[ppml] Policy Proposal 2005-9: 4-Byte AS Number
bmanning at vacation.karoshi.com
bmanning at vacation.karoshi.com
Tue Dec 20 18:48:39 EST 2005
On Tue, Dec 20, 2005 at 03:28:36PM -0800, Owen DeLong wrote:
> > 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?
> No. However, once we start using 32 bit AS numbers, having a divided
> notation for them is desirable as an adjunct to human readability.
> Thus, I favor the future notation of existing AS numbers as 0.ASN
> and AS numbers in excess of 65535 as A.B where A=int(ASN/65536)
> and B=ASN mod 65536.
> > Should a dot be preferred to a colon in such a
> > special notation?
> Absolutely. Colons are ambiguous with current use of community notation.
hum... human readability is the only factor here?
i'd settle for a '-' or even '*' or... '#' ... perhaps 'x'
would be a fine choice.
> > However, the discussion did not decide the answers to
> > these questions.
> OK, well... I guess there will be more discussion on this. You now have
> my votes on these two questions.
> >> > Is the number 0.63535 a valid AS number?
> >> yes
> > How can you tell?
> What do you mean?
> 0.63535 is the 32 bit representation of what is currently 63535.
> There is no difference between 0.63535 and 63535.
> >> > What about 0.65553?
> >> I would say that it is equally valid to 0.0.0.384 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.
> I'm betting most of the people who know that 32767 is the maximum
> 16 bit integer are well aware that 65535 is the maximum unsigned
> 16 bit integer.
> >> 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 ...
> What's your point? As someone who works in an actual NOC, I can
> guarantee you that IP addresses and ASNs are still exchanged
> in telephone conversations on a regular basis today.
> >> 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.
> I guess we'll have to agree to disagree on this. I think that
> the readability issue is a good reason.
> >> 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.
> Please explain the purpose of the dots in IP addresses as
> it relates to this? Please explain the purpose of the :s
> separating 16 bit chunks in IPv6 addresses as it relates
> to this. It just doesn't fit.
> >> Either way, the position of the dots
> >> in IP addresses is no longer related to that structure, but, the dots
> > have
> >> 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.
> I suppose that when the US went from phone numbers like BR549 to
> NPA-NXX-SUFX, you would have preferred to continue representing
> those phone numbers as two letters followed by a larger string of
> > 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.
> Need is an interesting term. However, I would argue that there is
> also no need to make people look at ASNs like AS129391243 and that
> it is much better to, instead, represent that as AS1974.23179.
> Just as I prefer +1.408.555.1212 to 14085551212 and prefer
> 95121-1520 to 951211520 and 123-45-6789 to 123456789. Sure,
> there is some structural significance in each of these cases,
> but, said structure is not important to most common usages of
> those data. Instead, it is primarily there to improve
>  These numbers are, respectively, NANP (North America) Telephon Number,
> united States Postal code, United States Social Security Number.
> If it wasn't crypto-signed, it probably didn't come from me.
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