Videoconferencing General Information

Videoconferencing Resources

Supported Video Collaboration Tools
For More Information
Cisco Webex
Blackboard Collaborate
 (Blackboard Collaborate is available through My UW Madison)
Telepresence and H.323
Adobe Connect
Google Hangouts as part of Google Apps for UW

UW-Madison offers Cisco Webex to all University Staff and Student Help.  Employees can use Cisco Webex Teams & Cisco Webex Meetings as part of this service.

Current video devices that are supported by DoIT include:

UW Extension Instructional Communications Systems (ICS), located at the Pyle Center, has several audio and video conferencing services.

  • H.323 Gatekeeper1 that is open to all in the UW System at no cost.   Use of this gatekeeper is necessary to use the Global Dialing Scheme2.
  • Contact ICS for Cisco Jabber Video software and licenses.
  • ICS also offers Blackboard Collaborate, a software-based videoconferencing technology.
  • ICS operates the UW System Administrative Videoconferencing Network.  AVN Help Guide
  • ICS has a standard definition Polycom at for test calls. This can be used to test your H.323 videoconference equipment.
  • ICS also offers Pexip video conferencing under the WisLine Anytime Video brand.

To use the ICS Gatekeeper:

As a courtesy, contact ICS and let them know you'll be using them (800-442-4614 or Then go into the system settings menu into the H.323 settings and set the gatekeeper address to

If you would like to use a so-called E164 number (this is optional), ask ICS to set a number aside for you. It will be in the form of 160826568xy. When you get that from ICS, enter it in your system as the H.323 number.

You can make up your own name, like, and enter it in the H.323 name field, saving as necessary. You can make up any name you want, but append a domain name like so that you can receive incoming calls.  I highly recommend that you use a rich, descriptive name to make finding you and troubleshooting your system easier.

You can't make up the domain name part of this identifier.  In order to receive incoming calls from outside video devices using names on the ICS gatekeeper, those outside devices need to be able to find the gatekeeper. This is done by adding SRV records to the dns server serving the subdomain. There are already SRV records in the domains and  If you would like to use a different subdomain, contact me.

Check you info screen and see if it shows the system registering successfully.

note 1: A Gatekeeper lets you refer to a videoconference device with a number (an E164 number - like a telephone number) or a name. Gatekeepers came about as a way to let ISDN video codecs call IP video codecs. Another advantage of using a gatekeeper is that a codec can be moved to areas with different IP addresses while still keeping the same E164 number.  Gatekeepers support easy calling between video devices registered to the gatekeeper.

Also, by restricting your video conference device to using a gatekeeper, the gatekeeper can be configured to block unwanted (spam) video calls.

note 2: The Global Dialing Scheme (GDS) is a specification developed by the now inactive Video Development group ViDe. It specifies how Gatekeepers can be linked together globally (similar to the Internet Domain Name System) to create an international numbering system for video conferencing equipment. GDS grew out of the H.323 world, and is not interoperable with classic Cisco TelePresence or SIP.  GDS numbers in the US can be distinguished from SIP numbers because they include a leading 001 country code.

Internet2 operates a Video Exchange.
Our goal is to facilitate high-quality communications technologies that leverage advanced networking. To this end, we operate a national video exchange to facilitate easy and cohesive telephone style dialing for advanced videoconferencing and telepresence. Our core signaling strategy is based upon ENUM and, with continuing support for the Global Dialing Scheme and SIP trunking. This combination of services in conjunction with advanced telepresence bridging and carrier peerings provides a core infrastructure that the broader research and education community can leverage to achieve unified dialing and reachability across diverse protocols, and across the world.

There are several ways to dial video conference calls:

  • H.323
    • by IP address (
    • by DNS Name (
    • by E164 number (16083164500)
    • by GDS2 number (0016083164500)
    • by URI3
      • 16082656863@
  • SIP 4
    • by E164 number (16083164500)
      • classic TelePresence rooms can ONLY dial E164 numbers
    • by URI
      • 16082656863@

note 3: Uniform Resource Identifier (URI) is defined by an Internet RFC. As used in video collaboration, a URI consists of a left-hand side, an @ sign, and a right-hand side. The left-hand side can be a user name or an E164 style number, like a SIP or GDS number. The right-hand side can be a Domain Name like or an IP address.  The advantage of using a URI in video collaboration is that the user does not need to have the central network or video conferencing people explicitly configure a relationship with the server at the call destination -  the URI contains the address of the Gatekeeper or Video Communications Server (VCS) that is needed for the call.  The Internet2 Video community encourages the URI method of call dialing, because it usually has fewer local configuration dependancies than IP Addresses or the GDS. 

note 4: Session Initiation Protocol (SIP) evolved as a way to support voice over IP and was adopted by the video collaboration community.  Compared to H.323 dialing, SIP is easier to use behind a firewall because it uses a single TCP Port.  Most modern video conference devices can be configured to use H.323, SIP and URI schemes.

