The issue of reverse DNS is the only reason for having "unique" exchange point addressing. The fact as I see it is that the exchange point is not a destination. The exchange point addresses are used solely as a transit "space", and it's nice to know what you're hopping accross. The only time that the exchange point as routable space has been and issue for me is when reachability to those network blocks is being readvertized by a peer. There is NO reason that a service provider needs to readvertise an exchange point network block. It's not a destination. Eliminating this specific abuse would be a Good Thing(tm). Since there is no technical reason for an exchange point to be routable, it comes down to whim. I *like* having unique exchange point addresses for troubleshooting purposes, for all the reasons below. That does not mean it's not perfectly reasonable for an exchange point operator to make it non-routable addressing, since it's their exchange point. If it weren't for the RA's, the ATM environment has no need to be a shared network anyway. Might as well make the VC's individually numbered /30's, or 10.254.254.0/24. Why not? Curt- ------------------------------ On Sun, Jan 24, 1999 at 09:35:13PM -0800, Randy Bush wrote:

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o does anyone see why the exchange address space needs to be globally routable? Traceroute.

as the fabric is used for peering under bi-lats, if we each announce the mesh to our customers and not to our peers, then i believe you will have your tracroutes and yet the prefix does not have to be globally routable, e.g. could be 209.666.42/24.

randy

Holdon, i don't even see the need for that; if you traceroute out, the packets will cross the exchange irregardless of whether you're announcing it to your customers, and a message of TTL exceeded will be generated from the exchange's address.. The important question is, should they be globally UNIQUE for troubleshooting purposes? I think so. Mike ------------------------------