For Class A, all addresses beginning with 10 For Class B, addresses from 172.16 to 172.31
For Class C, addresses from 192.168.0 to 192.168.255
NAT translates a private IP address to a public IP address and there is a one to one ratio of
private to public addresses. PAT includes the port number which is unique for each
translation so a single public IP address can be used to translate multiple private IP addresses.
Larger address space-IPv4 addresses are 32 bits, which provide a theoretical four
billion addresses. IPv6 addresses are 128 bits, so the number of possible addresses
can be expressed as 34 followed by 37 0s, or 340 trillion trillion trillion. Hierarchical
address space-Unlike IPv4, in which numbers in the address have little meaning other
than the address class, and the network ID and host ID, IPv6 addresses have a more
defined structure. Autoconfiguration-IPv6 can be self-configuring or autoconfigured
from a router or server running IPv6 or through DHCPv6. Built-in quality of service
(QoS) support-IPv6 includes built-in fields in packet headers to support QoS
strategies. Built-in support for security-From the ground up, IPv6 is built to support
secure protocols, such as Internet Protocol Security (IPsec). Support for mobility-
With built-in support for mobility, routing IPv6 packets generated by mobile devices
over the Internet is more efficient than with IPv4. Extensibility-IPv6 uses extension
headers instead of IPv4’s fixed-size 40-byte header.