Broadcast address determination: An interface has IP 192.168.192.10/29. What broadcast address will hosts on this LAN use?

Difficulty: Easy

Correct Answer: 192.168.192.15

Explanation:


Introduction / Context:
For any subnet, the broadcast address is the highest address in that block. With /29, determining the 8-address block is straightforward and frequently tested.



Given Data / Assumptions:

  • Host: 192.168.192.10/29
  • /29 mask = 255.255.255.248 (block size 8)


Concept / Approach:
Identify the /29 block containing .10 by finding the nearest lower multiple of 8 and then adding 7 for the broadcast address.



Step-by-Step Solution:

Block boundaries (4th octet) every 8: 0, 8, 16, 24, ....10 lies in the 8–15 block.Network = .8, Broadcast = .15, Hosts = .9–.14.


Verification / Alternative check:
Compute: 10 - (10 mod 8) = 8; broadcast = 8 + 7 = 15.



Why Other Options Are Wrong:

  • .31/.63/.127: Broadcasts for larger subnets (/27, /26, /25), not /29.
  • .11: A valid host, not the broadcast.


Common Pitfalls:
Forgetting that /29 uses 8-address blocks; misidentifying the correct block around the host.



Final Answer:
192.168.192.15

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