Easy videoconferencing can be done with consumer-oriented technologies like Apple Facetime, AOL Instant Messenger (AIM), Yahoo Instant Messenger, Skype, Google Hangouts, and others.

H.323 videoconference devices can connect to one other device. To connect more than two endpoints, a Multipoint Control Unit (MCU) is used.  ICS (see above) operates MCUs.  Internet2 (see above) operates MCUs.

The H.323 protocol has some behaviors which are a challenge for firewalls and Network Address Translation (NAT). The protocol responds to call origination on different ports, and embeds IP addresses within packets. There are three ways to respond:

  • Use a firewall that explicitly supports H.323 protocol, opening up the needed ports, and re-writing embedded IP addresses. The Cisco FWSM explicitly supports H.323 if the correct rule is used.
  • Install a hardware device that manages H.323 devices inside a firewall.
  • Put the H.323 device outside the firewall. (This is not a significant risk with hardware codecs, as these are special-purpose appliances, not general purpose computers. This is not a good alternative with software codecs.)

VideoLAN VLC is free, general-purpose, open-source software for encoding and decoding video. VideoLAN can send out the desktop as a video stream. Using this method, slide shows like Powerpoint can be shared with others.

Access Grid is free open-source videoconferencing software. The UW-Madison Computer Science Department operates an accessgrid node.

The Videoconferencing Cookbook from the now inactive ViDe group.

Microsoft Research created ConferenceXP, a software-based videoconferencing technology. ConferenceXP is open source software. Much ConferenceXP development is happening at the University of Washington Center for Collaborative Technologies.

The WIDE project in Japan has developed DVTS (Digital Video (DV) over IP). There are standard definition and high definition versions of DVTS. DVTS requires high bandwidth - 20 Mbps.

Wainhouse Research analyzes the market trends, technologies/products, vendors, applications, and related services in the Unified Communications and rich media conferencing fields.

WebRTC is an open source real-time-communications effort. This could revolutionize video conferencing by building video conferencing tools into web browsers, similar to the HTML5 standard.

Vendors of software, equipment and services
  • Avaya (formerly Radvision) hardware and software, including Scopia Desktop
  • Blue Jeans Cloud-based multi-point conferencing and Skype to H.323 
  • Cisco TelePresence (and former Tandberg) products; hardware and software H.323 codecs; immersive, room individual, iPhone/iPad
  • CiscoJabberVideo5 a free, cloud-hosted version of Jabber Video (former Tandber Movi)
  • Iocom commercial implementation of Access Grid
  • Lifesize a division of Logitech
  • Lync Unified Communications (presence, IM, audio, video), Microsoft product
  • Mirial
  • Polycom hardware and software H.323 codecs; immersive, room individual, iPhone/iPad/Android
  • SeeVogh child of EVO, child of VRVS
  • Skype known as a free audio and video client, paid options for multipoint use;  Microsoft product
  • Vidyo a videoconferencing system with hardware central equipment and soft clients. The Internet2 Commons has demo Vidyo services.
  • VSee software video conferencing

A note about Skype: Skype is often considered for conferences with remote sites because people are familiar with Skype because they use it personally or because it is widely recognized as a free conferencing product. Skype uses peer-to-peer technology. That means that the Skype software on your computer may also relay other Skype calls to other locations for other users, and your video call may relay through other Skype users' computers. One impact of this is that this technology is non-deterministic - the path a Skype call takes will be different from one day to the next. In addition, if a user whose computer is being used to relay a Skype call ends their Skype program, the path for the in-progress Skype call will need to be re-provisioned. This may cause a drop in quality of a call in progress, or even cause a call to drop. Another impact of the peer-to-peer technology of Skype is that it potentially makes UW-owned computing resources available to non-UW users.  Skype is also a proprietary protocol.  That means that to bridge between Skype and H.323 requires a bridge that uses a method licensed by Skype.  The only company that I know of at this time that provides such a bridge is Blue Jeans Networks (see above).

Another drawback of Skype is that its technology is proprietary - not standards-based. Skype is not interoperable with H.323.  Blue Jeans offers transcoding between Skype and H.323, but Blue Jeans is a paid service.  I am frequently asked to support video calls with Skype as the remote technology and a room-based Polycom or Cisco Tandberg endpoint here on campus.  I don't know of a no-cost way to do that.  But Cisco and Polycom do have free cross-platform video clients which are standards-based, and which do work on Cisco and Polycom endpoints here on campus.  Campus departments can recommend that remote callers can use free Cisco or Polycom clients to make calls to our campus endpoints.

note 5: is way to get a free video conferencing client that runs on your computer and is hosted in Cisco's server cloud. This is a great way to hold job interviews for remote applicants. The process is to send the candidate an email with a link to, and another link to your video conference device.  The candidate would go to, register for a free account, download and install the software, enter their username and password, and be ready to make calls.  The candidate could click on the link to your video conference device in the email, and the call would be placed.

