The document discusses IP addressing and network layer concepts. It provides examples of converting IP addresses between binary and dotted-decimal notation. It also describes classful addressing which divides the address space into classes A, B, C, D and E. The document then gives an example of address allocation and distribution to different customer groups. It introduces Network Address Translation (NAT) which allows internal networks to use a large set of private addresses while presenting a single external address.

1. Chapter 19.
Network Layer: Logical Addressing
IPv4 Addresses

2. IPv4 Addresses

6. Example
• Change the following IP addresses from binary notation to dotted-decimal
notation.
a. 10000001 00001011 00001011 11101111
b. 11111001 10011011 11111011 00001111
• We replace each group of 8 bits with its equivalent decimal number and
add dots for separation:
a. 129.11.11.239
b. 249.155.251.15

11. Classful addressing
In classful addressing, the address space is divided into five
classes: A, B, C, D, E

31. Network Address

39. Address Allocation and Distribution: Example
• The first group has 64 customers; each needs 256 addresses.
• The second group has 128 customers; each needs 128 addresses.
• The third group has 128 customers; each needs 64 addresses.

40. 0, 128
64-127= 64, 64*2=128 addresses

41. 0, 64, 128, 192
128-159= 32 , 32*4 = 128 addresses

42. Network Address Translation: NAT
• NAT enables a user to have a large set of addresses internally
and one address, or a small set of addresses, externally.
Addresses for private networks
Range Total
10.0.0.0 to 10.255.255.255 224
172.16.0.0 to 172.31.255.255 220
192.168.0.0 to 192.168.255.255 216

45. Addresses Translation

46. Translation Table

48. Five-Column Translation
Table