RAVEN at
Mayland Community College
Technology Enhancement Grant:
NCIH on DSL Project

View the presentation MCC made at the March 11, 2004 meeting of the North Carolina Distance Learning Alliance (NCDLA) here.

The following DSL project was part of a Technology Enhancement Grant funded by the North Carolina Community College System:

The objective was to connect an Interactive Television (ITV) classroom in our new Avery Campus facility in Newland, N.C. with the North Carolina Information Highway (NCIH) using a Digital Subscriber Line (DSL).

First we consulted with the NCIH staff. This project could not have happened had it not been for their willingness, dedication and hard work. Next we contacted Bell South FastAccess, and arranged for the installation of a Business Class DSL line which provides 768 Kbps downstream and 512 Kbps upstream.  The 384 Kbsp speed video that we are running has some overhead for the H.323 packets and requires a total bandwidth of about 490 Kbps full duplex (up and down at the same time).  We use the extra bandwidth for the data needs for rest of the Avery Campus.

Performance Data installed a Cisco 827 router that provides Quality of Service (QOS) within our Local Area Network (LAN), so that when H.323 (IP Video) traffic is present sufficient bandwidth is reserved for the videoconferencing.  When we are not using the video, all of the bandwidth is available for data.  If you do not need the DSL for data elsewhere, you could use the Cayman 3200-H Router that Southern Bell sells (it worked fine for video or data only).  The Cisco 827 also provided us a firewall and Network Address Translation (NAT).

The only problem we had with the networking was when the video codec was left to auto-configure the LAN speed.  The codec would auto-configure to 100 full when it communicated with the Cisco 2948G switch.  The switch would send the packets to the router which operates at 10Mbps.  We found that by forcing the codec speed to 10 half we had the best results for our set up. Mayland has chosen VisiCom as our room integrator for all of our video conferencing rooms.  They have been wonderful to work with in pre-planning, implementation and troubleshooting.  With such a unique mix of equipment, we developed a persistent audio artifact that was ultimately eliminated with a patch for the VTEL software.

DMA Video/ Data Networks, Inc.  provided us with expert training in the setup and use of equipment using the H.323 protocol.  They suggested that we use the Easy-VC 107 Packet Master to solve video freezing that sometimes occurs in the late afternoon when the Internet is at its busiest and we are not using the NCIH.  This equipment (not part of the TEG grant) compensates for some late packet delivery between two or more sites using the equipment.

Mayland was able to use this technology to deliver three courses in the Spring Semester of 2003 and we offered four courses in the Spring Semester 2004.   We feel that the DSL technology can best be used by low volume sites (under 20 hours a month) and by new sites who want to explore their possiblites with out committing themselves to spending a lot of money.  DSL installation and activation costs us $250.00 which is about a tenth of the installation fee of a regular NCIH connection.  Our monthly DSL bill is $219.95 (Bell South gave us two months free during a promotion)  which is about a tenth of a regular NCIH connection.  The fee to connect to the NCIH is $35.00 per hour.  We are planning on using the ITV room in our Avery Campus a lot more than 35 hours a month, so it will make sense for us to pursue a full connection.

I  have created two spread sheets that look at potential saving (for calendar year 2003) for moving to this type of technology.  One looks at Community College sites and one looks at all NCIH sites.  I have made some broad assumptions about all sites paying the same for access and other costs (assumptions listed on sheets), but you can see for your self that there could be some significant savings if other users adopted this approach.  ITS is currently in the process of switching all NCIH sites over to the newer H.323 technology.

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