The providers I'm aware that perform filtering of this sort normally do so based on the length of allocations from the RIRs (ARIN, APNIC & RIPE) within the associated address blocks. These polices have little to do with the RADB (Routing Arbiter Database) or other IRRs. Of course, if inter-provider filtering were feasible the specific route objects would be obtained from the RIRs and pretty much any correctly registered route (of a "more reasonable than today" length) would probably be accepted by those providers. Consulting the allocation guidelines for those specific RIRs should help answer your question. Consulting the "ISP Resources" section of the NANOG web server should provide useful information regarding specific filtering policies implemented by a few ISPs. -danny

Can anyone point me to a centralized resource for Tier 1 and Tier2 providers' accept policies? I have found that when some of my circuits go down various parts of the 'Net become unreachable and I attributed that to the size of that announcement being a /24. I assume that the carriers I'm having issue with are not using RADB as I registered all of my netblocks,