Hi Wendy, On Tue, Sep 06, 2016 at 03:37:45PM -0400, Wendy Roome wrote: > On 09/06/2016, 14:15, "Sebastian Kiesel" <[email protected]> wrote: > >On Mon, Sep 05, 2016 at 04:16:37PM -0400, Wendy Roome wrote: ... SSE ... > >> ***** Could this be made optional? As in, give me the diff for the .. > >>map > >> since tag ... > >> > >> Alas, that only works for maps with tags. Eg, that would work with > >>Network > >> Maps. But it would not work for Cost Maps, or Endpoint Cost requests, or > >> Endpoint Property requests, etc. > > > >Could we use this draft to introduce a tag to the cost map, for the > >purpose of requesting diffs? > > > >Then, the mechanism would work with Network Map and Cost Map. > >These two are probably the most important targets for periodic > >incremental updates. > > > Tagging cost maps might be a good idea, but there are some possible > problems, and I think that needs a separate draft. Do you want to do > submit one? Or formally solicit comments?
Do you see further use cases for such a tag? > >> ***** I am not really convinced that in every scenario sending a keep > >> alive message every 15 seconds is more efficient than the client asking > >> for updates in similar time intervals. > >> > >> Keep-alives are much more efficient, because they just send 10 more > >>bytes > >> on an existing TCP connection. Eg, one message. A request requires > >>setting > >> up a new TCP connection. That takes several messages, involved > >>allocating > >> new ports, etc. It is a lot more overhead on both the client and the > >> server. > > > >You are right, opening a new TCP connection every 15 seconds is less > >efficient than sending 10 bytes every 15 seconds over an existing > >connection, But there may be a break-even point ... What if I want the > >updates only every 120 seconds? Is one new TCP connection more > >effort than 8 keep-alives? Or 16? > > > >Maybe it is not worth the effort of changing the spec and adding some > >explanation is the better approach, but the current document leaves some > >feeling of strange asymmetry in me - one mechanism optional, the other > >one mandatory without a good explanation why. > > > >Sebastian > > > The keep-alive time is in the SSE specification: > > Legacy proxy servers are known to, in certain cases, drop HTTP connections > after a short timeout. To protect against such proxy servers, authors can > include a comment line (one starting with a ':' character) every 15 > seconds or so. yes, the 15 seconds is in the SSE spec. that means, if I need updates every X seconds, I will either recveive X/15sec keep-alives per update period (and get the updates as the server generates them), or I will have to establish one TCP connection per update period (and explicitly ask the server for updates). With growing X, there will be a break-even point where the second approach will become more efficient. The question is, if we are beyond that point, could there be cases where JSON merge patch still makes sense? Thanks Sebastian _______________________________________________ alto mailing list [email protected] https://www.ietf.org/mailman/listinfo/alto
