Hi Stephane, Thank you for sharing this information. This happens to be a topic that I have been considering for quite a while. I agree on most of the observations in this paper, e.g. "once you federate your protocol, it becomes very difficult to make changes. And right now, at the application level, things that stand still don't fare very well in a world where the ecosystem is moving." But I am also searching if there is different way to do federation in application world. Most of current federations at application level target specific applications, so many "semantics" in those applications are exposed to the peering/federating protocols/interfaces. Some people call it a " beads-on-a-string " architecture. It "naturally" results in the issue "hard to change". I am thinking if a "layered" architecture could be applied to the application world. The key point may be to define a function set, concise and sufficient for service innovations. The servers inside the federation implement these functions and turn a stable layer. The main goal is that to deploy new services, only the client software at the two ends need to be upgraded. No doubt that it is very challenging since unlike the connectivity, the services above connectivity are so various, it is questionable if it is feasible to define a stable layer conveying future service innovations. But I have an initial feeling that such a function set could probably be defined based on experience from file and database systems. But this idea is still at quite early stage... Jeffrey -----邮件原件----- 发件人: ietf [mailto:ietf-bounces@xxxxxxxx] 代表 Stephane Bortzmeyer 发送时间: 2016年5月11日 20:56 收件人: ietf@xxxxxxxx 主题: The ecosystem is moving A very interesting paper (I said "intesresting", I didn't say I agree!) on open networks where independant nodes with independently developed programs interoperate thanks to standards. The author claims closed and centralized systemes are better, because they allow faster evolution (he uses security as an example). Many IETF cases mentioned (XMPP, IPv6, email...) https://whispersystems.org/blog/the-ecosystem-is-moving/