IPv6 Covered Address Range

[johnlloyd_13]

hi,

i'm still very new to IPv6 implementation. just got a change request to modify a LAN IPv6 address. could someone enlighten me how

2001:BB9:7304:1000::1/64 (not real IPv6 address) is under or from a big chunk of 2001:BB9:7304::1/48 (or is it the other way around)? thanks in advance!

[Michael Vincent · Accepted solution]

You would agree that:

172.16.100.1 /24

is under

172.16.0.0 /16

correct?

IPv6 is the same but with longer "octets" (sedectets) and more of them making longer masks.

2001:bb9:7304:: /48

contains ALL networks and addresses from:

2001:bb9:7304:0000:0000:0000:0000:0000

to

2001:bb9:7304:ffff:ffff:ffff:ffff:ffff

Split it at the /48 boundary, and you have:

2001:bb9:7304 | 0000:0000:0000:0000:0000

2001:bb9:7304 | ffff:ffff:ffff:ffff:ffff

Maybe it's easier to see now that surely, 2001:bb9:7304:1000:: /64 falls within that range:

2001:bb9:7304:0000:0000:0000:0000:0000 /64

2001:bb9:7304:0001:0000:0000:0000:0000 /64

[...]

2001:bb9:7304:0fff:0000:0000:0000:0000 /64

2001:bb9:7304:1000:0000:0000:0000:0000 /64 (your network)

2001:bb9:7304:1001:0000:0000:0000:0000 /64

[...]

2001:bb9:7304:fffe:0000:0000:0000:0000 /64

2001:bb9:7304:ffff:0000:0000:0000:0000 /64

[Deepak Ambotkar]

Michael is correct..

Regards,

Deepak

[johnlloyd_13]

Michael,

Thanks for your clear response! It makes sense to me now.

I guess I'll need more exposure and experience on IPv6.

Cheers!

Sent from Cisco Technical Support iPhone App

[cadet alain]

Hi,

this is same concept as CIDR  notation for IPv6 so /64 is a subnet of /48.

Regards.

Alain

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