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+2 votes
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You need $500$ subnets, each with about $100$ usable host address per subnet. What network mask will you assign using a class B network address?

  1. $255.255.255.252$
  2. $255.255.255.128$
  3. $255.255.255.0$
  4. $255.255.254.0$
in Computer Networks by Veteran (425k points)
edited by | 322 views

3 Answers

+4 votes
ans is option 2

class B default net mask 255.255.0.0  (11111111  11111111  00000000  00000000)

to have 500 subnets  9 more bits are required to be included in subnet mask  

so subnet mask will be 255.255.255.128  ( 11111111  11111111  11111111  10000000)

each subnet mask has 7 bits for host-part   which are sufficient for 100 hosts
by Boss (48.8k points)
+4 votes

In subnet mask network and subnet bits represent by one and host bits represent by zero. 

by Boss (35.7k points)
0 votes

In class B network the first 16 bits will be the network id and the rest of the bits will be for the host ids.

In subnetting the host id is further borrowed.for 500 subnets to be possible at least 9 bits should be borrowed from the host id part.when 9 bits are borrowed from the host id atmost 510 subnets will be possible.

From the rest of the 7 bits 126 hosts will be possible for each subnet.

Therefore option (b) is correct

by (47 points)

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