On Mon, Jun 01, 1998 at 12:36:19AM -0700, Patrick W. Gilmore wrote:
At 06:57 PM 5/31/98 -0500, Karl Denninger wrote:
Second Q: How many AS numbers are available in total?
Currently an ASN is a 16-bit number.
And a whole lot (~1/2) are reserved to IANA. Specifically:
32768-64511 IANA-RSVD 64512-65535 IANA-RSVD2
You can find this on ftp://rs.arin.net/netinfo/asn.txt (even if it hasn't been February ;).
The second block is the one you have to worry about since those numbers are used for things like BGP confederations. I believe the first block could be allocated to the general public, but you'd have to check with someone more cluefull to be sure.
Well, other than the definition of an ASN as a "short" in router software and BGP4, there's no *reason* an ASN has to be a short integer. That is, it wouldn't be difficult *at all* to define BGP4.1 in which an ASN was either defined as a "long" or as a "numeric string of arbitrary length". Its not like an ASN is in the header of an IP packet (where field lengths are limited) you know. I suspect the first "reserved" block is due to suspected buggy implementations that defined an ASN as a *signed* short. Obviously that's not an issue any longer, or the internal "reserved" numbers wouldn't work. -- -- Karl Denninger (karl@MCS.Net)| MCSNet - Serving Chicagoland and Wisconsin http://www.mcs.net/ | T1's from $600 monthly / All Lines K56Flex/DOV | NEW! Corporate ISDN Prices dropped by up to 50%! Voice: [+1 312 803-MCS1 x219]| EXCLUSIVE NEW FEATURE ON ALL PERSONAL ACCOUNTS Fax: [+1 312 803-4929] | *SPAMBLOCK* Technology now included at no cost