Ipv6

sina2011

Hi Guys,

Hope everyone is well,

Just had a quick question trying to wrap my head around ipv6 subnetting.

If you had a network address of lets say 2343:2155:1266:1235::/64

1.How would you write the subnets down. (range of subnets for example
in ipv4 it would be like 192.168.4.0
192.168.8.0 etc

2.How do you find the increments for the subnets.

Thanks.

fredrikjj

The simple approach is to subnets based on the hextet boundary. You could just do:

2343:2155:1266:1235:0001::/80
2343:2155:1266:1235:0002::/80
2343:2155:1266:1235:0003::/80
...
2343:2155:1266:1235:ffff::/80

That gives you 65,535 subnets (actually, 1 less because I didn't use the 0000 subnet). The problem is that you now have a 48 bit host portion, which doesn't support autoconfiguration. On links that you manually configure, this doesn't matter though. The more common approach is to have a /48 and then use the fourth hextet to subnet.

You might have 2343:2155:1266::/48 and do same thing as above:

2343:2155:1266:0001::/64
2343:2155:1266:0002::/64
2343:2155:1266:0003::/64

If you don't want to use an entire hextet for subnetting you need to be more careful, but as long as you don't subnet within one of the "nibbles" (4 bits representing a hex digit) it's pretty easy.

sina2011

thanks for you reply.

so if you fill up the first octect how do you move onto the other one thats something i dont get?

I see in your network ranges you are incrementing by 1 shouldnt you increment the same way in ipv4 if so how do you find the increment im just abit confused with ipv6.

thanks.

fredrikjj

I don't understand your questions.

networker050184

Break it into binary and it's the same thing as IPv4.