> How do we define "important"? There's the challenge. :-) True. But not only "how", but also "where" it is defined. The received can define what it wants, the xmpp server can define what to forward under certain conditions, and the sender can define the priority of a message.
Many network protocols have solved this by letting the sender determine a priority or QoS level for each message. The sender normally knows if something is "important" (for instance an alarm, or a call or control command) or "normal" (informational message) or "less important" (recurrent status update), for instance, and so no complex logic for this is required. An objection could be made that an application could then choose to send all messages as "important" messages, overriding any throttling logic. But in practice, this would be counterproductive since users would quickly find out what service/device/address works badly and stop using it or unfriending misbehaving contacts. The above solution could then hypothetically be complemented by a simple subscription mechanism on the client, or an automatic rule on the xmpp server determining what messages to forward and when, and perhaps also with bandwidth limits on different types of messages, and if messages not being forwarded should be treated as offline messages or thrown away (based on message priority). Best regards, Peter Waher
