Figure 5-5 Default mask and subnet mask Default mask 255.255.0.0 141.14.72.24 141.14.0.0 AND IP address Network address Without subnetting Subnet mask 255.255.192.0 141.14.72.24 141.14.64.0 AND IP address Network address b With subnetting CSIE NTUT TANAN
CSIE, NTUT, TAIWAN 11 Figure 5-5 Default mask and subnet mask
Straight Method In the straight method we use binary notation for both the address and the mask and then apply the and operation to find the subnet address CSIE NTUT TANAN
CSIE, NTUT, TAIWAN 12 Straight Method In the straight method, we use binary notation for both the address and the mask and then apply the AND operation to find the subnet address
Example 1 What is the subnetwork address if the destination address is 200. 45.3456 and the subnet mask is 255.255.240.0? CSIE NTUT TANAN
CSIE, NTUT, TAIWAN 13 Example 1 What is the subnetwork address if the destination address is 200.45.34.56 and the subnet mask is 255.255.240.0?
Solution 11001000001011010010001000111000 l111111l111111111111000000000000 11001000001011010010000000000000 The subnetwork address is 200. 45.32.0 CSIE NTUT TANAN
CSIE, NTUT, TAIWAN 14 Solution 11001000 00101101 00100010 00111000 11111111 11111111 11110000 00000000 11001000 00101101 00100000 00000000 The subnetwork address is 200.45.32.0
Short- Cut method w x If the byte in the mask is 255, copy the byte in the address ** If the byte in the mask is 0, replace the byte in the address with 0 i* If the byte in the mask is neither 255 nor o we write the mask and the address in binary and apply the and operation CSIE NTUT TANAN
CSIE, NTUT, TAIWAN 15 Short-Cut Method ** If the byte in the mask is 255, copy the byte in the address. ** If the byte in the mask is 0, replace the byte in the address with 0. ** If the byte in the mask is neither 255 nor 0, we write the mask and the address in binary and apply the AND operation