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North American Network Operators Group Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical Re: Why does Sprint have address filters again?
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 ([email protected])| 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
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