IPv6 Configuration Guide K/KA/KB.15.15

Table 7 Mask for configuring a single authorized IPv6 manager station (continued)
8th
block
7th
block
6th
block
5th
block
4th
block
3rd
block
2nd
block
1st
block
D37CFEB617FF24400000000DB82001Other authorized IPv6 addresses
D37EFEB617FF24400000000DB82001
D37FFEB617FF24400000000DB82001
Table 2 (page 56) shows an example in which a mask is applied to the IPv6 address:
2001:DB8:0000:0000:244:17FF:FEB6:D37D/64. The specified mask
FFFF:FFFF:FFFF:FFF8:FFFF:FFFF:FFFF:FFFF configures eight management stations as
authorized IP manager stations.
In this example, the IPv6 mask is applied as follows:
• Eight management stations in different subnets are authorized by the value of the fourth block
(FFF8) in the 64-bit prefix ID (FFFF:FFFF:FFFF:FFF8) of the mask. (The fourth block of
the prefix ID is often used to define subnets in an IPv6 network.)
The binary equivalent of FFF8 that is used to specify valid subnet IDs in the IPv6 addresses
of authorized stations is 1111 1111 1111 1000.
The three "off" bits (1000) in the last part of the this block (FFF8) of the mask allow for eight
possible authorized IPv6 stations:
2001:DB8:0000:0000:244:17FF:FEB6:D37D
2001:DB8:0000:0001:244:17FF:FEB6:D37D
2001:DB8:0000:0002:244:17FF:FEB6:D37D
2001:DB8:0000:0003:244:17FF:FEB6:D37D
2001:DB8:0000:0004:244:17FF:FEB6:D37D
2001:DB8:0000:0005:244:17FF:FEB6:D37D
2001:DB8:0000:0006:244:17FF:FEB6:D37D
2001:DB8:0000:0007:244:17FF:FEB6:D37D
• Each authorized station has the same 64-bit device ID (244:17FF:FEB6:D37D), because
the value of the last four blocks in the mask is FFFF (binary value 1111 1111).
FFFF requires all bits in each corresponding block of an authorized IPv6 address to have the same
"on" or "off" setting as the device ID in the specified IPv6 address. In this case, each bit in the
device ID (last four blocks) in an authorized IPv6 address is fixed and can be only one value:
244:17FF:FEB6:D37D.
Table 8 Mask for Configuring Authorized IPv6 Manager Stations in Different Subnets
Manager- or operator-level
access
8th
block
7th
block
6th
block
5th
block
4th
block
3rd
block
2nd
block
1st
block
In this example, the IPv6 mask
allows up to four stations in
different subnets to access the
switch. This authorized IP
manager configuration is useful
if only management stations are
specified by the authorized
IPv6 addresses. For how the
bitmap of the IPv6 mask
determines authorized IP
manager stations, see fix this
— Example of How an ACL
Filters Packets —
FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFIPv6 mask
D37DFEB617FF24400000000DB82001
IPv6
address
About using a mask to configure authorized management stations 65