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IPv4 and IPv6 are two terms that you will encounter too much in networking world and in Cisco CCNA Certification Exam. In this lesson, we will compare IPv4 and IPv6 and we will learn the differences of these two IP versions. In other words, we will focus on IPv4 vs IPv6. We will start with the question, what is IP or What is Internet Protocol? And then continue with What is IPv4 and What is IPv6? We will also answer the other important questions related with IPv6 vs IPv4.
Then, let’s start with the first question. What is IP?
Table of Contents
IP is the abbreviation of Internet Protocol. Internet Protocol is a network protocol which provides communication of the computers or any other network devices in the network. Internet Protocol (IP) is the most known rule set in computer networking. With these rule sets, it provides network communication.
During data transfer in a network, IP information is used. This information includes a logical address for each device and interface. In networking, we called these logical addresses as ip addresses.
There are two versions of Internet Protocol These are; IPv4 and IPv6. Here we will compare these two versions and we will learn the details of IPv4 vs IPv6. So, we have two different logical ip addresses: IPv4 addresses and Ipv6 addresses.
So, what is IPv4? And what is IPv6? And where is IPv5? or why don’t we use IPv5? Let’s answer these key questions one by one.
Before IPv4 vs IPv6 comparison, let’s learn what is IPv4. IPv4 is the abbreviation of Internet Protocol version 4. It is the first IP version that we use in computer networking. This protocol was introduced at 1982 by DARPA. After one year at 1982, it is developed for SATNET and after that at 1983 for ARPANET.
IPv4 has 32 bits ip address. This ip address is showed with a decimal notation. In an IPv4 address, there are four octets (8 bits) divided by a dot (.). Each octet shows a decimal number from 0 to 255. And totally, four octet and for number divided with dots represents an ip address.
IPv4 address consist of network bits and host bits. The network bits show the network of this ip address and the host parts shows the hosts bits that are used to produce usable host ip addresses in this network.
Below, you can find an example for IPv4 address:
192.168.100.5
This is an example from the private ip address range.
A subnet mask is a 32 bits long value used with an ip address. It is written like ip address with 4 octets (8 bits) divided with dots. It is written in decimal format too. Subnet mask shows the network bits and host bits of an ip address. In a subnet mask there are 1s for the number of network bits and there are 0s for the number of hosts bits. Below you can find an example for this both decimal and binary versions of a subnet mask.
255.255.255.0
11111111.11111111.11111111.00000000
It is also represented as CIDR value after an ip address with a slash and a number from 0 to 32. There is an example for this below:
/24
192.168.100.5/24
Before IPv4 vs IPv6 comparison, let’s also learn what is IPv6?
To learn more on subnetting, you can visit ip subnetting examples lesson.
You can use Subnet Cheat Sheet for subnetting calculations.
IPv6 is the new version of Internet Protocol. It has introduced at 1995 by IETF (Internet Engineering Task Force). Basically, IPv6 has more features and has a larger address space if we compare IPv4 vs IPv6.
As we have talked about above, IPv4 addresses use Decimal notation. In other words, to represent an IPv4 address, we use the numbers between 0-9. Unlike IPv4, IPv6 uses Hexadecimal notation. This means that, to express an IPv6 address, we can use the number from 0 to F.
To provide a larger address space, in this new internet protocol version 128 bits ipv6 addresses are used. In an IPv6 address there are 8 groups. Each group is separated by a colon (:).
Below, you can find an example for an IPv6 address:
2001:AAB1:C231:0000:0000:123:334:1
There are different IPv6 address types.
Technology is evolving day by day and the need for the ip addresses are increasing. Especially, after Internet of Things (IoT) technology, many devices became ip available and has started to use ip addresses to communicate over the networks.
To satisfy this ip address need, existing IPv4 address space was not sufficient. Because there were only 4.3 billion potential ip addresses in IPv4 with 32 bits addresses. The exact number is 2 to the power of 32 which is equal to 4.294.967.296. And all of these address space has exhausted. In other words, the unique IPv4 addresses run out in the world. So, to overcome this need, a new internet protocol version which has more address space was developed. And this is IPv6.
In IPv6 address, there are 128 bits and the available ipv6 address number is equal to 2 to the power of 128. This is 340.282.366.920.938.463.463.374.607.431.768.211.456 addresses.
Beside these, there are also other technical differences between IPv6 and IPv4 like QoS, IPSec, NAT, packet sizes etc. We will discuss all these differences in the below IPv4 vs IPv6 title.
We have IPv4 and after that IPv6. What about IPv5? Where is it? Why don ‘t we use IPv5? IPv5 is the protocol named as Internet Streaming Protocol (ST). But it is not an official standard protocol and used only for experimental works. It was using data transfer on different frequency bands and it was the foundation of Voice over IP (VoIP).
Now, it is time to go through IPv4 vs IPv6 and learn the difference of these two internet protocols.
There are many differences of IPv4 and IPv6. Here, we will compare IPv4 vs IPv6 and we will learn what is the difference between IPv4 and IPv6.
IPv4 vs IPv6 Comparison Table
The first difference between IPv4 and IPv6 is certainly the address space. An IPv4 address is 32 bits. An IPv6 address is 128 bits. This provides to IPv6 a larger ip address space. With 32 bits, the exact address number is 2 to the power of 32 which is equal to 4.294.967.296 in IPv4. With 128 bits, there are more available addresses and this is equal to 2 to the power of 128. This number is 340.282.366.920.938.463.463.374.607.431.768.211.456.
