dslreports logo
 
    All Forums Hot Topics Gallery
spc
uniqs
23

bobrk
You kids get offa my lawn
Premium Member
join:2000-02-02
San Jose, CA

bobrk to noaccess

Premium Member

to noaccess

Re: [ipv6] ipv6 subnetting question

Does the subnetting even do anything? I set up a network with both /64 and /32 and I can see everything.

noaccess
@hosting.com

noaccess

Anon

i just want to know how it is done

tschaefer
@t-dialin.net

tschaefer to bobrk

Anon

to bobrk
said by bobrk:

Does the subnetting even do anything?

Of course!

One /32-net has 32 /64-nets inside.
tschaefer

tschaefer to noaccess

Anon

to noaccess
How do you split subnets in IPv4?

By configuring your routers and hosts.
Sub-netting is nearly the same as in the old protocol.
You have more bits, write the mask-length every time with "/xx" and usually you don't split /64 for LANs.

leibold
MVM
join:2002-07-09
Sunnyvale, CA
Netgear CG3000DCR
ZyXEL P-663HN-51

leibold to tschaefer

MVM

to tschaefer
said by tschaefer :

One /32-net has 32 /64-nets inside.

Just a few more then 32

How does approximately 4 billion sound ?

A /32 prefix has 32 bits left over for subnetting (assuming /64 subnets). 32 bits allow for 4294967296 subnets.

tschaefer
@t-dialin.net

tschaefer

Anon

Sorry 2^32 subnets.

cablegeek01
join:2003-05-13
USA

2 recommendations

cablegeek01 to noaccess

Member

to noaccess
Take your 2001:db8::/32, and start splitting off /64 networks.
Remember, an IPv6 address has 64b for the network prefix, and 64b for the interface ID (host), so:
x:x:x:x:y:y:y:y = x for network, and y for interface id (host)

One addressing scheme would be to subnet the /32 by region and local subnet, so you'd have:
x:x:y:z where x is your /32 parent block, y is your /48 region id (0-ffff), and z is your /64 subnet id (0-ffff).

The remaining 64bits are your interface ID (host IP), and will be assigned via SLAAC, or DHCPv6 if you don't opt for static IP addressing.

That gives you 65,000 regions, and 65,000 subnets in each region.

For the below examples, we'll start with region 0, subnets 0 through 2.

Region 0 subnets 0-2
2001:0db8:0:0:0:0:0:0 through 2001:0db8:0:0:ffff:ffff:ffff:ffff =/64 #1
2001:0db8:0:1:0:0:0:0 through 2001:0db8:0:1:ffff:ffff:ffff:ffff =/64 #2
2001:0db8:0:2:0:0:0:0 through 2001:0db8:0:2:ffff:ffff:ffff:ffff =/64 #3 etc

Region 1 subnets 0-2
2001:0db8:1:0:0:0:0:0 through 2001:0db8:1:0:ffff:ffff:ffff:ffff =/64 #1
2001:0db8:1:1:0:0:0:0 through 2001:0db8:1:1:ffff:ffff:ffff:ffff =/64 #2
2001:0db8:1:2:0:0:0:0 through 2001:0db8:1:2:ffff:ffff:ffff:ffff =/64 #3 etc

If you followed it to the end, it would go all the way up to 2001:0db8:ffff:ffff:ffff:ffff:ffff:ffff

Does that make sense?