Help with manual summarization question required.

Can anyone explain the answer to this Boson ICND2 question, the question states:

An engineer has implemented manual route summarisation with EIGRP in which the one summary route is 172.16.128.0/19. Another engineer needs to install a new VLAN & subnet. The following are some of the subnet numbers being considered by the second engineer for the new subnet. Which one lists a subnet that would not be represented as part of the existing summary route?

A. 172.16.144.0/28

B. 172.16.164.160/28

C. 172.16.180.0/28

D. 172.16.124.0/28

E. 172.16.152.128/28

The answers are B & C but D also does not overlap? The explanation states that the summary route represents the following range of numbers:

172.16.128.0 - 172.16.159.255

The answers represent:

172.16.144.0/28: 172.16.144.0 - 172.16.144.15

172.16.152.128/28: 172.16.152.128 - 172.16.152.143

172.16.164.160/28: 172.16.164.160 - 172.16.164.175

172.16.180.0/28: 172.16.180.0 - 172.16.180.15

172.16.124.0/28: 172.16.124.0 - 172.16.124.15

What am I missing?

Reply to
Jason
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you are correct jason .. /19 --> 32 blocksize ... 172.16.128.0 -- 172.16.159.255

since D is only / 28 --> 16 block size .. 172.16.124.0 -- 172.16.124.15 which does not over lap.

if your book has a website, i'd check there for corrections... it happens from time to time.. its all good.. you are not crazy ..

Reply to
PSK

"PSK" wrote in news:nf%Pj.1913$XI1.335@edtnps91:

Thanks for putting my mind at ease, it made no sense to me.

Reply to
Jason

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