Consider a router that interconnects three subnets: Subnet 1, Subnet 2, and Subnet 3. Suppose all of the interfaces in each of these three subnets are required to have the prefix 223.1.17/24. Also suppose that Subnet 1 is required to support at least 60 interfaces, Subnet 2 is to support at least 90 interfaces, and Subnet 3 is to support at least 12 interfaces. Provide three net- work addresses (of the form a.b.c.d/x) that satisfy these constraints.
Three net- work addresses (of the form a.b.c.d/x) that satisfy given constraints as follows:
223.1.17.0/25
223.1.17.128/26
223.1.17.192/26
A Sample Subnetting Problem
Consider a router that interconnects three subnets: Subnet 1, Subnet 2 and Subnet 3. Suppose all the interfaces in each of these three subnets are required to have the prefix 230.1.17/24.
Also suppose that Subnet 1 is required to support up to 60 interfaces, Subnet 2 is required to support up to 90 interfaces and Subnet 3 is required to support up to 12 interfaces.
Provide three network addresses (of the form a.b.c.d/x) that satisfy these constraints.
Calculations
Recall:
• The network address cannot be used for an interface (Network prefix + all zeros).
• The broadcast address cannot be used for an interface (Network prefix + all ones)
Then:
Subnet 1 requires 60 interfaces + 2 (network + broadcast) =>
so 64 addresses will sufice
Subnet 2 requires 90 interfaces + 2 (network + broadcast) =>
so 128 addresses will sufice
Subnet 3 requires 12 interfaces + 2 (network + broadcast) =>
so 16 addresses will sufice
One Solution that Works:
Sub 2 230.1.17.0/25 à 223.1.17.00000000/25 à 223.1.17.0 to 223.1.17.127 = 128
Sub 1 230.1.17.128/26 à 223.1.17.10000000/26 à 223.1.17.128 to 223.1.17.191 = 64
Sub 3 230.1.17.192/28 à 223.1.17.11000000/28 à 223.1.17.192 to 223.1.17.207 = 16
Post the discussion to improve the above solution.