[ppml] Policy Proposal 2005-9: 4-Byte AS Number

Michael.Dillon at btradianz.com Michael.Dillon at btradianz.com
Tue Dec 20 09:30:34 EST 2005

> While it is true that there were a few comments of this nature, the vast
> majority of respondents who commented on this did seem to favor the use
> of the decimal and segmenting the AS number into 16 bit chunks for
> human readability.  I know you don't agree, but, I think there was a
> strong enough majority to call it consensus.

Why must you butcher the English language in this way?
Consensus is not the same as majority. In fact, I went
to Google and looked for "consenus majority". The first
result has this sentence in section 5 of the intro:

   So far, unanimity or consensus has been contrasted 
   with majority decisions

Read this if you are interested.

If someone would take the trouble to count the positions
in the emails, I think they would find that there is no
"vast majority" since there is not even a "vast" number
of people commenting. In addition, a number of people 
speaking in favor of the dot were doing so to get rid
of the ambiguity of the colon notation. 

This is an entirely separate question from the question
of introducing a special notation in the first place.
It's not a simple binary partition of positions and 
I don't believe the discussion demonstrated any significant
support for any of the positions discussed. The discussion
raised serious questions:

   Should there be a special notation for AS numbers
   greater than 65535?

   Should a dot be preferred to a colon in such a 
   special notation?

However, the discussion did not decide the answers to
these questions.

> > Is the number 0.63535 a valid AS number?
> yes

How can you tell?

> > What about 0.65553?
> I would say that it is equally valid to as an IP address.

Huh? Everyone knows that is not a valid IP address 
because each segment is an 8 bit number which cannot
be greater than 255.

> Technically, I suppose, an argument could be made that it is valid, but,
> I doubt most parsers would treat it the way you would expect.

The point is that big numbers, such as the maximum unsigned
representation of 16 bits, are not terribly intuitive, not
as easy for people to remember and understand as 256, and not
as easy to figure out when the question is put to you about the 
validity of a number. People can understand 256 possibilities 
because you can almost visualize them and millions of people 
have seen illustrations of tables of 256 eight-bit character
codes. The same cannot be said for 16 bit codes. In addition,
millions of people know that the maximum 16 bit integer is 
32,767 but that is not the same as the maximum 16 bit positive
number used in the definition of an AS number.

> > When the dot notation was introduced for IP addresses,
> > they marked an important bit boundary that was a fundamental
> > part of the IP address. The 32 bit identifier was divided
> > into a NETWORK portion and a HOST portion. This division
> However, there's three dots and only one boundary for any given
> address.  I don't know whether you'll accept this or not, but,
> I do believe that a portion of the thinking of using dotted quads
> was to make IP addresses more human-readable and reduce human
> audio transmission/reception errors.

That was at a time before the existence of text messages
and email and IM and ...

> I'll also point out that dotted quad did not go away with the
> advent of CIDR

That's not the point. The point is that it CAME IN for
a good reason related to the structure of IP addresses 
and there use in subnet and host addressing. There is
no structural and usage related reason to INTRODUCE a
new AS number notation superceding the old one.

> IP addresses today are simple integers as well.

Not so. That's why we have slash notation. There is
still an important distinction between network and
host addresses even though CIDR allows for more variation
in network sizes.

>  Either way, the position of the dots
> in IP addresses is no longer related to that structure, but, the dots 
> not moved or been abandoned.

Exactly! When IPv4 subnetting was changed by CIDR, we
stayed with the convention of representing IPv4 address 
as they always had been. That's why I believe we should
also STICK WITH THE CONVENTION of representing AS numbers
as simple decimal integers with optional prefixes like
AS or ASN.

There is no need to change things at all.

There is no need to write AS number 65536 as AS 65536 and AS 1.0
There is no need to explain to people that 1.324 is not actually
a real number but it is a 32 bit integer.

--Michael Dillon

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