[CentOS] IP6 Anyone?

David Sommerseth dazo at users.sourceforge.net
Sun Feb 27 12:00:47 UTC 2011


On 27/02/11 06:46, Always Learning wrote:
> Octets
>
> Thanks for pointing-out my misunderstanding.
>
> I'll remember 2 octets are really 2 characters (IBM's bytes) = 2 digits,
> 4 octal numbers or 4 hexadecimal numbers.

This is a confusing summary.

3 bits = 1 octal number (values 0-7)
4 bits = 1 nibble  (values 0-15 or in hex 0x0-0xF)
8 bits = 2 nibbles = 1 byte or 1 octet (values 0-255 or in hex 0x00-0xFF)

Don't mix in octal numbers, as that's a completely different numeric system 
which is very seldom used nowadays.  Octal numbers are smaller than nibbles, 
which is usually the smallest unit referred to in today's computers.

IPv4 uses 32 bits addresses, hence 4 bytes (4 bytes * 8 bits per byte = 32 
bits).  Organised into 4 "group", separated by dot.  Each "group" contains 1 
byte, where user interfaces uses decimal notation, with values from 0 to 255

IPv6 uses 128 bits addresses, hence 16 bytes (16 bytes * 8 bits per byte = 128 
bits).  Organised into 8 "groups" separated by colon.  Each "group" contains 
of 2 bytes, where user interfaces uses hexadecimal notation, with values 
0x0000 to 0xFFFF.


That's basically it.


kind regards,

David Sommerseth




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