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<DIV><SPAN class=939235611-27112006><FONT face=Arial size=2>AG3 has has
made it simpler for us manage our rooms at CCLRC (both RAL & Daresbury);
most notably with the ability to 'lock' a system into using Unicast.
I openly, the following is based on my perception of how AG3 works; and may
not be entirely correct.</FONT></SPAN></DIV>
<DIV><SPAN class=939235611-27112006><FONT face=Arial
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=939235611-27112006><FONT face=Arial size=2>Last week, it became
apparent that the MO for the way AG3 selects a bridge was working against
us.</FONT></SPAN></DIV>
<DIV><SPAN class=939235611-27112006><FONT face=Arial size=2>It would appear that
now anyone can create a bridge which AG3 will find and select dependent on the
time it takes to ping. </FONT></SPAN></DIV>
<DIV><SPAN class=939235611-27112006><FONT face=Arial size=2>This may not however
be the best selection method for a site.</FONT></SPAN></DIV>
<DIV><SPAN class=939235611-27112006><FONT face=Arial
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=939235611-27112006><FONT face=Arial size=2>Like probably many
other sites, we have strict firewall rules & guidelines to which we must
adhere, and changes require time to be processed by 'other departments. We have
therefore selected 5 'known' bridges around the globe that we expect to use
regularly, or as fallbacks, and only these pass through unhindered. AG3 selects
the 'closest' bridge it finds to route through currently.</FONT></SPAN></DIV>
<DIV><SPAN class=939235611-27112006><FONT face=Arial
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=939235611-27112006><FONT face=Arial size=2>Last week on at
least one occasion, the bridge list could not be seen from our sites, so there
was no bridge at all available to our AG3 systems and we had to revert back to
AG2.4 until later in the day.</FONT></SPAN></DIV>
<DIV><SPAN class=939235611-27112006><FONT face=Arial
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=939235611-27112006><FONT face=Arial size=2>I would like to
suggest an enhancement to the current system (if Unicast is selected), where the
client operation would:</FONT></SPAN></DIV>
<DIV><SPAN class=939235611-27112006><FONT face=Arial
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=939235611-27112006><FONT face=Arial size=2>1. Check for bridges
against a saved list, and either works from the new list (if available) or the
saved one.</FONT></SPAN></DIV>
<DIV><SPAN class=939235611-27112006><FONT face=Arial size=2>2. Compares the
'current' list to a list (perhaps tagged in preferences?) of preferred
bridges, and tries to connect to the #1 preferred location.</FONT></SPAN></DIV>
<DIV><SPAN class=939235611-27112006><FONT face=Arial size=2>3. If preference #1
fails or is not on the new list, then #2 is selected (and so on in a cascade
fashion)</FONT></SPAN></DIV>
<DIV><SPAN class=939235611-27112006><FONT face=Arial size=2>4. Perhaps this
concept could also be adopted in the event of a heartbeat failure' from the
bridge, so the client would automatically drop down to the next bridge, instead
of just flagging up a failure.</FONT></SPAN></DIV>
<DIV><SPAN class=939235611-27112006><FONT face=Arial
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=939235611-27112006><FONT face=Arial size=2>I know the purists
will say that Unicast is a fallback to Multicast, but to some sites like ours it
is our mainstay, and will continue to be for the foreseeable future. To us, the
most important thing is for the meeting to take place with minimum of fuss &
interruption; in some cases self operated by 'less knowledgeable people. I feel
this would make the system simpler to manage & operate.</FONT></SPAN></DIV>
<DIV><SPAN class=939235611-27112006><FONT face=Arial
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=939235611-27112006><FONT face=Arial size=2>Does this make
sense? Would it be difficult to implement? Can anyone else see
flaws?</FONT></SPAN></DIV>
<DIV><SPAN class=939235611-27112006><FONT face=Arial
size=2></FONT></SPAN> </DIV>
<DIV><FONT face=Arial size=2><SPAN
class=939235611-27112006>Regards,</SPAN></FONT></DIV>
<DIV align=left><FONT face=Arial size=2>Paul Bonnett</FONT></DIV>
<DIV align=left><FONT face=Arial size=2>Access Grid Videoconference Support
& Development<BR>Rutherford Appleton Laboratories<BR>e-Science Centre<BR>R1
Room 2.21</FONT></DIV>
<DIV><FONT face=Arial size=2>Chilton, Didcot,</FONT></DIV>
<DIV><FONT face=Arial size=2>Oxfordshire, OX11 0QX</FONT></DIV>
<DIV><FONT face=Arial size=2> </DIV>
<DIV align=left>Tel: 01235 778329<BR> <BR><A
href="mailto:P.Bonnett@rl.ac.uk">P.Bonnett@rl.ac.uk</A></FONT></DIV>
<DIV align=left><FONT face=Arial size=2></FONT> </DIV>
<DIV align=left><FONT face=Arial size=2><A
href="http://www.e-science.clrc.ac.uk/web/projects/accessgrid">http://www.e-science.clrc.ac.uk/web/projects/accessgrid</A><A
href="http://hpcsg.esc.rl.ac.uk/"></A></FONT></DIV>
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