Re: [Condor-users] Using STUN instead of the CCB

[Todd Tannenbaum <tannenba@xxxxxxxxxxx>]

> > I've been reading about the Condor Connection Broker (CCB) and my
> > understanding is that it provides a central point where two services,
> > like the scheduler and the starter for example, can exchange packets
> > if they are both behind firewalls. So, I was wondering if Condor also
> > considered using STUN [1] to achieve the same objective while having
> > the above mentionned "central point" incur significantly less bandwidth
> > overhead. 

Indeed, we initially looked at leveraging STUN, but our hopes were 
dashed when we ran some initial experiments to see how well STUN 
techniques work "out in the real world".  Using a couple dozen sits on 
the Open Science Grid, we found that only a handful of the sites that 
allowed outgoing TCP connections also allowed STUN to operate (for 
various reasons).  While STUN may be useful when using the default 
settings of a typical (semi)-stateful linksys home router box, it seemed 
to fall flat for traversing across institutional firewall configs 
prevalent at universities and government labs - i.e. the sort of 
boundaries we wanted Condor to traverse.

For what it is worth, I was disappointed by these results, as I had 
pinned my hopes on STUN.  Sniff.

--
Todd Tannenbaum                       University of Wisconsin-Madison
Condor Project Research               Department of Computer Sciences
tannenba@xxxxxxxxxxx                  1210 W. Dayton St. Rm #4257
Phone: (608) 263-7132                 Madison, WI 53706-1685