IPv6 addressing support in MainView for IP
IP version 6 (IPv6) is a version of the Internet Protocol, designed as the successor of IP version 4 (IPv4).
The biggest change in IPv6 is its expanded addressing capability. The IP address in IPv4 is 32 bits or 4 bytes long. The IP address in IPv6 is 128 bits or 16 bytes long. MainView for IP supports IPv6 by providing expanded IP addresses.
IPv4 addresses are represented in dotted decimal format. The 32 bit address is divided at 8 bit boundaries. Each of the 4 sets of 8 bits is converted to its decimal (base 10) equivalent, and the sets are separated from each other by a period (or stop).
For IPv6, the 128 bit address is divided at 16 bit boundaries. Each 16 bit block is converted to a 4 digit hexadecimal number (base 16, 0-F), and the blocks are separated from each other by a colon. Here are two examples of IPv4 and IPv6 uncompressed and compressed addresses.
To simplify IPv6 addresses, any consecutive sequence of 16-bit blocks that is set to 0 in the colon hexadecimal format is compressed to '::' (two colons) as shown in the following example:
The following guidelines apply:
- Zero compression can be used only once in an IPv6 address.
- Only one null string can be replaced with a double colon, which can then be filled out to retrieve the original long form address.
- If there are two null strings, only one can be compressed. If both were compressed, it would be impossible to determine the length of each string, and the address would be ambiguous.
Another form, which is sometimes more convenient in dealing with a mixed environment of IPv4 and IPv6 nodes, is:
x:x:x:x:x:x:d.d.d.d.
The value of x represents the hexadecimal values of the six high-order 16-bit pieces of the address, and d represents the decimal values of the four low-order 8-bit pieces of the address.