#2412 BLOC Update.: Buddies not disappearing even when connection does

[Zarro Boogs per Child]

#2412: Buddies not disappearing even when connection does
-------------------------------+--------------------------------------------
  Reporter:  Zack              |       Owner:  morgs                          
      Type:  defect            |      Status:  closed                         
  Priority:  blocker           |   Milestone:  Update.1                       
 Component:  presence-service  |     Version:                                 
Resolution:  fixed             |    Keywords:  collaboration Update.1? review+
  Verified:  0                 |  
-------------------------------+--------------------------------------------

Comment(by daf):

 The current situation is as follows. Loudmouth has a facility for sending
 keepalives that operates by periodically sending a single space to the
 server. Gabble configures Loudmouth to send this keepalive every 30
 seconds that we're idle.

 The rationale for this approach was:

  - Presence is time-sensitive, so detecting network failure is important.
 In
    practice, this doesn't really work very well with the whitespace
    approach, because the TCP timeout is generally 2 hours anyway. Using
 TCP
    keepalives supports detecting disconnections better.

  - Gabble is sometimes used behind NATs with aggressive timeout policies.
    Periodically sending data keeps the connection mapping alive.

 Note that a failure on the local link is not the same as a failure in the
 connection to the Jabber server. If the Jabber server falls over, it will
 still be possible for packets to get to it, but we'll never get any
 replies.

 Adding a 'keepalive' parameter to Gabble could be a good compromise.

 I don't think we should worry too much about this right now; if we are
 concerned about Gabble's bandwidth usage then there are much worse
 offenders to go after.

-- 
Ticket URL: <http://dev.laptop.org/ticket/2412#comment:37>
One Laptop Per Child <http://dev.laptop.org>
OLPC bug tracking system