CIDR ISSUE
durairaj29
Member Posts: 5 ■□□□□□□□□□
in CCNA & CCENT
Hi
I had gone through one of the websites, from that i got this question, could someone give me the description how could we get this answer
Which two subnetworks would be included in the summarized address of 172.31.80.0 /20? (Choose two.)
A. 172.31.17.4 /30
B. 172.31.51.16 /30
C. 172.31.64.0 /18
D. 172.31.80.0 /22
E. 172.31.92.0 /22
F. 172.31.192.0 /18
Answer: DE
I had gone through one of the websites, from that i got this question, could someone give me the description how could we get this answer
Which two subnetworks would be included in the summarized address of 172.31.80.0 /20? (Choose two.)
A. 172.31.17.4 /30
B. 172.31.51.16 /30
C. 172.31.64.0 /18
D. 172.31.80.0 /22
E. 172.31.92.0 /22
F. 172.31.192.0 /18
Answer: DE
Comments
-
mikearama
Member Posts: 749
durairaj29 wrote:Which two subnetworks would be included in the summarized address of 172.31.80.0 /20? (Choose two.)
A. 172.31.17.4 /30
B. 172.31.51.16 /30
C. 172.31.64.0 /18
D. 172.31.80.0 /22
E. 172.31.92.0 /22
F. 172.31.192.0 /18
Answer: DE
The /20 provides a mask of 255.255.240.0, with the "interesting" last bit falling on the binary point equalling 16. Therefore, this summary address would include every subnet from 172.31.80, plus 16 more... ending at 172.31.96.0
Based on that range, only D and E apply.
HTH's,
MikeThere are only 10 kinds of people... those who understand binary, and those that don't.
CCIE Studies: Written passed: Jan 21/12 Lab Prep: Hours reading: 385. Hours labbing: 110
Taking a time-out to add the CCVP. Capitalizing on a current IPT pilot project.