For example, I would use the link to call the Jabber Video on my desktop, or to call the Polycom in room 3139.

Video Conference Test Numbers

UW Whitewater

Video Collaboration Resources at UW-Madison
creation in progress - to add rooms or suggest revisions, click on Comment link at the bottom of this article
Building Room Host Department Equipment Availability Contact
Computer Sciences 3139A DoIT Polycom HDX
Cisco Webex Share
DoIT Departmental Use CIO Program Assistants
Network Applications
Computer Sciences 3139BDoIT Cisco Webex Share DoIT Departmental Use Network Applications 
Computer Sciences 3139C DoIT Cisco Webex Share DoIT Departmental Use Network Applications 
Computer Sciences 2147 DoIT Polycom VSX DoIT Departmental Use CIO Program Assistants
Computer Sciences2281DoIT Cisco Room Kit DoIT Departmental Use Network Applications 
Computer Sciences B106 DoIT Cisco Webex Share DoIT Departmental Use Network Applications 
Computer Sciences B109 DoIT Cisco Webex Share DoIT Departmental Use Network Applications 
Computer Sciences B122 DoIT Cisco Webex Board 55 DoIT Departmental Use Network Applications 
634 W Main 105 DoIT Cisco Room Kit Mini DoIT Departmental Use Network Applications 
634 W Main 106 DoIT Cisco Room Kit Mini DoIT Departmental Use Network Applications 
634 W Main 117 DoIT Cisco Room Kit Mini DoIT Departmental Use Network Applications 
634 W Main 118 DoIT Cisco Room Kit Mini DoIT Departmental Use Network Applications 
634 W Main 119 DoIT Cisco Room Kit Mini DoIT Departmental Use Network Applications 
Rust/Schreiner 139 DoIT Cisco TelePresence MX300 G2 DoIT Departmental Use Network Applications
WIDMIR   WID Cisco TelePresence CTS 3210 By appointment see  [Link for document 18532 is unavailable at this time.]
Education L138 Education: MERIT Cisco TelePresence CTS 3210 By appointment see  [Link for document 18532 is unavailable at this time.]
Gen Biotechnology Ctr 1132A Biotechnology Center Cisco Room Kit Mini Departmental Use Richard Kunert 
Meat Sciences 1111 Cisco Webex Codec Pro  Stephen Switzer 
Meat Sciences 1115  Cisco Webex Codec Pro  Stephen Switzer 
Van Hise 290 L&S: Learning Support Services Cisco C40 by reservation, primarily for L&S instruction and CIC CourseShare Courses David Macasaet
Bascom Hall 53 
Cisco Room Kit Mini   Network Applications 
21 N. Park 7406 Continuing Studies Cisco Room Kit Departmental Use William Tishler 
21 N. Park 7428 Continuing Studies Cisco Room Kit Departmental Use William Tishler  
Nicholas Rec 312B Rec Sports Cisco Webex Share Departmental Use Amy Meyer 
Nicholas Rec 312C Rec Sports  Cisco Webex Share Departmental Use Amy Meyer 
Nicholas Rec 312G Rec Sports  Cisco Webex Share Departmental Use Amy Meyer 
Nicholas Rec 312H Rec Sports  Cisco Webex Share Departmental Use Amy Meyer 
Nicholas Rec LL319Rec Sports  Cisco Webex Share Departmental Use Amy Meyer 
Nicholas Rec  LL155B Rec Sports  Cisco Webex Share Departmental Use Amy Meyer 
Nicholas Rec  Peloton Rec Sports  Cisco Webex Share Departmental Use Amy Meyer 
Nicholas Rec HuddleRec Sports  Cisco Webex Share Departmental Use Amy Meyer 
Computer Sciences   Computer Sciences Access Grid by appointment CS Access Grid Info
Pyle Center several Instructional Communications Systems several by appointment, fee see ICS web site Videoconferencing
School of Nursing several School of Nursing Polycom by reservation Classroom Support
Science Hall 140 Nelson Institute Cisco MX800 SpeakerTrack for departmental use Kelly Conforti Rupp (608)265-5296

Keywords:video, conference, Polycom, cisco, telepresence, sip, h.323, videoconference, videoconferencing, skype, jabber, video, tandberg, lync video conference conferencing general information   Doc ID:12527
Owner:Shawn T.Group:Network Services
Created:2009-10-29 19:00 CDTUpdated:2021-02-03 11:26 CDT
Sites:Network Services, Telepresence
Feedback:  13   2