Re: [Idr] new ID on expansion of private use ASN range

[Jeffrey Haas <[e-mail]>]

Jon,

On Mon, Jul 02, 2012 at 09:55:21PM -0400, Jon Mitchell wrote:
> > I suggest that we leave 65535 alone as a reserved AS.
> 
> [JM] I think it should be clarified either way, and I think adding it to
> the private use ASN range with this draft is the better approach for the
> following reason.  I consider this an after-the-fact registration (RFC
> 5226 section 6.3) since this ASN seems to have widespread (mis-)use as
> many implementations strip it using their remove private ASN knobs and
> various networks undoubtedly have it deployed since it seems more than
> since a large amount of Internet documentation including RFC 1930 seem
> to include it as a private Use ASN.  Also, if this document progress,
> implementors will need to update their knobs and documentation anyway,
> so they, IETF and IANA can all be on the same page, allowing this ASN to
> be stripped if there are vendors that don't do it today (note even some
> vendors with published documentation stating that private ASN range is
> 64512-65534 strip 65535 with their remove private knobs).

A strong part of my recommendation has to do with the fact that this AS has
assumed a level of "magic" in some implementations.  In the case of much
older implementations on antique hardware may, in fact, be a magic internal
value as it is UINT16_MAX.  As a WG, we can deal with such things two ways:

1. Good grief, your code is that old and broken? Replace it/the hardware.
Let's use it!
2. We don't really need that one extra AS lying around.  Assume it may
potentially be toxic and try to pay no attention to the man behind the
curtains.

I will agree with anyone that the above opinion is one of strong cynicism.
:-)

> Can I suggest your alternative proposal for
> folks to comment on then is 4293918720 - 4294967295 (maintaining ~1M) or
> are you suggesting a different range location or sizing?

If you want ~1M, pick 2^20 addresses.  You could probably even just do 2^16
and have most providers happy.  (2^16 was the number I had in mind for my
draft.)  This lets you align the private AS number at a convenient as.dot
boundary.  I could even forsee someone's CLI saying PRIVATE.<num> :-)

-- Jeff