Troubleshooting a Timeout Problem

Ever had a videoconference drop after a consistent amount of time (i.e. 15 or 20 minutes) all the time? I have two districts struggling with this problem right now.

Timeout by deovolenti

How do YOU troubleshoot a time out problem?

Here’s what I do. Remember that I’m not a network person! I don’t know exactly how to fix the router or firewall settings. But I can help our district network techs know what to look for!

Check the Settings on the Endpoint

First, almost all videoconference systems have a maximum time in call setting.

On the Polycom VSX 7000, it’s under System, Admin Settings, General Settings, System Settings, Call Settings, Maximum Time in a Call. I usually set this as high as it can go.

Check the Settings on Firewalls & Routers

Next, if that didn’t fix it, I talk to the network techs and give them some ideas of what to look for.

Since I really have no idea how to change settings on a firewall or router, I can really only explain what happens during the videoconference call.

  • The call is set up on port 1720. The two codecs do a caps exchange (capability exchange) and negotiate the media ports to use during the videoconference. (If a gatekeeper is involved in the connect, ports 1718 and 1719 may be used also.)
  • Then after the call is set up, the traffic switches over to the ports that are used for the media traffic. We usually have our Polycom VSX 7000s set to “fixed ports” which means it should be communicating in the range of TCP 3230-3235 and UDP 3230 to 3253. You can find a fairly comprehensive list of ports used in VCs here.

Sometimes if the router or firewall isn’t seeing any traffic, it may close the ports thinking that the call has ended when really it hasn’t.

This info usually helps my techs enough to figure it out from there.

What about you?

Have you ever run into a problem with videoconferences ending after a specific amount of time consistently? How did you solve it?


About Janine Lim

Janine Lim, PhD, currently serves as associate dean for online higher education in the School of Distance Education at Andrews University, in Berrien Springs, MI. She and her team support over 200 online courses, provide training for faculty teaching online, and work with the campus infrastructure support of online learning. Her department also provides educational technology and Moodle support for faculty and students. In addition, Janine is responsible for the faculty and courses of the Consortium of Adventist Colleges and Universities. Janine has taught over 15 unique graduate educational technology classes online numerous times over the past 15 years, with some classes attracting participants from all over the world. Her undergraduate teaching includes social media courses for communication and digital media majors. Janine has served on the board of the United States Distance Learning Association since April 2015. Prior to her work at Andrews University, Janine coordinated distance education for 22 K12 school districts in southwest Michigan for 14 years. In that position, as one of the co-founders of TWICE, Michigan’s K12 Videoconferencing Organization, Janine has spearheaded popular international K12 videoconference projects such as Read Around the Planet and MysteryQuest. While still serving on the board of TWICE, she was instrumental in designing and implementing the CAPspace website for collaborative videoconference projects. Janine also served on a team of Michigan educational technology trainers providing a workshop called ATA Technology Academy. Her current online learning research interests include successful teacher behaviors, quality online discussions, and student activity patterns in self-paced courses.
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