man, zeromq is some neat stuff truth http://i.imgur.com/haspR.jpg wow up_the_irons: we're looking at replacing xmpp with zeromq on v 3.0 of our appstack. up_the_irons: what are you using it for? rabbitmq is also hawt jpalmer: I'm guessing you're not using XMPP for simply chatting then? (Not that you couldn't build an IM service with a 0MQ transport...) we're doing a LOT with xmpp, that it wasn't really designed for, or good at. heh I've used xmpp for intra-server message passing in the past (5+ years ago). it did well enough. Was relatively small scale though and I would definitely jump on 0MQ now. I will say that XMPP is nothing if not extensible though we're using it in hospitals. for messaging, voip session setup, delivering critical alarms to nurses.. etc. oh, and we're doing it over (usually) poor quality wifi.. so there are lots of drops/disconnects. at least xmpp retransmits upon reconnect! well, not well in our scenario. if the phone is unavailable, we send it as an apple push, and need to remove it from the queue does xmpp support "guaranteed" delivery? not sure if that's the right word to describe it... basically, retry until it gets through jlgaddis: I'm not sure, but I know it supports delivery receipt, so I'm sure there must be some implementation/addon/etc that would retry . (As far as I know, most setups will store and and pass it along) yeah, delivery receipt is basically what i meant... i was thinking it does, but it's been a few years since i used jabber (previous job) its supposed to, but some im apps screw it up I think, don't rely on blackberry gtalk client, it shows online at google and online at blackberry at times, yet manually disconnecting and reconnecting is the only way to get it to start receving messages sent from elsewhere or have others receive messages sent heh, that could (in theory) be fixed at the server side If the server would reach out, ping, etc Not guaranteed but an option when running a jabber server, I'd notice I could send a message to an offline contact, disconnect my client, connect to the offline account, and receive the message. I was impressed. lol that reminds me, toddf, and i now remember the answer to my own question Anyhow, the client must ack every message received from the server. Hence, the server will know whether it was delivered, and will report it as such back to the sender. i remember similar things happening when we had a jabber server (receiving messages from when i was offline)