Compare the address space between IPv4 and IPv6. How many bits are used in each?
The correct answer and explanation is :
The address space between IPv4 and IPv6 differs significantly in terms of the number of bits used for addressing and the total number of possible addresses each protocol can support.
IPv4 Address Space:
- Bits Used: IPv4 uses 32 bits for addressing.
- Address Space: Since each address is represented by 32 bits, the total number of possible unique addresses is calculated as: 232=4,294,967,296 addresses.2^{32} = 4,294,967,296 \text{ addresses}. IPv4 addresses are written in decimal format as four octets (e.g., 192.168.1.1), with each octet representing 8 bits (a byte). Despite this large number of addresses, the growth of internet-connected devices over time has led to the exhaustion of available IPv4 addresses, which prompted the development of IPv6.
IPv6 Address Space:
- Bits Used: IPv6 uses 128 bits for addressing.
- Address Space: The use of 128 bits allows for a significantly larger address space. The total number of possible unique addresses in IPv6 is: 2128≈3.4×1038 addresses.2^{128} \approx 3.4 \times 10^{38} \text{ addresses}. This vast number is more than sufficient to provide unique addresses for every device on the planet for the foreseeable future. IPv6 addresses are written in hexadecimal format, divided into eight groups of four hexadecimal digits (e.g., 2001:0db8:85a3:0000:0000:8a2e:0370:7334).
Comparison:
- IPv4: With only 32 bits, IPv4 can support approximately 4.3 billion unique addresses. This limit has caused issues with address exhaustion, leading to techniques like Network Address Translation (NAT) to extend the usage of IPv4 addresses.
- IPv6: With 128 bits, IPv6 can theoretically support around 340 undecillion addresses. This immense address space allows for far greater scalability, addressing every device on the internet and accommodating future growth without the limitations seen in IPv4.
In conclusion, the transition from IPv4 to IPv6 was necessary to ensure that the world can continue to grow its network infrastructure, providing an almost unlimited number of addresses.