IBM TS4500, Introduction And Planning Manual

Page: 82 / 218

2001:db8:abcd:0012:ffff:ffff:ffff:ffff
. The portion in bold is called the
network portion of the IP address, or the prefix. The non-bold portion is called the
host portion of the IP address, since it identifies an individual host on the network.
IPv6 addresses
An IPv6 address is eight groupings of numbers:
v
Network address - the first three groupings of numbers (first 48 bits) in the
subnet mask
v
Subnet addrress - the fourth grouping of numbers (the 49th through 64th bits)
in the subnet mask
v
Device address - the last four groupings of numbers (the last 64 bits) in the
subnet mask
For example, in the following IPv6 address:
2001:db8:abcd:0012:0000:0000:0000:0000
The network address is
2001:db8:abcd
, and the subnet address is
12
(using the
short form notation and eliminating the leading zeroes). Together, these two
groupings are the IPv6 prefix . The device address in the example is
0000:0000:0000:0000
.
Each device in the network has a unique device address, but the network address
and subnet address portions of the IPv6 address are the same for every device in
the network. So, the first four groupings of numbers in every IPv6 address remain
constant, and the last four groupings of numbers vary with each device. You can
simplify your list of devices by substituting a prefix-length in place of the device
address portion of the IPv6 address. The prefix-length specifies a range of devices.
It is expressed as a slash (/), followed by an integer between 1 and 128. For
example, a prefix-length of
/64
specified like this:
2001:db8:abcd:0012::/64
tells
the system to divide the network into 64 subnetworks. Each subnetwork contains
1/64th of the devices on the network. Table 22 shows the resulting network ranges
for prefix lengths of IPv6 addresses.
Table 22. Network ranges for prefix lengths of IPv6 addresses .
Expanded notation of IPv6 address at start of the
range
IPv6 address (condensed
notation) IPv6 Address with prefix length Device range in subnetwork
2001:0DB8:ABCD:0012:0000:0000:0000:0000 2001:DB8:ABCD:12:: 2001:db8:abcd:0012::0/64 2001:0DB8:ABCD:0012:0000:0000:0000:0000 -
2001:0DB8:ABCD:0012:FFFF:FFFF:FFFF:FFFF
2001:0DB8:ABCD:0012:0000:0000:0000:0000 2001:DB8:ABCD:12:: 2001:db8:abcd:0012::0/80 2001:0DB8:ABCD:0012:0000:0000:0000:0000 -
2001:0DB8:ABCD:0012:0000:FFFF:FFFF:FFFF
2001:0DB8:ABCD:0012:0000:0000:0000:0000 2001:DB8:ABCD:12:: 2001:db8:abcd:0012::0/96 2001:0DB8:ABCD:0012:0000:0000:0000:0000 -
2001:0DB8:ABCD:0012:0000:0000:FFFF:FFFF
2001:0DB8:ABCD:0012:0000:0000:0000:0000 2001:DB8:ABCD:12:: 2001:db8:abcd:0012::0/112 2001:0DB8:ABCD:0012:0000:0000:0000:0000 -
2001:0DB8:ABCD:0012:0000:0000:0000:FFFF
2001:0DB8:ABCD:0012:0000:0000:0000:0000 2001:DB8:ABCD:12:: 2001:db8:abcd:0012::0/128 2001:0DB8:ABCD:0012:0000:0000:0000:0000 -
2001:0DB8:ABCD:0012:0000:0000:0000:0000
64
IBM TS4500: Introduction and Planning Guide