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Subnetting · Cisco / Network Engineer

How do you subnet 10.0.0.0/16 to support 50 subnets each with at least 100 hosts?

Need 50 subnets → 2^6 = 64, so 6 subnet bits. Need 100 hosts/subnet → 2^7 - 2 = 126, so 7 host bits. 16 + 6 + 7 = 29 bits used → /23 prefix would give us 7 host bits and 7 subnet bits (128 subnets). Most accurate answer: /23 mask (255.255.254.0) works — gives 128 subnets of 510 hosts each. Trade-off: address efficiency vs subnet count.
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Q. What's the broadcast address and number of usable hosts for 192.168.1.0/26?

/26 = 255.255.255.192 = 64 addresses per subnet. For 192.168.1.0/26: network address 192.168.1.0, broadcast 192.168.1.63, usable hosts 192.168.1.1–192.168.1.62 (62 usable). Formula: 2^(32-prefix) - 2 = 2^6 - 2 = 62 usabl…
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