please define terms

[Philip J. Nesser II]

Larry Honig supposedly said:
>
> I'm sorry to brutally expse my ignorance of terms, but I may not be the
> only neophyte here so I will do it anyway. What exactly is meant by /24,
> /19, /xx??  It seems that the "buying power" represented must be greater
> as the denominator decreases. Would a /1 allocate all 4 billion IPs?
> How does this map into - lets say - a scheme where I as an ISP would
> like to allocate (in IPv4 syntax) all the numbers between (for example -
> not a real sequence) 99.128.51.0 and 99.128.51.255? Also, under IPv6 how
> would this look? Please give a specific example if possible. Thanks in
> advance.
>

its easiest to work it backwards:

/32     1 address
/31     2 addresses
/30     4 addresses
/29     8 addresses
/28    16 addresses
...
/24   256 addresses (traditional class C)
...
/16 65536 addresses (traditional class B)  (or a block of 256 traditional
                                            Class C's)

so 192/8 means the 65536 traditional class C addresses starting at
192.0.1.0 to 192.255.255.0


your examples would be written as 99.128.51/24


There are countless materials on this but I suggest looking at an RFC
archive and searching for CIDR.  (Try RFC 1518)