[jira] [Commented] (VYSPER-292) Detecting unexpected network disconnects

["Bernd Fondermann (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/VYSPER-292?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13084992#comment-13084992 ] 

Bernd Fondermann commented on VYSPER-292:
-----------------------------------------

As I said in my comment VYSPER-286#29/Jun/11 07:33, TCP/IP is unable to detect this kind of disconnect _as_long_as_ there is no data sent over the wire - neither side of the connection will detect it.
On the other hand, in the basic XMPP protocol, the server doesn't ping its clients, for good reasons.

Still, a solution would be to implement a server-to-client ping, but be aware of the fact that clients not under your control might not support it, it generates a lot more traffic and for flakey network connections this might cause unceccessary reconnects. Ping support is already present in the Vysper codebase, but servers do not ping clients regularily (and I certainly don't want to support it by default). See also http://xmpp.org/extensions/xep-0199.html

As a side note, please let us discuss these kind of topics on the dev list first and create new JIRA issues second. Thank you.


> Detecting unexpected network disconnects
> ----------------------------------------
>
>                 Key: VYSPER-292
>                 URL: https://issues.apache.org/jira/browse/VYSPER-292
>             Project: VYSPER
>          Issue Type: Bug
>          Components: connection handshake
>            Reporter: Arun Prem
>
> This is similar to the one mentioned in the issue 286. Since there are no ways found to reopen the issue (which was already marked as 'Resolved'), I'm creating a new issue.
> As a solution for the issue reported in 286, it is suggested to add a shutdown hook. But it seems it won't address the cases of unexpected network disconnects as given in the following scenario.
> 1. User1 logs in. The status is set as 'Available' by default.
> ==> User1's status is reflected in the messenger window of other logged in users.
> 2. Disconnect User1's workstation from the network.
> ==> Other user's list disappears from User1 messenger window.
> 3. Check the status of User1 from the messenger window of other logged in users.
> ==> User1's status still remains in the same for all other users.
> Expected: User1's status should be made offline to other users as soon as the network disconnects.
> The questions is how to detect the unexpected network disconnects for User1 and broadcast the status (as offline) to other logged-in users.
> Thanks... 

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