> > no. what an ISP advertises to itself and what it advertises > > (and accepts) across ISP boundaries are different things. > > You assume that an ISP is not paid enough to make sure the upstream is > also paid to accept it.
If an ISP wants to pay each of its upstream ISPs to advertise those routes, and provide a single bill to its customers, it's free to do so. As routing table space becomes more precious, so will each ISP's cost to advertise a prefix. Provider-based routing will be cheaper because it needs to advertise fewer prefixes due to aggregation. > > there are even better business reasons for filtering such > > advertisements unless the owner of that block of addresses is paying you > > specifically to route them within your network. that, and the threat of > > router overload for ISPs that don't filter such > > advertisements, should be sufficient. > > We have an existence proof in the current BGP table that it is not > sufficient. as I already said, I don't think the current situation is a good predictor because of the IPv4 swamp, and because there is no clear distinction between provider-based and provider-independent addresses in IPv4. Keith -------------------------------------------------------------------- IETF IPng Working Group Mailing List IPng Home Page: http://playground.sun.com/ipng FTP archive: ftp://playground.sun.com/pub/ipng Direct all administrative requests to [EMAIL PROTECTED] --------------------------------------------------------------------
