Well, the most specific prefix wins in the forwarding selection process, but I won't make any comments on "best current practice" since "best" is somewhat relative to the idea of max-aggregation ....but this reference might help: G. Huston Request for Comments: 3221 Commentary on Inter-Domain Routing in the Internet ftp://ftp.rfc-editor.org/in-notes/rfc3221.txt [snip] 5.4 Lack of Common Operational Practices There is considerable evidence of a lack of uniformity of operational practices within the inter-domain routing space. This includes the use and setting of prefix filters, the use and setting of route damping parameters and level of verification undertaken on BGP advertisements by both the advertiser and the recipient. There is some extent of 'noise' in the routing table where advertisements appear to be propagated well beyond their intended domain of applicability, and also where withdrawals and advertisements are not being adequately damped close to the origin of the route flap. This diversity of operating practices also extends to policies of accepting advertisements that are more specific advertisements of existing provider blocks. [snip] - ferg -- Ashe Canvar <acanvar@gmail.com> wrote: Hello all, BGP design question. My scenario is very much like an online gaming company with servers on multiple continents. Details : 1. I have datacenters/servers in many POPs globally. 2. I am a stub AS with multiple ISPs available at each POP. 3. I do not have the resources to buy dedicated fiber to link these POPs, so my backbone is essentially a bunch of VPN tunnels. 4. I own a /21. Of which I announce /24's. 5. I have a mechanism to allocate client sessions to any ONE of the POPs based on network performance (which is what I want to optimize). Questions : I presently announce different /24's out of different POPs to localize traffic. All these prefixes are announced from the same AS number. This obviously can't be best practice. Are there any published BCPs or RFCs tackling this issue ? Is it recommened that I get multiple AS numbers and announce symmetrically from each "smaller" AS ? Or should I announce inconsistently from different locations ? Thanks! -- "Fergie", a.k.a. Paul Ferguson Engineering Architecture for the Internet fergdawg@netzero.net or fergdawg@sbcglobal.net