IPv6 address

IPv6 address: xxxx:xxxx:xxxx:xxxx : xxxx:xxxx:xxxx:xxxx
> Each hex character(x) denotes a tuple(4 bits). Two tuples (2 hex characters) denotes 1 byte (8 bits).
> 1st 8 bytes = network address portion.
> 2nd 8 bytes = hosts addresses portion
Mỗi octe = 16bit
Không gian địa chỉ: 2^128 =  ???

1. Link local Address.

+ FE80::/10

+ node on local link can use link-local address to communicate.  They do not need globally unique addresses to communicate

+ when ping to address, need outgoing interface.

+ IPv6 routers should not forward packets that have link-local source or destination addresses to other links

-> This means that packets with link-local addresses cannot be routed between interfaces

2. IPv6 Unique Local Addressing (ULA)

+ FEC0::/10  = ip private in IPv4

+ ULA address are not public routable prefixes on the Internet.

+ The format of the ULA is:

FC00 (7 bits) + Unique ID (41 bits) + Link ID (16 bits) + Interface ID (64 bits)

3. IPv6 Global Aggregatable Addressing

+ start with the binary prefix 001 (2000::/3) range 2000::-3FFF::.

+ use global unicast address, are public allocated and routetable on the internet.

+ 2001::/16 is currently used for allocation.

4. IPv6 EUI-64 Addressing

+  IPv6 host addresses are generated from interface MAC addresses

+  A MAC address is 48-bits and IPv6 host address is 64-bits

+  The extra 16-bits are derived as follows:

>> MAC address 1234.5678.9012

>> Invert the 7th most significant bit (in binary) = 00010010 > 00010000 (thus 12 becomes 10)

= 1034.5678.9012

>> Insert FFFE in the middle

= 1034.56FF.FE78.9012

5.