1. Module 10: Routing Fundamentals and Subnets 10.2.9 Small Router Purchase Subnetting Example 10.3.5a Basic Subnetting 10.3.5b Subnetting a Class A Network 10.3.5c Subnetting a Class B Network 10.3.5d Subnetting a Class C Network

2. Subnetting Exercise A company has a class C network IP address and needs to subnet so that each Ethernet segment has 10 hosts. 70 hosts are currently needed. Use IP address 200.12.15.0 The following topology has been determined.

4. Question 1.How many subnets are needed to create this structure? 2.How many bits do I need to borrow for subnetting? 3.How many bits are left for the host IDs? 4.What is the subnet mask? 5.What IP address can be allocated for the computers in segment 1 assuming, this has the lowest subnet value. 6.What is the broadcast address for this subnet? 7.Repeat for the other segments

5. 1.12 Subnets are needed 1 per router interface (only 1 subnet needed between 2 directly connected router)

6. 2.If borrowing 2 bits 2 2 – 2 subnets available = 2 If borrowing 3 bits 2 3 – 2 subnets available = 6 If borrowing 5 bits 2 3 – 2 subnets available = 14

7. 3.Class C addresses have 8 bits available for use as host Ids. Using 4 for subnetting leaves 4 bits for hosts. The number of hosts per subnet is:- 2 8-2 -2 = 14 hosts per subnet More that is required (10 +1 for router)

8. 4.The subnet mask in binary is 11111111.11111111.11111111.11110000 Network portion Subnet Hosts This is 255.255.255.240 in dotted decimal notation

9. 5.The lowest subnet IP address start at 200.12. 15.00010001 Network ID Subnet Hosts 17

10. 5.The highest subnet IP address is 200.12. 15.00011110 Network ID Subnet Hosts 30

11. 5.The broadcast IP address for this subnet is 200.12. 15.00011111 Network ID Subnet Hosts 31