Re: Dynamic Internet Bandwidth Allocation

[Josh Richard <jrichar4 () D UMN EDU>]

On Wed, Feb 1, 2012 at 8:00 AM, Miller,James R <millerj () uakron edu> wrote:

> Without too much study so far, it appears that our Exinda traffic shaping
> appliance may be capable of achieving this with virtual circuits and
> scheduling. Is there anyone out there doing this currently, and if so would
> you mind sharing what equipment or software you are using to do this?


We are not using the Exinda product but have used other commercial products
in the past with mixed success. I see Jeff mentioning Procera, that was one
of the evaluated products.  +1 to that, the product looked very
interesting, had good reporting and for most installations could work well.

There is a good article on a different approach...
http://www.educause.edu/EDUCAUSE+Quarterly/EDUCAUSEQuarterlyMagazineVolum/DirectingTrafficManagingIntern/163105
which should be read while we check our stance on this issue.

For us, we rate limit our guest wireless network using a number of
GNU/Linux machines running surprisingly simple scripts written in tcng.  To
address the hogs during peak times (always), we were able to enhance the
policy by using SFQ (stochastic fairness queuing) which is a congestion
control algorithm that works like this:

http://opalsoft.net/qos/DS-25.htm

SFQ has worked very well to allow for youtube/netflix use when the rate
limit is imposed.  This does not exactly address the BT hogs which are
dealt with by other expensive detection and policy enforcement measures but
it greatly reduces the impact of the hogs by fairly allowing time per flow
(as some may recall BT makes a lot of flows).  We have never had a
complaint on this system due to latency.  Most commercial products
implement some type of congestion control (WRED, BROWN, or more intelligent
timers).  The sky is really the limit.

Do you need more bandwidth?  Sure we all do, but would you be better off
ramping up your capacities to support future growth?  For the past 2 yrs,
we have been able to just barely stay ahead of the burden.  In our area of
the planet, high speed links and bandwidth costs are dropping and a 10G
circuit is very reasonably priced.  Getting higher up approval for
additional bandwidth has been an easier case to make given this
institution's migration to Google aps and the shift to higher bandwidth
material to support teaching and learning.

This problem is full of sharp edges.  Not the least of which is the
argument we should manage the resource and have that resource remain
available.  Recall Comcast's lawsuit over approaching a solution to this
problem in much the same way we did in the past and may still.  Here is the
initial complaint:
http://www.freepress.net/docs/fp_pk_comcast_complaint.pdf

Regards,
Josh


-- 
Josh Richard
Information Technology Systems & Services
University of Minnesota Duluth