IP Address Question

triplebenc

Whats up, on the cisco website they have ccna practice exams, and for some reason i cant understand how they came up w/ this answer on question #11. and if somebody could tell me how they got "193" i'd really appreciate it, thanks!


The website is:

http://www.cisco.com/warp/public/10/wwtraining/certcommunity/images/CCNA3.swf

Question 11

jsond

I understand why 192.168.16.193/30 would be the answer but I agree with you I don't understand why .193 would be used.

As this is a point to point serial link it has to be one of the 3 answers with the /30 mask (/30 gives you 4 host addresses, 2 usable..perfect for point to point links i.e "efficient"). You cannot use either 192.168.16.113 or 192.168.16.145 because those 2 addresses fall into the range of addresses already utilized in this network. (192.168.16.113 is being utilized in network 192.168.16.96/27 and 192.168.16.145 is being utilized in network 192.168.16.128/27).

So the only answer left would be 192.168.16.193. I agree it doesn't seem to make sense using .193. I would think the best answer would have been 192.168.16.160/30. Hope this helps but I would wait for a better reply as there are many more here than know way more than I and can probably explain it much better.

QUIX0TIC

Jsond... you pretty much answered it very thoroughly. You cannot use two of them because they are in the other used networks and you want to use a /30 network. I wouldnt look too deep into why they picked .193. I think the point is that you saw the other IPs were being used somewhere else. This isnt a design test... it is an administration test.