On Mon, Oct 24, 2016 at 10:42 PM, Stephen Dubovsky <smdubov...@gmail.com> wrote: > Why would UDP need resends on a shared ethernet port? There are no > collisions on a full-duplex port & switch (which is pretty much ALL of them > now-a-days.) Passive hubs went the way of the dodo.
Of course, but you are assuming an ideal active switch, and that may or may not be the case. All the switched ports are sitting on an internal bus, whose bandwidth has to be better than N/2*individual port bandwidth, because in principle, all port pairs could be active at the same time; on a cheap switch that 'bisection' bandwidth may not quite be there. Also, in general, two originators could be trying to talk to the same receiving port and collide on it---switches of course must implement some form of 'store and forward' to be able to decide where to switch the packet to, but cheap switches do not have a deep store queue---maybe they can handle one or two packets but not more than that. So, in practice, the collisions and dropped packets are possible. ------------------------------------------------------------------------------ The Command Line: Reinvented for Modern Developers Did the resurgence of CLI tooling catch you by surprise? Reconnect with the command line and become more productive. Learn the new .NET and ASP.NET CLI. Get your free copy! http://sdm.link/telerik _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
