IPv6 Addressing
When the IPv4 abode has 32 bits, the IPv6 abode is represented by a (hopefully) great 128-bit number. The abounding IPv6 abode is accounting as eight blocks, anniversary absolute four hexadecimal numbers. These blocks are afar by colons ":". A hex cardinal represents a 4-bit field, so a accumulation of 4 hex numbers represents 16 bits. So we charge accept 8 such groups of numbers to accomplish up the abounding 128 $.25 of the IPv6 address:
x:x:x:x:x:x:x:x
As we will altercate in a moment, abounding types of accepted IPv6 abode implementations absorb a lot of after zeroes in the address. When this happens, there are some advantageous rules that acquiesce us to abridge the address. It's easiest to accept these rules with a accurate example.
Suppose we accept this address:
FEC0:0000:0000:0001:0000:0000:0000:0001/64
We can aboriginal annul all of the aerial adjustment zeroes in anniversary accumulation of four hex numbers.
FEC0:0:0:1:0:0:0:1/64
Then we can alter the longest set of after zeroes with artlessly "::":
FEC0:0:0:1::1/64
This article is now abundant easier to assignment with.
Also agenda that in the example, we accept included the prefix admeasurement /64, at the end of the address. This assemblage is identical to the prefix admeasurement bit calculation acclimated in IPv4 addresses. This is not alone agnate in actualization to the IPv4 CIDR representation of addresses, but it has the aforementioned function, acceptance routers to authorize assorted hierarchical abode summarizations in the network.