> > E2e places the cost of interoperability on the ends, where it belongs. > > The basic principle (it's NOT an argument) is that functions should go where > they most efficiently belong. Yes. I think that's a fine restatement in terms of architectural optimisation. Personally I prefer to think about this in terms of costs, because it's all too easy to conflate "efficient" with "cost effective". There is often a correlation, but not always, and of course it is the latter that actually drives procurement and so deployment. (The actor bearing the cost isn't necessarily the one performing the architectural function. I pay my ISP to run BGP; in principal I could make alternative arrangements myself that could yield greater efficiency, but it would be wildly less cost effective). A corollary to this is that designing successfully for systemic efficiency is really hard if you don't understand how the costs will be bourn throughout the system. Josh. Jisc is a registered charity (number 1149740) and a company limited by guarantee which is registered in England under Company No. 5747339, VAT No. GB 197 0632 86. Jisc’s registered office is: One Castlepark, Tower Hill, Bristol, BS2 0JA. T 0203 697 5800. Jisc Services Limited is a wholly owned Jisc subsidiary and a company limited by guarantee which is registered in England under company number 2881024, VAT number GB 197 0632 86. The registered office is: One Castle Park, Tower Hill, Bristol BS2 0JA. T 0203 697 5800.