A network technician needs to allocate an IPv4 subnet for a new branch department that req… — CompTIA Network+

A network technician needs to allocate an IPv4 subnet for a new branch department that requires $50$ workstation IP addresses, $2$ printer IP addresses, and $1$ default gateway IP address. What is the maximum number of additional usable host addresses remaining in the smallest CIDR subnet that satisfies these requirements?

$9$ Answer
B
$11$
C
$73$
D
$21$

Answer

The maximum number of additional usable host addresses remaining in the smallest CIDR subnet is

9

The required usable host count is

50 + 2 + 1 = 53

addresses. The smallest CIDR prefix capable of supporting at least

53

host addresses is

/26

(

6

host bits), offering

2^6 - 2 = 62

usable host IPs (

/27

only provides

30

). Subtracting the

53

required addresses from

62

total usable addresses leaves

9

additional usable host addresses for growth.

Step-by-Step Solution

Calculate total required usable IP addresses

50 \text{ workstations} + 2 \text{ printers} + 1 \text{ gateway} = 53 \text{ usable host IPs}

All active devices and router interfaces in the subnet require a unique usable IPv4 address.

Determine the smallest CIDR subnet mask for 53 hosts

/26

subnet (

6

host bits) yields

2^6 - 2 = 62

usable host addresses.

/27

subnet (

5

host bits) only provides

2^5 - 2 = 30

usable addresses, which is insufficient. The

/26

mask is the smallest block that fits

53

hosts.

Calculate remaining usable host address capacity

62 \text{ total usable addresses} - 53 \text{ assigned addresses} = 9 \text{ remaining usable addresses}

Subtracting assigned IPs from total usable subnet IPs gives the spare host address capacity.

Key Concept

Subnet Usable Host Capacity Calculation (

2^h - 2

)

Question

Answer

Step-by-Step Solution

Key Concept

Common Mistakes

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