This post continues our 20 Day Challenge to understand the technical aspects of videoconferencing.
VC is a good test of the health of your network. If you have poor or unacceptable video quality, then check for these things:
1. Quality of Ethernet Cable
Make sure you have a good Ethernet cable. No crinks or folds or twists. Make sure it hasn’t been run over by the cart too many times! (For the vendors reading this, yes, this is an issue in K12 schools!)
2. Hubs in the Network Path
Replace any hubs in the path of the video conference traffic. Hubs seriously deteriorate the quality of the connection. Replace them!
3. Filter Settings.
We have all experienced odd behaviors and weird symptoms of videoconferences that ended up being the fault of the filter. Make sure the filter is allowing all necessary traffic to the videoconference systems. Review this port list if needed.
4. Excessive Bandwidth Use Behaviors
One common challenge in bandwidth-starved districts is the use of streaming video tools such as Discovery Education streaming and similar services. On a full-bandwidth network, someone live streaming a video can clobber the quality of the videoconference occurring at the same time. A solution used in Berrien RESA’s service area is to turn off the ability for teachers to live-stream the videos. Instead they must order their videos to be downloaded at night.
Another unfortunate challenge in some districts is that of computer labs used by students without appropriate supervision.
- Students playing online multi-player games
- Downloading large software files
- Downloading large movies
- Downloading music collections
All these cause havoc on the bandwidth usage.
Do what it takes (technological or political solutions) to make sure that non-academic use of technology doesn’t interfere with real engaging learning experiences.
5. Conflicting Router Settings
10/100 M and Full/Half Duplex Settings
The 10/100M or Full/half duplex settings on the router need to match those settings on the endpoint. When these settings don’t match, the endpoint and the router are constantly negotiating how to communicate and therefore using up processing power and bandwidth, which causes horrible quality. There was a time a few years ago in videoconferencing where it was recommended to hard set both of them to the highest that the router could do. However, with newer routers, generally you’ll get the best success with both set to auto. Experiment to see which works best if necessary.
Timeout Limits
Review the time out limits on the router or the wireless access points. If a call drops consistently after a set amount of time, this could be a timeout limit somewhere in the network path of the videoconference. When the videoconference call starts, the two endpoints communicate on certain ports; but after that, the communication happens on the audio/video streaming ports. In some cases, the router thinks that the connection is no longer being used, so it ends the call. Check the settings!
Cohesive NAT settings
If you’re using the NAT solution, make sure the NAT settings are cohesive on the firewall / router and endpoint. We have all seen situations where the settings are good enough that calls occur, but the quality is poor. Making sure the settings are correct improves the quality. In particular, check the “fixed ports” and “firewall is H.323 compatible” settings. Experiment if necessary to see which settings work best.
References
Your Turn
- Have you noticed any of these challenges? How did you solve them?
- What other problems would you add to this list? Please comment!
Team-written by Janine Lim, Shane Howard, and Roxanne Glaser. The opinions expressed in these posts are based on our collective video conference experience connecting classes across multiple networks to connect them to zoos, museums, experts and other classes during the past 10 years. This series of posts reflects our usage and understanding, not that of any vendor or manufacturer. No one is paying us to write these. We are just sharing what we have learned.
