ISPs in Nepal are introducing IPv6, but what does it really mean?

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The news of top ISPs like Classic Tech and Worldlink moving to IPV6 has been buzzing lately. But what does it really mean? And why is it important that more ISPs start switching from IPV4 to IPV6. Well, worry not cause that’s what we are going to touch upon in this article. We’ll break down the frequently used terms such as IP address and gradually move on to what IPV6 is and why it is important. 

What is an IP address?

How does one know who the sender of a “post letter” is and who is meant for? Obviously, it is through the house address written in the envelope. The addresses specify who the sender is and who is the recipient. And for devices connected in a network, we use IP addresses. 

To be more specific, IP or Internet Protocol specifies the standard format of packets and addressing scheme for devices to communicate over a network. And a device that uses the Internet Protocol is assigned a numerical label, IP address, as an ID to help in its identification over the network. Everything connected to the internet has an IP address, be it a device or a website. 

Internet Protocol Versions

So, it’s clear that anyone who is connected to the internet has a unique IP address. The address is based upon the version of the Internet Protocol that you are using. And no, one does not get to choose the IP version on their own. We use the same protocol that our Internet Service Provider (ISP) uses. 

Currently, there are two versions of the Internet Protocol: IPv4 and IPv6. IPv4 is the most commonly used version of IP. However, there has been a significant increase in the number of users of IPv6. As a matter of fact, Google in 2018 reported that 23.94% (6% increase from 2017) of its users visited the site via IPv6. Now, that was two years ago. That number has significantly gone up since then. However, for now, IPv4 and IPv6 co-exist. But eventually, everything will move to IPv6.

Before jumping into why the migration from IPv4 to IPv6 is needed, let’s first understand what they actually are.


Internet Protocol Version 4 or the IPv4 was developed way back in 1983 for ARPANET. And till date, it is the most widely used IP version out there. While browsing through the internet, you may have come across a number separated by dots such as It’s not gibberish. It is actually the unique address assigned using the IPv4. And it helps a device to be found on the internet.

IPv4 is a 32-bit addressing scheme. That means there are 2^32 (4.3 billion addresses) available. Other than that, some of its other features include numeric addressing, 12 header fields, broadcast support, and checksum fields.

ipv4 vs ipv6 header


Now, let’s come to the newer version of the internet, IPv6, or also referred to as IPng. It is not something that we are eagerly waiting for. Rather it is already out there and has been for quite some time now. It was developed in the late 1990s to replace IPv4.

IPv6 uses a 128-bit addressing scheme. So, theoretically, it has 2^128 (340 undecillion) addresses. Rather than just the numbers, its addresses are represented as hexadecimal (alphanumeric) digits and they are separated by colons. 

IPv4 vs IPv6

Other than the obvious address space difference, there are some other things in which IPv4 and IPv6 differ. For instance, IPv6 supports multicast addressing. That means it allows bandwidth-intensive packets to be sent to multiple destinations simultaneously, thereby reducing the network bandwidth. 

Speed and Security Comparison

The important things to consider while talking about the IP versions are speed and security. Theoretically, IPv6 should be faster than IPv4 because NAT translation is not required. However, IPv4 has existed for a lot of time now, and thus over the years, it has been continuously optimized. As a result, in actual tests, one might not notice a significant speed difference. But as with IPv4, IPv6 too will go through a lot of optimizations and thus should see a significant increase of speed in the future.

Talking about security, IPv6 is equipped with IPSec security protocols and thus is more secure than IPv4. However, IPSec can also be integrated into IPv4, but it is up to your ISP to do that. 

Basically, IPv6 is designed for end-to-end encryption and makes the man-in-the-middle attack more difficult. Furthermore, for secure name resolution, IPv6 uses the Secure Neighbor Discovery (SEND) protocol over the Neighbor Discovery Protocol (NDP). Also, IPv6 has two security headers for data-origin authentication, protection against replay attacks, connection-less integrity, and privacy & confidentiality.

Other Advantages of IPv6

Another major advantage of using IPv6 is that the public signature key can be integrated and thus help to show the proof of ownership. It cannot be done in IPv4 due to its 32-bit addressing scheme. Furthermore, IPv6 eliminates NAT thereby allowing end-to-end connectivity. Lastly, it allows one to belong to many networks simultaneously with a unique address on each one.

Why is migration from IPv4 to IPv6 necessary?

4.3 billion address spaces seem pretty huge, but is it actually though? Since, the boom of the internet in the early 2000s, devices connected to the internet has continued to grow. Thus, the 4.3 billion address space have been quickly used up. 

IPv4 addresses are allocated by IANA to Regional Internet Registries (RIR). And RIR then again allocates these blocks to ISPs. Now, IANA has already given out its last block of IPv4 addresses, which means all the spaces are sold out and there is no room for a new one. Obviously, ISPs can allocate the unused address spaces that they have already bought. However, that is only a limited period solution. Eventually, that is going to run out and thus IPv6 implementation will be a necessity. 

For ISPs to transition to IPv6 from IPv4, they will need to convert their modems and networking gears to IPv6 capable gear. That will incur a lot of costs, but if they want to stay relevant in the market and want their customer base to grow, they will need to switch.

Classic Tech in Nepal, for example, has been working on this migration since last year and currently have switched 80% of their customers to IPv6. Hopefully, other ISPs will opt for a switch soon.

So, using IPv6 cut you off from the web because most sites still use IPv4? Well, that’s not gonna happen as ISPs implement the NAT64 technology. This technology encapsulates IPv4 address into IPv6 address and through that one can easily visit IPv4 websites.

How to know if you are using IPv6

Well, for this, you can visit websites like that allow you to connect to it in different ways. You can click on the links near the top and see if you can connect via IPv6. If not, it is most likely that your ISP has not enabled it. Or it could be that your router does not support it.