[Tang-residents] [Fwd: Tang Hall Network]

[Jayashree Subramanian]

-------- Forwarded Message --------
From: Stuart Peloquin <peloquin at MIT.EDU>
To: jaya at mit.edu <jaya at mit.edu>
Subject: Email to Tang Hall residents
Date: Fri, 11 Sep 2009 14:54:52 -0400

Dear Tang Hall Residents,


I'm writing to you on behalf of the MIT Residential Computing
Consultants and IS&T.  There have been many reports of slow wired and
wireless problems in Tang Hall and we've received some very helpful
information from the Tang Hall Computer Chair.  We thank those of you
that have reported the problems and appreciate the patience that you've
shown so far as we identify and resolve these issues.  I'd like to take
this opportunity to try and describe the problems and what IS&T is doing
to resolve them.  


Some background information on Tang:


The Tang Hall network consists of wired and wireless devices; each of
these connection types runs on separate hardware that tie into the MIT
backbone at the network entry point to Tang.  Until the traffic leaves
the building, wired and wireless network traffic is not typically
delivered through the same hardware.  The wired network infrastructure
in Tang Hall is aging.  All of the ethernet ports that are in residence
rooms are connected to 10Mbps shared network hubs.  These hubs service
approximately three full floors of residents each.  Meaning that 10Mbps
is shared over approximately 50 resident rooms.  This is sufficient
bandwidth for web surfing, email, IM, reasonable amounts of streaming
video (youtube, hulu, etc…) but cannot accommodate heavy file sharing
such as Bittorrent and similar applications.  


Wireless network in Tang:


As of 8/27/2009 the Tang Hall wireless network has been upgraded to a
completely new infrastructure.  This hardware supports the latest
wireless protocols and is configured dynamically by a central controller
to ensure the best connection possible.  The upgrade has been completed,
but the configuration may need tweaking.  We're eager to hear about how
the wireless connection works in your room and want to know which rooms
the wireless works well in and which it does not.  This will help us
identify what about the current installation should remain and what
should be changed.  We understand there are some residents who are not
able to get a reliable connection and want to attend to those rooms
soon.  


High traffic applications and responsible bandwidth management:


Because of the limitations this infrastructure imposes, we ask all
residents to be mindful of the amount of network data they're using.  On
the wired network, a single resident downloading or sharing a file at
4Mbps (500KBps) effectively uses ~1/2 of the total bandwidth available
to all residents on three nearby floors.  As additional residents start
to use the network, this can create packet collisions and cause your
traffic to be dropped.  When that happens, the packet needs to be
resent.  This behavior, if it continues, can cause connection speeds to
appear intolerably slow.  If you're not sure how to identify the amount
of data you're using, please try to take a moment and think about the
programs you're using online.  If you're moving very large files to and
from other locations on the internet, it's likely this process can
impact the network reliability for other residents.  This includes file
sharing programs like Bittorrent, Kazaa and Limewire.    Some
applications allow you to choose the upload and download speeds
available to the application and we recommend keeping those around
80KBps (640kbps) or lower.


For cases involving slow network connectivity, we request your help.  In
order for us to identify the cause of the high traffic we request that
you report problems to us as soon as possible, ideally while they are
happening.  A key indication that the network problem you are
experiencing is due to high traffic is if it occurs when there are
typically more residents using the network (6pm - 12pm and early
morning), while the situation improves during off-peak time.


Notes on upgrading the wired network infrastructure in Tang:


The hardware installed here cannot be upgraded without also upgrading
all of the network cabling in the building, since the current cabling is
a very old ethernet standard that does not support new switches.
Because of this, upgrading the wired infrastructure in Tang would be a
full scale construction project.   At present, this is not a feasible
option.


Note about the current wired network outage in Tang:


As of earlier this afternoon, there was a known problem with some of the
wired network devices in Tang that we are in the process of
investigating.  There's a number of residents across the entire building
plagued with extremely slow connectivity on the wired network.   For a
few residents, this problem has been occurring over the course of
several days.  


What is IS&T doing about it:


The Residential Computing Consultants have been meeting with residents
and collecting data from on-site and through remote applications to get
a clear picture of the problem.  In the meantime, the network
technicians have been on site in Tang hall a number of times to work
through this outage and come to a speedy resolution.  At this time, we
believe we've identified the cause of the slow wired network connections
and have come to a resolution.  If you are still experiencing problems
with slow connectivity on the wired network, please get in touch with us
as soon as possible.  


Contacting Residential Computing:


The Residential Computing Consultants can be contacted through a web
interface front end at http://rcc.mit.edu.  You can also call
617-258-9444 (on campus x89444).  During business hours, the RCC line is
often answered by a consultant.  Outside of MIT business hours, you will
be directed to voicemail.  RCCs are notified when new voicemail arrives
and will try to get back to you as soon as possible.


Thank you again for your patience and help,




--
Stuart Peloquin
Residential Networking Coordinator
Client Support Services
Information Services and Technology
N42-140U
617 324-6557
peloquin at mit.edu








-- 
Jayashree Subramanian
PDOS, MIT