.0.0 0.0.255.255
Network 10.1.13.0 0.0.255.255

I’m under the impression that the 0.0.255.255 is telling me to compare the first two octets, which is 10.1.x.x. Why is the book saying/using 10.1.13.x 0.0.255.255, as if it was 10.1.13.x 0.0.0.255 on S0/0/0.
Am I mis-understanding the network portion?

Or is that a typo?

networker050184

I'm guessing that is a typo, but it doesn't really matter. The mask just needs to include the interface IP address. You could do anything from a 0.255.255.255 to a 0.0.0.0 and it wouldn't matter as long as the interface IP is encompassed.

atorven

Typo in the book, Network 10.1.0.0 0.0.255.255 and Network 10.1.13.0 0.0.255.255 mean the same thing that you're only interested in the first 2 octets like you said. You should check out the errata web page for that book.

HAMP

networker050184 wrote: »

I'm guessing that is a typo, but it doesn't really matter. The mask just needs to include the interface IP address. You could do anything from a 0.255.255.255 to a 0.0.0.0 and it wouldn't matter as long as the interface IP is encompassed.

Ok, it looks like all three of us agree. I suppose my thoughts on it isn't as bad as I thought.

atorven wrote: »

Typo in the book, Network 10.1.0.0 0.0.255.255 and Network 10.1.13.0 0.0.255.255 mean the same thing that you're only interested in the first 2 octets like you said. You should check out the errata web page for that book.

Ummm, don't laugh at me too hard with this questions, but what is "the errata web page for that book"?

davenull

A lot of technical books have an errata page online which is basically a collection of typos and errors with corrections. Just googling the name of the book and 'errata' will usually net something.

Here's the errata for the ICND1 Odom's:

CCENT/CCNA ICND1 100-101 Official Cert Guide

Look at the bottom under 'update' tab.

Fun fact: if you read a technical book and haven't found any mistakes read it again, you are not ready yet.

HAMP

davenull wrote: »

A lot of technical books have an errata page online which is basically a collection of typos and errors with corrections. Just googling the name of the book and 'errata' will usually net something.

Here's the errata for the ICND1 Odom's:

CCENT/CCNA ICND1 100-101 Official Cert Guide

Look at the bottom under 'update' tab.

Fun fact: if you read a technical book and haven't found any mistakes read it again, you are not ready yet.

Well, I be darned, I did learn something today. In the past when I came across a typo, I usually catch it, and understand why it is a typo, but this time I just not as confident in knowing OSPF. That is the reason I posted the question.

I just downloaded that sheet, and I noticed what was confusing me, has been updated from a typo.

Now, I need to go back thru the book and see what I have missed, or thought was correct.. Geeez!!


And I really like to Thank atorven for mentioning it. I never knew of such a thing.