File

---
labels:
- 'Stage-Beta'
summary: 'XEP-0198: Reliability and fast reconnects for XMPP'
...

Introduction
============

By default XMPP is as reliable as your network is. Unfortunately in some
cases that is not very reliable - in some network conditions disconnects
can be frequent and message loss can occur.

To overcome this, XMPP has an optional extension (XEP-0198: Stream
Management) which, when supported by both the client and server, can
allow a client to resume a disconnected session, and prevent message
loss.

Details
=======

When using XEP-0198 both the client and the server keep a queue of the
most recently sent stanzas - this is cleared when the other end
acknowledges they have received the stanzas. If the client disconnects,
instead of marking the user offline the server pretends the client is
still online for a short (configurable) period of time. If the client
reconnects within this period, any stanzas in the queue that the client
did not receive are re-sent.

If the client fails to reconnect before the timeout then it is marked
offline as normal, and any stanzas in the queue are returned to the
sender as a "recipient-unavailable" error.

Configuration
=============

  Option                      Default           Description
  --------------------------- ----------------- -----------------------------------------------------------------------------------------
  smacks\_hibernation\_time   300 (5 minutes)   The number of seconds a disconnected session should stay alive for (to allow reconnect)

Compatibility
=============

  ----- -----------------------------------
  0.9   Works
  0.8   Works, use version [7693724881b3]
  ----- -----------------------------------


Clients
=======

Clients that support XEP-0198:

-   Gajim
-   Swift (but not resumption, as of version 2.0 and alphas of 3.0)
-   Psi (in an unreleased branch)
-   Yaxim

[7693724881b3]: //hg.prosody.im/prosody-modules/raw-file/7693724881b3/mod_smacks/mod_smacks.lua