At some point, there started to be a business case for large providers to interconnect with bilateral private links as well as at exchanges. When did such links first get used for commercial traffic? In the beginning, were they short-haul connections between cages in exchanges, or WAN links between major provider hubs? I'm referring here only to interprovider links, not to transit customers.
Mark Borchers added,
Well, if this is to be a comprehensive list, private interconnects predated the commercial Internet. At OARnet in Ohio, we set up peering with CICNet in a facility near the Ohio Supercomputer Center in order to avoid long round trips.
Clearly, there's a need to broaden my scope! I do want differentiate between good solid technical examples, such as yours for OARnet-CICNet, between examples where the suits had an economic motivation. The latter, I would assume, came later. While I recognize I won't be able to publish the details of many NDA-covered commercial private peerings, it is my hope to identify when this practice began. A side motivation for this particular point is to identify when commercial NDA considerations might have restricted the potential ability of routing registries to give reasonably accurate representations of topology and policy. Yeah, yeah...if everyone DID put all their policies in an RR. Yet Another Issue.