IPV6 Training Books

Tue Apr 5 00:59:31 UTC 2011

In message <690D7D20D2507C44BA8066926B2009890867FA at ES1002.ic-sa.com>, Michael R
uiz writes:
> Hello All,
> 
>                 I am looking for some good reading material to get a better=
>  understanding of IPV6.  I know how to convert HEX into decimal format.  Wh=
> at I am looking for is how to under the CIDR notation and break them out in=
> to subnets.   Thank you in advance.

If you think in hex its straight forward to do CIDR in IPv6.  There
are only three groupings on a non nibble boundaries.  You also
display the entire 128 bits with the least significant bits set to
zero.  The :: notation is used to shorten the displayed address.

e.g for a /57, /58 and /59 with leading bits of 2001:23bc:fe8d:b200::/56
you would have.

/57	{0,1,2,3,4,5,6,7} {8,9,a,b,c,d,e,f}
	2001:23bc:fe8d:b200::/57
	2001:23bc:fe8d:b280::/57
/58	{0,1,2,3} {4,5,6,7} {8,9,a,b} {c,d,e,f}
	2001:23bc:fe8d:b200::/58
	2001:23bc:fe8d:b240::/58
	2001:23bc:fe8d:b280::/58
	2001:23bc:fe8d:b2c0::/58
/59	{0,1} {2,3} {4,5} {6,7} {8,9} {a,b} {c,d} {e,f}
	2001:23bc:fe8d:b200::/59
	2001:23bc:fe8d:b220::/59
	2001:23bc:fe8d:b240::/59
	2001:23bc:fe8d:b260::/59
	2001:23bc:fe8d:b280::/59
	2001:23bc:fe8d:b2a0::/59
	2001:23bc:fe8d:b2c0::/59
	2001:23bc:fe8d:b2e0::/59

Note the last nibble before the :: is 0 and is there so that the
final bits are all zeros.  The following all represent the same
cidr block.

	2001:23bc:fe8d:b2e0::/59
	2001:23bc:fe8d:b2e0:0000:0000:0000:0000/59
	2001:23bc:fe8d:b2e0:0:0:0:0/59

Normally you just assign /64 subnets and delegate address blocks
on nibble boundaries to end customers, e.g. /48, /52, /56 or /60.
This means that end customers don't need do deal with cidr block
if they don't want to.  They can just route individual /64.

> MAR.
> 
-- 
Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742                 INTERNET: marka at isc.org