IP addressing question

[Lewis Quin]

When talking about IP address, each of the bits within an octet has a value depending on its location, for example the bit all the way on the right has a value of 1, and the bit all the way on the left has a value of 128 is there a term used to describe the values each bit gets when switched on?

[Jon Marshall]

Not sure what you mean by a term for when it is switched on.

Do you mean in terms of IP addressing or something else ?

With IP addressing you can use the / notation but I'm not sure that is what you are asking.

Jon

[Lewis Quin]

bits are either enabled or disabled, i.e. 1 or 0.. my question was is there a term to describe the value assigned to each bit. i.e. one bit when enabled has a value of 128, when another may have 64

128 64 32 16 8 4 2 1 

0      0   0   0  0 0 0 0 

[Jon Marshall]

I don't understand what you mean by "term".

If you simply mean value then just add up all the bits that are turned on eg.

0 1 0 0 1 0 0 0  would be 64 + 8 = 72

but again I don't think I am answering your question.

Jon

[Lewis Quin]

Is there a term to describe the values assigned to each of the bit placements

[Jon Marshall]

Do you mean if someone said to you "Lewis the umpty bit is on" you would know that was the 7th bit from the left or the one with a value of 64 ?

Then no, there are no umpty bits.

The only terms I know are the most significant or high order bit and the least significant or low order bit which for networking equate to the leftmost bit and the rightmost bit.

Jon

[Lewis Quin]

not quite, I was looking for a term that would illustrate the fact that each bit has a different value based on its position/order.

[Joseph W. Doherty]

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Posting

According to Wiki, IPv4 uses MSB 0 bit numbering.  So you can refer to any bit by its number, 0..31 (left to right).

[Jon Marshall]

If someone said to me the value of that byte is 224 I  would know automatically that the first 3 bits from the left were turned on.

Is that what you mean ?

Jon

[Jon Marshall]

 -

[Joseph W. Doherty]

Disclaimer

The Author of this posting offers the information contained within this posting without consideration and with the reader's understanding that there's no implied or expressed suitability or fitness for any purpose. Information provided is for informational purposes only and should not be construed as rendering professional advice of any kind. Usage of this posting's information is solely at reader's own risk.

Liability Disclaimer

In no event shall Author be liable for any damages whatsoever (including, without limitation, damages for loss of use, data or profit) arising out of the use or inability to use the posting's information even if Author has been advised of the possibility of such damage.

Posting

I cannot think of any term for switching on (or off) individual bits, but from your question, I wonder if, to you, it's a little unclear what an IP address actually is, and what octet notation actually is.

An IPv4 address is a 32 bit number.  The octet notation splits the 32 bit number into four 8 bit bytes and represents the value of each of those 8 bit byte using its decimal value.

e.g.

10000000 00000000 00000000 00000001 = 128.0.0.1

00000001 00000010 00000011 00000100 = 1.2.3.4

00000011 00001111 00111111 11111111 = 3.15.63.255