網路原理(一) Section 8.1

Subnetting
The solution is to reduce the size of the network to create smaller broadcast domains in a process called subnetting. 

Classful Boundary
分類的邊界

Classless Subnetting
The examples seen so far borrowed host bits from the common /8, /16, and /24 network prefixes. However, subnets can borrow bits from any host bit position to create other masks.

Magic number
讓人模糊的數字

Variable Length Subnet Mask (VLSM)
In all of the previous examples of subnetting, notice that the same subnet mask was applied for all the subnets. 

Global Routing Prefix
The IPv6 global unicast address normally consists of a /48 global routingprefix, a 16 bit subnet ID, and a 64 bit interface ID.