IPv4 and IPv6 are the two versions of the IP or Internet Protocol. IP is a core component of the Internet Protocol Suite and is primarily responsible for addressing and routing packets of data so that they can travel across networks and reach their intended destination.
While IPv4 has been the basis of the internet for decades, IPv6 was developed as a successor to address the primary limitation of IPv4, the shortage of available IP addresses due to the rapid growth of devices connected to the internet.
In this article, we will take a quick look at each protocol, their origins and differences and their relevance on the internet of today and tomorrow.
What is IPv4?
IPv4 was introduced in 1981 and is the foundational protocol of the modern internet. It was created by engineers primarily working for the Internet Engineering Task Force (IETF) and DARPA (Defense Advanced Research Projects). It was designed with a maximum of ~4.3 billion IP address permutations. These addresses can be categorized into 3 different groups:
Public IP address space which organizations own and can route on the internet, Private or internal only IP address space which can never be routed on the internet, and Reserved IP address space for things like loopbacks and multicast.
To control and document who owns what, IANA or the Internet Assigned Numbers Authority was created as the global governing body. Five Regional internet registrars were subsequently created: ARIN for North America, LACNIC for Latin America and Caribbean regions, RIPE for Europe, AFRINIC for Africa and APNIC for Asia Pacific territories.
IPv4 addresses are 32-bit numbers, always expressed in decimal format as four numbers separated by dots, known as “dotted decimal notation”; an example is 192.168.1.1. Using Classless Inter-Domain routing (CIDR) an IP address is always a member of a much larger subnet or block of addresses. For example, a /24 network has 256 addresses and the sizes go all the way up to a /8, which has 16,777,216 addresses.
Due to the supply limitations, the registrars started restricting the assignment of new subnets to organizations in 2010, and over the next few years supply was completely exhausted.
Was there an IPv5? Yes, there was, but it was never approved as it had the same 32-bit address space limitations as IPv4.
What is IPv6?
Released in 1998, IPv6 offers a mind-boggling number of IP addresses, 340 undecillion to be precise. If you are not familiar with an undecillion, let alone 340 of them, let’s try 340 trillion trillion trillion addresses. Even if every person on the planet was assigned the equivalent of the entire IPv4 address space that barely makes a dent in the total IPv6 supply.
IPv6 achieves this vast number of IP addresses by using a 128-bit format rather than the legacy 32-bit one. As a result, the format of the IP address changes to a hexadecimal format separated by colons, 192.168.1.1 versus the 128-bit v6 address 2001:0DB8:85A3:0000:0000:8A2E:0370:7334. The leading zeros can be omitted, and often the consecutive zeros within can be removed from the v6 address to form a compressed address of 2001:db8:85a3::8a2e:370:7334. Despite the many advantages of IPv6 which we’ll come to below, this highlights its primary disadvantage, the understandability and readability of the IP address by us humans.
What are the Differences Between IPv4 and IPv6?
Some of the most notable differences between IPv4 and IPv6 are:
- No geographical limitations, when IPv4 was created, ~50% was reserved for the United States. There are no such restrictions with IPv6.
- IPv4 is still the most adopted version of the IP protocol.
- IPv6 addresses are much longer, and more complex, which means they are difficult to understand and harder to remember.
- IPv6 includes built-in QoS.
- IPv6 mandates IPsec.
- IPv6 eliminates (much of) the need for NAT or Network Address Translation.
- IPv4 – IPv6 Dual Stack leads to a more complex configuration and on-going management.
- Multicasting is part of the basic specification of IPv6, while it is optional in IPv4.
- Mobile IPv6 (MIPv6) is a significant enhancement as mobile devices such as cell phones and IoT devices can maintain their IP address across different networks.
| Feature | IPv4 | IPv6 |
| IP address length | 32-bit | 128-bit |
| Number of IP addresses | 4.3 billion | 340 undecillion |
| Header Length | From 20 to 60 bytes | 40 bytes |
| Address types | Unicast, multicast, broadcast | Unicast, multicast, anycast |
| DNS | A record. | AAAA or quad-a record |
| Local address management | Address Resolution Protocol (ARP) | Neighbor Discovery Protocol (NDP) |
| Address configuration | Manual or DHCP | Manual, SLAAC, DHCPv6 |
| Security | IPsec optional | IPsec mandatory |
| Fragmentation | Carried out by routers and the sending hosts | Carried out only by the sending hosts |
| Packet flow identification | Not available | Available |
| Router Discovery | Optional | Mandatory |
| Checksum field | Available | Not needed |
| VLSM support | Available | Available |
Which is faster – IPv4 or IPv6?
In theory, IPv6 is the faster protocol due to its lack of NAT, more efficient routing, reduced fragmentation, and native QoS support.
However, is it an order of magnitude faster? No. In reality, the speed difference between v4 and v6 will depend on network configurations, the internet backbone itself, hardware and a wealth of other factors.
Similar Features of IPv4 and IPv6
- Both are used to uniquely identify devices connected to a network
- Both support VLSM or Variable Length Subnet Masking
- Both come with error checking and packet fragmentation mechanisms to ensure reliable data transmission
- Both have broadcasting and multicasting capabilities
- Both offer DHCP capabilities
- Both offer DNS, although DNS64 operates a little differently when the client is IPv6 Native
Advantages and Disadvantages of IPv4
The primary advantages of IPv4 are that it’s seemingly been around forever, and people are comfortable with it despite its complexities and limitations. Plus, when a network incident occurs it’s easy to recite the IP address of a device to colleagues on a conference call.
