Subnetting IPv6 Addresses

This video will look at how to subnet in IPv6. Due to IPv6 having a much larger address space, the process of subnetting is very different from subnetting in IPv4.

IPv6 Subnetting
0:23 Given that IPv6 has a much larger address space then IPv4, 16 bits of an IP Address is dedicated to subnetting. In IPv4, a subnet mask had be used to determine which parts of the IPv4 address would be used to define the network and which parts of the IP Address would be used to define a host on the network. Due to IPv6 having 16 bits dedicated for subnetting, the subnet mask is not required.

Simple IPv6 Subnetting Example
0:58 In this example, the administrator has been given an IPv6 address of 2001:d8b:cad::/48. IPv6 uses a 128 bit address, so this means that the first 48 bits have already being allocated. The next 16 bits are used for the dedicated subnet ID and the last 64 bits are used for the interface ID. The interface ID is configured using DHCP or statically assigned by the node. Administrators are free to configure the subnet ID bits any way they choose. The simplest subnet ID is to have the subnet ID being all zeros. If you want to add another network, change the subnet ID to one. To add another network, change the subnet ID to two and so on. This is a very simple way to allocate subnets. In small networks, this is a good choice for the administrator, as it is not too complicated and is easy to set up.

IPv6 Subnetting Example
2:16 In this example, the subnet ID has been broken into four giving four bits for each part. Working with addresses that are aligned to four bit boundaries makes it easy to work with. This is because the breakdown is aligned with the values in the address. For example, the first value will represent the country. This value ranges from zero to f. So looking at the first value in the subnet ID, this will tell you the country the address has been allocated to. For example, you could have any address starting with zero for America and one for England. The second value in the subnet ID in this example is allocated to state. If we take the American one as an example an address starting with 00 would be America and the first state; 01 would be American and the second state. If we were to look at an address starting with 1. This would mean the address is for England. The first county in England would start with zero, thus the subnet ID would start with 10. The second county would have a value of one meaning the address would be 11. Further bits are allocated to offices and departments. So taking an example subnet ID of 1432 would mean the country is England, the county is the fourth county, the office is the third office and the department in that office would be the second. Working with 4 or 8 bit boundaries makes it easy to work out which network the subnet ID is referring to.

Credits

[aleksandarr.]

I bet I couldn't find a better explanation on internet than this. Thanks a lot!

[Amethyst-ebjp]

Fantastic video! This video was simple enough that a beginner like myself could understand. Thanks!

[ABMA]

The video is amazing, but it will be useful more if we can do the subnetting manually to create more understanding of the moment we need to use the website. I don't know, I get the feeling that subnetting on IPv6 is so complicated and hard to do quickly, that is why programs to calculate and help in terms of subnetting have been introduced.
please clarify and give us a lesson through which we can do the subnetting manually.

[craiglindstrom]

Isn't this really route aggregation rather than subnetting? All networks are /64 as I understand it.

[daniel]

Great video, thanks for the clear and concise explanation.

[TheYeti_]

Hi there just curious why you decided to input the least required number of subnets eg:17 instead of just keying in 32?

[lucasdelmarcel]

Great explanation, this was exactly where I was looking for !!

[sachinramsuran]

Thank you. This is a most helpful video including the link to gestioip

[bcshay]

basically VLSM concept via IPv6 with variable length network prefixes.

[rizwanrafeek]

Thanks a million for sharing this video.

[alfabetony]

am i the first to realize that he said 5 to the power of two is 32, but I think he meant 2 to the power of 5 is 32 it confused me for a bit. Thanks for the video!