2.2 KiB
labels:
- 'Stage-Alpha' 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)
smacks_enabled_s2s false Enable Stream Management on server connections? Experimental
smacks_max_unacked_stanzas 0 How many stanzas to send before requesting acknowledgement
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)
- Conversations
- Yaxim