TODO

To be done :
    The address of the client is declared while it should only be the address
    of the server 

    Upgrade the logging function in order to be able to log message like
    "Refreshing peers DB ... done", or add log messages to specify that an
    action advertised by a previous log message has been completed

    use the server as a bootstrap node -> switch peer discovery to be done
    by vifibnet directly ?

    Use an algorithm to choose which connections to keep and/or establish
    instead of pure randomness
        |-> number of routes / tunnel 
        |-> favorise most used roads ?

    Replace comments at the beginning of functions with docstrings & give all
    fn docstrings

    Use a timeout for the server peersDB so we can flag unreachable peers and
    remove the peers whose certificate is no longer valid

    Handle LAN internally in order not to have catastrophic results ....
    ( avahi could be used )

To be discussed:
    U : Babel seems to be very long to establish the routes : maybe we should
        tell him thant we are not on a wired network but on a mobile network ?
    G : babel establish routes quickly enough i'd say. There are two new
        options : hello and wireless, for hello_interval and treating all
        interfaces as wireless. However, treating an interface as wireless
        doesn't lessen the hello_interval, it only changes how babel estimates
        quality link, and cost.
    U : from babel web page : "When the Babel daemon detects a wired network,
        it will use a larger interval between hellos".
        Moreover, it seems that the wireless option only means
        "hostile environment" which seems best for a resilient network.
        30 sec of hello interval seams also too much. The default value for
        babel is 4 sec (from babel man page).
        According to raphael's stats on the nexedi's server downtime,
        45% of the problems dont last more than 2 minutes, 55% no more than
        3 minutes If it takes 2 min to detect a dead connection, then we wont be
        solving many problems with our overlay network
    G : ok, so babel hello-interval should be set to a lower value,
        we should do some tests to pinpoint the best compromise between
        speed and bandwith usage.
        Btw, is there a doc ( pdf, image, file ) resuming Raphael's stats
        on nexedi's server downtime ? it could be useful for the internship
        rapport
==>     It takes babel between 3 times and 4 times the hello interval to
        reestablish connection, if a direct link is cut
    U : So we have to reduce the hello interval. 2min to detect a dead link is
        far too much.