Hi Henry et al, There's no real problem with your current space. Assume for the minute that each of your offices has a UU T1. You announce the chunks of your /22 through your various T1s, and that announcement (along with the UU/14) is passed along to UU customers and peers. Verio will ignore the /22, but will direct traffic to UU because they will accept the /14. so no problem there. The only possible issue is this: assume one T1 to UU and one to <non-Verio provider>. UU T1 goes down, therefore /22 withdrawn there, /22 announcement through <provider> becomes only route. Verio ignores this, and directs traffic to UU (via the /14), and UU will then direct traffic to <provider> because UU has very liberal routing policies. So in the worst case, you could get some sub-optimal routing, but nothing particularly bad, and Verio is the only substantive ISP who still uses these filters (AFAIK). The bigger issue in that case would be getting the UU line up faster :) -David Barak "Quis custodes ipsos custodiet?" - Juvenal Henry Yen wrote: We were recently assigned a /22 from UUNet in conjunction with some transit we're buying from them. The space is inside their superblock, 65.242.0.0/14. We are concerned that our route announcement of this block would be filtered out by some other providers, as it's not class C/swamp space (or even class B space for that matter). Verio's current policy, for one, indicates that this would be so. This is of particular concern to us as our little network encompasses several physical partially-meshed locations, with a mix of varying bandwidths both upstream as well as intra-location. Traffic Engineering is what we think is a reasonable (business) approach to address our flexibility needs, and so we're trying to move to address space(s) that would be least likely to be BGP filtered. We've asked for a different block from UUNet but the request didn't meet with success; UUNet suggested that any problems encountered as a result of this allocation could probably solved by e-mailing any NSP whose traffic interchange with us might be negatively affected (unlikely, to be sure, but still...), and would then change their filter (I'm unconvinced of this scenario). I briefly browsed the NANOG archives, and didn't see this issue discussed recently. Have the BGP filtering policies for "most" ISP/NSP's been relaxed to the level of "accept /24's from class A (ARIN-allocated) space"? Am I mis-reading Verio's posted policy? Is there anyone from UUNet who might choose to comment? Is there something else I'm misunderstanding? __________________________________________________ Do You Yahoo!? Yahoo! Tax Center - online filing with TurboTax http://taxes.yahoo.com/