Pros:
- Widespread adoption
- Simple and easy to remember IP addresses
- Mature infrastructure
- NAT, which helped conserve public IP addresses
- Compatibility
Cons:
- Limited address space
- Fragmented IP address management
- Security limitations
- NAT complexity
- Fragmentation and packet size
Advantages and Disadvantages of IPv6
The advantages of IPv6 are very clear, but the disadvantages aren’t to do with the protocol itself. They relate towards the journey of deploying IPv6 within your or any other organization.
Pros:
- Larger address space
- Enhanced security
- Better routing efficiency
- Improved Quality of Service
- Efficient multicasting
Cons:
- Transition complexity and dual stack
- Transition cost
- Harder to understand addressing
- Compatibility issues
- Learning Curve
Real-World Applications and Adoption
Recent statistics state that approximately 44% of the global internet infrastructure supports IPv6, and around 25% of all websites. Therefore, in the 2+ decades since it was created, why has IPv6 adoption been so slow? The answers are very simple, cost, time and need.
- Cost can be described as any infrastructure investment required to support IPv6, the cost of highly complex transformation and modernization programs, the costs of change and the cost of upskilling the IT teams doing the work. In a 6-4 Dual Stack world, cost can come from increased complexity of managing and troubleshooting both protocols. Cost can lastly be the procurement of additional public IP address space.
- Time because these highly complex transformation programs are lengthy in very interconnected always on IT environments.
- Need is an easy one once the drivers for considering an IPv6 migration are understood.
Taking advantage of IPv6 is very important for a great many industry segments, especially those with a burgeoning need for public IP address space.
| Example Industry | IPv6 Solutions |
| Internet of Things (IoT) – billions of connected devices such sensors, wearables, smart home and industrial equipment. |
|
| Telecom and cellular operators – to support the ever-increasing number of smart phones, while reducing their dependency on CGNAT. | |
| Smart Cities – mass deployment of sensors, cameras, traffic management systems and utilities. | |
| Automotive Industry – mass deployment of Vehicle-to-Vehicle (V2V) and Vehicle-to-Infrastructure (V2I) communication |
What is Dual Stack, and How Does it Help?
In the transition of an organization to IPv6, dual stack is a significant network configuration aid in that journey. Dual stack simply means that a device can have both IPv4 and IPv6 addresses, enabling it to operate in both networks simultaneously.
Without delving in depth into ‘how to do an IPv6 transformation’, in the past an organization had their end users, middleware and applications servers across a few network zones (some internet facing, some not). In those days, intra-application traffic was minimal. As a result, changing an IP address on an application and its backend elements was relatively simple because that applications didn’t talk to another one.
In today’s world of big data, data lakes and warehouses, real-time analytics, and APIs, everything talks to everything else, and the changing of an IP address can turn into a massive exercise with significant risks. Therefore, an IPv6 network schema is created and laid alongside the IPv4 one. IPv6 addresses are assigned to the network areas you want to be dual stack. DNS64 is created along with NAT64 ingress and egress points. Intra application traffic can then over time be migrated to the IPv6 layer without interrupting any applications still talking to a particular application on IPv4.
Running Dual stack is more complex and time intensive because two IP protocols are running, being managed and troubleshot side by side, as well as multiple security perimeters. There also can be increased resource consumption on devices due to the increased processing required.
Should You Transition from IPv4 and IPv6?
The short answer is yes, you should. Some organizations can do this relatively quickly, though it could take others many years and many technology transformations. There will of course be organizations who simply don’t have the need and will continue to use the internal network 10.0.0.0/8 and NAT with an ISP-provided subnet or their own /24 to get to the internet and access their cloud workload.
All the big 3 cloud service providers have started charging for the use of their public IP addresses in one form or another. For organizations with substantial presences on these platforms, the monthly charge may soon become too big to ignore and may force a move away from mass usage of dual stack to native IPv6 where possible.
If you are building from greenfield, then becoming IPv6 centric from the start will be an advantage.
In summary, there are too many technological advantages to IPv6 to ignore.
Why Should You Keep IPv4?
Continuing to own IPv4 addresses can be beneficial for several reasons; primarily, the global prevalence and compatibility of it. The need of dual stack and thus IPv4 addresses helps ease the transition to IPv6 at your own pace. As not every organization or industry segment may have plans to migrate to IPv6, retaining IPv4 may be a requirement to meet those industry standards, compliance requirements or customer expectations.
However, due to the scarcity of IPv4 addresses, their financial value has risen too, so it is highly recommended to use IPv4 only in parts of the environment where it is required.
Learn More About Kalorama
Kalorama Group was founded in 2011 at the dawn of the IPv4 market and is one of the industry’s most experienced and credentialed transaction agents in the world. Kalorama has sold more than $1.4 billion worth of IPv4 addresses. Kalorama has extensive experience and specialization in IPv4 address transactions ranging from a single Class B to multi-million address offerings. Our dedicated staff is experienced in complex sales, consulting, technology, policy and project management.
Kalorama is one of the three original registered brokers in the American Registry for Internet Numbers (ARIN). We were the first registered broker in European IP Networks (RIPE) and the Asia Pacific Network (APNIC).
We listen closely to our clients to understand their unique needs and serve as a dedicated resource before, during and after the formal engagements. Contact Kalorama to discuss any IP address needs you have. Whether buying, selling, or leasing we are here to help.
