On Mon, Oct 08, 2007 at 05:43:03PM -0400, Keegan.Holley@sungard.com wrote:
I have a client that wants us to advertise an IP block assigned by another ISP. I know that the best practice is to have them request an AS number from ARIN and peer with us, etc. However, I cannot find any information that states as law. Does anyone know of a document or RFC that states this?
If the address space is assigned to another provider, getting clarification from them directly or indirectly(*) that the customer is allowed to use it, if it is portable or allowed to be seen outside their ASN, etc. If their are truly attempting to multihome, doing so with multiple-origin ASNs can create nondeterministic behavior in the exact failure conditions that multihoming is seeking to solve. Given the clue level of the customer or their business/traffic, it may not matter (anycasters, CDNs, or other edges with levels of indirection). Most ISPs quite simply have a policy that multihoming is done by BGP in such and such fasion and that's that. Cheers, Joe (*) whois delegation at best, some providers indicate portability or multihoming policy in whois or IRR allocations,etc -- RSUC / GweepNet / Spunk / FnB / Usenix / SAGE