ICND1 Subnetting 5

Question 1

Which address is the network address of the subnet containing host 192.168.100.77/28?

Accepted Answer

192.168.100.64

Answer

A /28 has a block size of 16; 77 ÷ 16 = 4 remainder 13, so the subnet starts at 4 × 16 = 64.

Question 2

What CIDR notation represents the subnet mask 255.255.255.192?

Accepted Answer

/26

Answer

255.255.255.192 has 26 bits set (24 + 2 from the last octet: 11000000), giving /26.

Question 3

You have 10.0.0.0/8 and need to create subnets for WAN links using the least address space. Which mask is most efficient for a two-router serial link?

Accepted Answer

/30

Answer

A /30 provides exactly 2 usable host addresses, which is precisely what a point-to-point WAN link requires.

Question 4

If a router has the interface IP 172.20.0.1/23, which network does it belong to?

Accepted Answer

172.20.0.0

Answer

A /23 has a block size of 2 in the third octet; 0 ÷ 2 = 0, so the network is 172.20.0.0.

Question 5

How many subnets and hosts per subnet does 10.0.0.0/8 subnetted to /12 provide?

Accepted Answer

16 subnets, 1,048,574 hosts each

Answer

12 - 8 = 4 borrowed bits → 2^4 = 16 subnets; 32 - 12 = 20 host bits → 2^20 - 2 = 1,048,574 hosts each.

(ICND1) Interconnecting Cisco Networking Devices Part 1 Practice Test

(ICND1) Interconnecting Cisco Networking Devices Part 1 Practice Test

ICND1 Subnetting 5