IPv4 addresses uses decimal numbering system. So, from 0 to 255, we can use any number between 0-9 for any octet. And between these octets, IPv4 uses dot (.). IPv6 uses hexadecimal numbering system. We can use both numbers and letter from 0 to F. (0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E, F)
When we compare IPv4 vs IPv6 another difference is about auto ip configuration. In IPv4, we can use DHCP for dynamic ip allocation. We can also use manual ip addressing. In IPv6, there is also an auto ip addressing mechanism.
When we compare IPv4 vs IPv6 on packet sizes, the packet sizes of IPv4 and IPv6 are also different. IPv4 has a variable size header. It can be 20 bytes to 60 bytes. But ipv6 header is fixed 40 bytes long.
In Ipv4 there is no specific security mechanism while IPv6 has IPSec Mechanism form security.
Another difference of IPv6 vs IPv4 is about encryption and authentication. In IPv4, there is not Encryption and Authentication while IPv6 has these features.
IPv4 has some IP Classes, Class A, B, C, D and E. But there are no classes in IPv6 addressing.
IPv4 support VLSM (Variable Length Subnet Mask). There is no VLSM support on IPv6.
In IPv4 there is a Checksum field but IPv6 has no such checksum field.
There is no packet identification in packet flow in IPv4. In other words, there is no efficient Quality of Service (QoS). In IPv6, there is packet identification in packet flow. So, IPv6 QoS is efficient.
In IPv4, both broadcast and multicast transmission are used. But In IPv6, there is no broadcast. Instead of broadcast, multicast is used in IPv6. There is also a new type is used in IPv6, named anycast.
For IPv4, fragmentation is performed by Sender and forwarding routers while fragmentation is performed only by the sender in Ipv6.
In IPv4 end to end, connection integrity is Unachievable while this can be done in IPv6.
You can also check the below table as a summary of IPv4 and IPv6 difference.
| Feature | IPv4 | IPv6 |
| Address Length | 32-bit | 128-bit |
| Address Example | 192.168.1.1 | 2001:db8::1 |
| Address Space | About 4.3 billion | About 3.4 × 1038 |
| Header Size | 20–60 bytes | 40 bytes |
| Broadcast | Supported | Not used |
| Multicast | Supported | Supported |
| Address Configuration | Manual or DHCP | Manual, SLAAC or DHCPv6 |
| NAT | Commonly used | Generally not required for address conservation |
| Fragmentation | Hosts and routers | Source host only |
| Neighbor Resolution | ARP | NDP |
In most modern networks, IPv4 and IPv6 are used together. IPv4 remains widely used for years because of its extensive existing deployment and compatibility. On the other hand, IPv6 is the long-term solution because of its much larger address space and modern addressing capabilities. So, in today’s network world, both IPv4 and IPv6 are used as dual-stack. IPv6 supports new network designs, while IPv4 may still be required for compatibility with existing networks and services.
IPv4 and IPv6 Dual-Stack Network
The below IPv4 vs IPv6 Cheat Sheet will provide you a quick visual reference for the most important differences between IPv4 adn IPv6. Here, we will compare address length, notation, address ranges, ARP vs NDP, broadcast behavior, SLAAC and dual-stack operation, while reviewing key IPv4 and IPv6 concepts.
If you want to download the high-resolution version, you can check our Cheat Sheets page.
IPv4 vs IPv6 Cheat Sheet
In this lesson, we have talked about IPv4 vs IPv6. We have compared these two versions of Internet Protocol. We have detailly answer what is IPv4, what is IPv6 questions. As a network engineer ip addresses will be one of the most used network parameters in your career. So, to learn the details of these protocols will help you a lot in your career. This lesson is also critical for Cisco CCNA Certification Exam. There will be different questions related with ip addresssing in CCNA Exam.
IPv6 does not automatically make your Internet connection faster than IPv4. Internet performance depends on different parameters like routing paths, ISP infrastructure, latency, network configuration etc. IPv6 may perform better in some environments, but simply enabling IPv6 does not guarantee higher Internet speed.
We are using IPv4 for decades in networks, devices, applications and services. This means that, the larger part of the network world are using IPv4. To migrate IPv6, we need comaptible insfrastructure. It can takes decades again to migrate fully IPv6 networks.
IPv6 deployment can introduce additional operational complexity, especially during the transition from IPv4. Network devices, applications, security policies and monitoring systems must properly support IPv6 and administrators need IPv6 knowledge. But in long-term, IPv6 has more advantages.
IPv6 is widely supported, but it has not completely replaced IPv4 today. This is because much of the existing infrastructure and network services still support and depend on IPv4. Migrating to IPv6 need network upgrades, new configurations, IPv6 expertise and additional operational effort. For these reasons, many organizations continue to use IPv4 or operate IPv4 and IPv6 together with dual stack instead of moving completely IPv6.
If you turn off IPv6 on your router, the devices on your network will use IPv4 for communication. Most IPv4-compatible websites and services may continue to work normally, but services or applications that depend on IPv6 may become unavailable.
Disabling IPv6 can also prevent your devices from taking advantage of native IPv6 connectivity provided by your Internet Service Provider. So,you should not disable IPv6 should unless there is a specific network requirement.
Gokhan Kosem is a Network Engineer, Instructor and the Founder of IPCisco.com with 15+ years of experience in Cisco, Nokia, Huawei, Juniper, Linux, Service Provider Networks, Routing and Switching technologies.
He has worked on the backbone networks of major service providers and network vendors including Nortel, Alcatel-Lucent (Nokia) and has extensive hands-on experience with Cisco, Huawei, Juniper and Nokia networking technologies.
He has trained thousands of networking students worldwide through IPCisco.com, Udemy, books, labs, quizzes, and educational content across multiple social media platforms.
IPCisco.com | Best Route to Your Dreams
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