Andrew N. Shrosbree wrote: > What I find appealing is that when the user needs the image, they establish a > direct peer-to-peer connection that does not have to go through an > intermediary > gateway.
Sure, but the "alternative" model we have just been discussing involves direct P2P connections - no middleman, no tollbooth. That's the whole point. The only bits of centralised infrastructure which are required are a PKI and an associated directory service for Web services. and even both of these can be run in a distributed or federated fashion. Tim C > Tim Churches wrote: >> Andrew N. Shrosbree <[EMAIL PROTECTED]> wrote: >> >>> Gavan, >>> >>> Your question regarding whether it is appropriate to use a US-centric >>> radiology model is very pertinent. The IHE model is, IMO, excellent for >>> handling the kind of huge blocks of data inherent in the retrieval of >>> images. Having only a 'manifest' stored centrally makes the process >>> extremely efficient. >>> >> >> In what way does having a central "manifest" make the process extremely, or >> even more efficient? The actual (large) image files still need to be sent or >> retreived from provider to client (or v-v). The only difference is that in >> the IHE model the recipient polls the central "manifest" Web service to see >> if anything is waiting to be picked up by it, whereas in the direct Web >> service model which we have been discussing, the sender tries to send >> directly to the recipient and if the recicient is not contactable, teh >> sender tries again later and/or takes alternative action (eg if the >> information is urgent). >> >> As has been discussed, the overhead of resending iff (if and only if) a >> recipient Web service is offline is not likely to be any more than the >> overhead of everyone having to constantly poll a central "manifest" service >> or clearinghouse. Plus it avoids the very significant central point of >> failure which a "manifest" service represents. And as Gavin points out, the >> IHE model of a central manifest doesn't help when more complex interactions >> between Web services are involved, rather than just "Here's Mrs Blogg's >> chest xray". >> >> Tim C _______________________________________________ Gpcg_talk mailing list [email protected] http://ozdocit.org/cgi-bin/mailman/listinfo/gpcg_talk
