Internet Access Update

• To: NIU Local Area Network Administrators
• Subject: Internet Access Update
• From: Gilbert Sebenste <sebenste@xxxxxxxxxxxxxxxxxxxxx>
• Date: Thu, 18 Mar 2004 11:59:28 -0600

Tonight, at around 6 PM, we should be back to "normal", whatever that is, 
as our web caches refill up with banner ads. :-) Fail back to me then. 
Thanks, and sorry. Things are rapidly improving even as I type this.

*******************************************************************************
Gilbert Sebenste                                                     ********
(My opinions only!)                                                  ******
Staff Meteorologist, Northern Illinois University                      ****
E-mail: gilbert@xxxxxxx                                               ***
web: http://weather.admin.niu.edu                                      **
Work phone: 815-753-5492                                                *
*******************************************************************************

---------- Forwarded message ----------
> From: NIU Network Engineering

** High Priority **

The primary degradation in performance that we experienced Tuesday has
been mitigated to some degree.  ITS modified some parameters on the
packet shaper and this modification will take an extended period of time
to have a full affect.  The shaper re-learns packet handling based on
the new parameters and the dynamic traffic.  We also "flushed" the local
cache engine to ensure that locally cached content would not have error
prone content due to the traffic congestion problem.  This resulted in a
self-imposed performance hit as the cache engine re-populates content. 
Checks of bandwidth utilization as relates to certain classes of data
indicates an overall trend of higher traffic which is pushing the limit
of our current bandwidth.  High error rates are not present.  There is
no indication of any equipment failure.  There are minor denial of
service events occurring - but these occur almost all the time and we
deal with them if we can get a handle on a consistent source. We do have
fairly large access control lists in place on the edge routers to block
some of these sources.  Unfortunately, there is a balancing point where
the complexity of the access control lists and power required to process
packet info against them - outweighs the addition of more control
information.  Also, by the time the culprit traffic gets to NIU's
control list screening, the bandwidth has already been used to 
get to us---it competes for incoming traffic bandwidth.

So, in summary, we have done all we can at this point to address the
most recent performance issue.  Performance appears to be improved
today.  We continue to monitor and tune packet shaping efforts and watch
for security related issues.       

J R Fatz
Director, Enterprise Systems Support