After a week of fiddling, I think the PacketShaper is under control again. I’ve been living on the student net and making things reasonably responsive over here, and I believe not to the detriment of the college-owned net.
First, I believe that every fall we should run the shaper in discovery mode to pick up the new applications people are running. This should be done with the latest PacketWise release and classification plugins. That seemed to help a lot last week, picking up a number of new games and P2P apps.
Second, understand how to effectively put policies on different traffic patterns, recognizing the difference between requests and responses. It is better to put a middle to high priority policy on HTTP request traffic and then put a sliding rate policy of middle to high priority on the HTTP response. THe request is small and doesn’t care about per-flow bandwidth limits while the response can be much larger and can effectively be shaped on a per-flow basis. Interactive stuff, including POP3 and IMAP need to have pretty high priority, but again we can differentiate between those services hosted here and used from off campus versus those hosted elsewhere and used from on campus (the latter not getting as high priority). Background stuff, like SMTP, can be given a fairly low priority policy, but shouldn’t be shaped any other way.
Today I also set up some scheduled jobs to run on the shaper. Weekday evenings I increase web browsing and gaming bandwidth a bit, and then decrease them again weekday mornings. This means that at night and over the weekends some of the student-initiated traffic ought to see a better response than with static rules.
I think I’ll continue hanging out here on the student net for a little while, but at this point things seem to be working fairly well.
Posted by Rowan Littell at September 20, 2005 01:49 PM