[squid-users] prefer_direct configuration

I am trying to setup a new proxy server at a remote location which has both a T1 link to our main office and a DSL connection to the internet.  The DSL connection has a much larger download than the T1 so it's preferable to use it for web browsing, but I would like to be able to have the proxy server automatically route traffic through the T1 and use our proxy servers here as parents in the event that the DSL would fail and the T1 line is still up.

I have added the proxy servers at our main office using the cache peer entries, and defined the icp_port.

cache_peer 10.50.20.5 parent 8080 8181
cache_peer 10.50.20.4 parent 8080 8181
icp_port 8181

Then added the prefer_direct on entry.
prefer_direct on

I tested by manually entering a false route on the remote proxy server for one website, it does load, but only after waiting for a timeout  for each and every request (watching packet traces appears to show 4 attempts for each before falling back to the parent cache).  Since this covers not only the html files, but requests for each image, and any subsequent links form the same web site all continue to follow this behavior.  The end result is for a small page with a few images it takes anywhere from 2 to 4 minutes to complete.
Is there a way to adjust the timeouts, and perhaps have it cache the path for a period of time after having one failure before trying again?
Or is my method of testing flawed, and causing this behavior?
 
Thanks,
     Dean Weimer
     Network Administrator
     Orscheln Management Co
Received on Tue Jul 08 2008 - 17:59:05 MDT