Hi all. I have written a patch for "Avahi", that solves the bugs [UPSTREAM] <a href="http://bugs.sugarlabs.org/ticket/3748">http://bugs.sugarlabs.org/ticket/3748</a> [DOWNSTREAM] <a href="http://dev.laptop.org.au/issues/1332">http://dev.laptop.org.au/issues/1332</a> ########################################################################################################### For brevity, I am specifying the use-case :: <pre style="font-family:arial,helvetica,sans-serif"> a) XO-1 connects to telepathy-salut. b) XO-2 connects to telepathy-salut. Both XO-1,and XO-2, are able to see each other in the neighborhood-view. c) XO-1 disconnects. XO-2 is now no more seen in XO-1's neighborhhod-view, BUT XO-1 IS CONTINUED TO BE SEEN IN XO-2'S NEIGHBORHOOD-VIEW. The expected behaviour is that XO-1 should also disappear from XO-2's neighborhood-view after some time. ########################################################################################################### The upstream bug id is :: <a href="https://bugs.freedesktop.org/process_bug.cgi">https://bugs.freedesktop.org/process_bug.cgi</a> ########################################################################################################### The patch is located at :: <a href="http://people.sugarlabs.org/ajay/root/freedesktop_bug_51501/common-patch-for-f14-and-f17/customize-avahi-default-ttl-values.patch">http://people.sugarlabs.org/ajay/root/freedesktop_bug_51501/common-patch-for-f14-and-f17/customize-avahi-default-ttl-values.patch</a> For brevity, I am pasting the patch description Please refer <a href="https://bugs.freedesktop.org/show_bug.cgi?id=51501">https://bugs.freedesktop.org/show_bug.cgi?id=51501</a> History :: =========== As pointed out by Simon McVittie in <a href="https://bugs.freedesktop.org/show_bug.cgi?id=51501#c4">https://bugs.freedesktop.org/show_bug.cgi?id=51501#c4</a>, <a href="https://tools.ietf.org/html/draft-cheshire-dnsext-multicastdns-15#section-10">https://tools.ietf.org/html/draft-cheshire-dnsext-multicastdns-15#section-10</a> suggests that the Time-To-Live (TT) of the mDNS record is likely to be 120 seconds. However, for all purposes, in whatever testing I came across Avahi, the TTL in effect was 75 minutes , which seemed a bit too late a notification of buddy-going-disconnected. Fix :: ====== Decrease the Time-To-Live (TTL). Solution :: =========== Obviously, the easiest solution is to set the appropriate values in #define AVAHI_DEFAULT_TTL_HOST_NAME #define AVAHI_DEFAULT_TTL However, this has the following caveats :: (i) It needs a re-compilation/re-packaging of avahi rpms, for every change in the values. This is a major deployment headache. (ii) Also, there is no ideal "TTL" values. The lesses the TTL values, more frequent multicast DNS packets will be exchanged between a pair of peers, thus leading to more traffic. However, too large a TTL value, would mean that the peer gets too late a notification of the buddy going disconnected. Thus, ideal values can only be found out by testing in real-field. This requires easy configuration of the TTL values, without needing to re-compile the rpms. Solution-Implementation :: ========================== The cutomized TTL values will be read during "avahi-daemon" startup. 1. AVAHI_DEFAULT_TTL_HOST_NAME will be set to the value, contained in the file "/etc/avahi/avahi-default-ttl-host-name.conf". Default value is the same as before, i.e. 120 (seconds). 2. AVAHI_DEFAULT_TTL will be set to the value, contained in the file "/etc/avahi/avahi-default-ttl.conf". Default value is the same as before, i.e. 4500 (seconds), which is equal to 75 minutes. How to customize :: =================== a) "sudo service avahi-daemon stop" b) Change the values in the corresponding conf files. c) "sudo service avahi-daemon start" AUTHOR: Ajay Garg <<a href="mailto:ajay@activitycentral.com">ajay@activitycentral.com</a>> Thanks to :: Will Thompson <<a href="mailto:will.thompson@collabora.co.uk">will.thompson@collabora.co.uk</a>> Simon McVittie <<a href="mailto:simon.mcvittie@collabora.co.uk">simon.mcvittie@collabora.co.uk</a>> Xavier Claessens <<a href="mailto:xclaesse@gmail.com">xclaesse@gmail.com</a>> ########################################################################################################### The pre-compiled RPMS (patched), both for F14 and F17, are available at :: <a href="http://people.sugarlabs.org/ajay/root/freedesktop_bug_51501/platforms/f14/RPMS/">http://people.sugarlabs.org/ajay/root/freedesktop_bug_51501/platforms/f14/RPMS/</a> <a href="http://people.sugarlabs.org/ajay/root/freedesktop_bug_51501/platforms/f17/RPMS/">http://people.sugarlabs.org/ajay/root/freedesktop_bug_51501/platforms/f17/RPMS/</a> ########################################################################################################### I have done the preliminary testings, and things seem to work as expected. In particular, now the XO-2 disapplears from XO-1's neighborhood view, after the number of seconds specified in the file "/etc/avahi/avahi-default-ttl.conf". ########################################################################################################### Kindly test and review the patch, as this solves a pretty important issue :) Thanks and Regards, Ajay </pre>