title: Difference between Push notification and pubsub in XMPP
body: <p>What is the difference between pubSub(XEP-60) and push notifications(XEP-357) in XMPP in terms of the use-cases which they can or cannot support.
  From what I understand, in PubSub, the nodes(lets say the clients) can subscribe to a topic, and the publisher(lets say the XMPP server) and send messages to all the clients which have subscribed.</p>
  
  <p>Isn't this functionally similar to push notifications?
  What is it that can be achieved using push notifications which can't be done using pubsub and vice-versa.</p>