An ISP is normally allocated a /32 block.
In Singapore, One of the block issued to Singtel is 2001:0C20::/32
| n bits | m bits | 128-n-m bits |
+-----------------------------+---------------+-------------------------------+
| global routing prefix | subnet ID | interface ID |
+-----------------------------+---------------+-------------------------------+
An organization is often allocated a /48 block of IPv6 address space.
Let's use 2001:0C20:A::/48 10th group in the subnet assigned to ISP
The remaining 16 bits of the first half 64 bits will give 65536 /64s
Let's use 0000 for loopback address
2001:0C20:A:0000:0000:0000:0000:0000/64
Router Loopback Addresses
Router loopback addresses are /128 bit host routes
2001:0C20:A:0000:0000:0000:0000:0000/64
Each router loopback address is indicated by its Router # (y):
2001:0C20:A:0000:0000:0000:0000:0001/128
2001:0C20:A:0000:0000:0000:0000:0002/128
2001:0C20:A:0000:0000:0000:0000:FFFE/128
2001:0C20:A:0000:0000:0000:0000:FFFF/128
Point-to-Point Addresses
Point-to-Point are links between only two nodes.
For such networks, we could use one specific set of networks allocated
from the prefix 2001:0C20:A:F000:0000:0000:0000:0000/52
Examples of possible Point to Point subnets:
Point-to-Point Link 1
2001:0C20:A:F001:0000:0000:0000:0001/64
2001:0C20:A:F001:0000:0000:0000:0002/64
...
Point-to-Point Link 10
2001:0C20:A:F00A:0000:0000:0000:0001/64
2001:0C20:A:F00A:0000:0000:0000:0002/64
Server, Printers Subnet Assignment (Static IP)
For such networks, we could use one specific set of networks allocated from the prefix 2001:0C20:A:E000:0000:0000:0000:0000/52
These are examples of possible server subnets:
2001:0C20:A:E001:0000:0000:0000:0000/64
2001:0C20:A:E002:0000:0000:0000:0000/64
...
2001:0C20:A:EFFE:0000:0000:0000:0000/64
2001:0C20:A:EFFF:0000:0000:0000:0000/64
General End-Node Subnets
There are a a few ways you could subnet your end node subnets:
| n bits (48) | b(8) | s(8) | 128-b-s bits (64) |
+-----------------------------+--------------+----------------------------+
| global routing prefix | bldg | Lvl | interface ID |
+-----------------------------+--------------+----------------------------+
OR
| n bits (48) | v(16) | 128-v bits (64) |
+-----------------------------+----------------+----------------------------+
| global routing prefix | VLAN ID | interface ID |
+-----------------------------+----------------+----------------------------+
Building addresses are summarized as: 2001:0C20:A:bb00:0000:0000:0000:0000/56
Level addresses are: 2001:0C20:A:bbll:0000:0000:0000:0000/64
Therefore, Building 45, Level 7 would be: 2001:0C20:A:4507::/64
