TCP/IPv6 Configuration and Management Manual (G06.24+)

IPv6 Fundamentals
HP NonStop TCP/IPv6 Configuration and Management Manual—524523-008
A-3
Types of Addresses
This address typically consists of a 64-bit prefix followed by a 64-bit interface ID as
shown in Figure A-2:
An interface ID identifies an interface on a link. The interface ID must be unique on a
link, but can also be unique over a broader scope. In many cases, an interface's ID is
derived from its link-layer address. The same interface ID can be used on multiple
interfaces on a single node.
According to RFC 2373, most prefixes must have 64-bit interface identifiers. For 48-bit
MAC addresses, the interface identifier is created by inserting the hexadecimal values
of 0xFF and 0xFE in the middle of the address and inverting the universal/local bit (bit
7) in the resulting 64-bit address. Figure A-3 on page A-4 shows how this process
works.
Figure A-1. Unicast Node Address
Figure A-2. Prefix and Interface ID
Node Address
0 127
VST144.vsd
0 127
VST145.vsd
64 bits 64 bits
Prefix Interface ID