Written by 4:00 pm Internet

IPv4 vs IPv6 and where did IPv5 go?

IPv4 vs IPv6

Every time you see some network settings, there are IPv4 or IPv6. As you can guess, the previous versions are long in the past (TCP/IP v1, v2, and v3). But why is it IPv4 vs IPv6 instead of the 5th version vs the 6th? How is that the IPv4 from the 80s is still around? Let’s find out!

IP (Internet Protocol)

IP is an abbreviation of internet protocol. The IP is the way devices connect to the internet. It has a set of rules that define how the data travels from host to its destination. To identify all the devices, there are IP addresses that are unique to them.

First, the IP protocol was part of the TCP/IP. The first version that separated from it was the IPv4.


IPv4 looks like this It has 4 numbers that can be from 0 to 254, and are divided by dots. The total number of available IPs is 4 294 967 296. It looks massive, but think about how many connected devices are there. Yes, they are already more, and the internet service providers need to reuse their available IPs. Some are running out of numbers already, and they are starting to provide IPv6 addresses.


Ok, there are almost no IPv4s, why aren’t we moving to the IPv5? Why we skipped it? The reason is that the IPv5 doesn’t exist. It never made it to become one of the IP protocols. It was planned as a streaming protocol, and it got to its second version ST2. Its packets had the IP version 5 ID but eventually died as a draft. To evade confusion, the next protocol was named IPv6.


In contrast to the IPv4 which uses 32-bit addresses, the newer version uses 128bit addressing.  To see the difference we will start with one example of IPv6: “2001:0db8:0000:0042:0000:8a2e:0370:7334”. It has 8 groups, double the number of the previous. Each group has 4 hexadecimal (hex) digits and the groups are separated by colons.

As you can see, there are many more combinations of available IP addresses. To be precise, 1028 time!

Another benefit of the new protocol is the increased security. It has IPsec (Internet security protocol). It authenticates the sender (with Authentication Header) and encrypts the data (Encapsulating Security Payload).

The main problem of the protocol is the slow adoption from the ISPs (internet providers). They mostly prefer to use IPv4 because they don’t want to invest in a new technology. Currently, the adoption rate is 24.65% (date 22.09.2018, Google IPv6 adoption statistic) and the leader is Belgium with 52.94%.

IPv4 vs IPv6

So we are finally getting to the true IPv4 vs IPv6 comparison. Here we are going to put the attention on the fundamental differences that the two protocols have. You will see how much did the new one improve over the IPv4.

Description IPv4 IPv6
Address 32 bit long 128 bit long
Address types Unicast, multicast, and broadcast Unicast, multicast and anycast
Number of IPs 4 294 967 296 2128
Packet size (Maximum transmission unit) 576 bytes required, with fragmentation option 1280 bytes required, no fragmentation
Address configuration Manual or DHCP SLAAC using ICMPv6 or DHCPv6
DNS A records AAAA records
IPsec Optional Mandatory
Transport layers TCP, UDP, RAW TCP, UDP, RAW

Additional benefits of the IPv6

  • Better routing without fragmentation of packets
  • Extended address space (32bit to 128it)
  • IPsec
  • SLAAC – Stateless address auto-configuration
  • An improved structure of the header with less processing overhead

IPv4 vs IPv6, now you know the difference. IPv6 provides enough IPs for a long, long time. We probably won’t see any new version any time soon.

If you liked this comparison, you might also like some of our previous ones:

Router vs firewall, can you guess which is better?

FTP vs HTTP. File Transfer Protocol and Hypertext Transfer Protocol

DNS vs DHCP. Are they connected?

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Tags: , , , , , , , , , Last modified: February 18, 2020