Video over IP

Video Conferencing over ISDN (vs) Video Conferencing over IP – Which is better?

Obviously you’d think that in this age and time, Video Conferencing over IP is the Best (or) the Only option. But don’t count Video Conferencing over ISDN Out – Yet! In this post, let us look at the advantages of both Video Conferencing over ISDN (and) Video Conferencing over IP Networks.

Before a couple of years, I came across a massive Video Conference system installation of over 225 Video Conferencing systems completely over ISDN network. Their reason for choosing ISDN network? In around 70% of the locations where they were installing the video conferencing systems, IP Network (Internet Leased Lines) were simply not available! But in all the locations, ISDN Lines were available. Of course, most of the locations were small towns spread across the state.

Advantages of Video Conferencing over ISDN:

  • Lower cost of procurement (ISDN lines) and lower recurring usage (bandwidth) costs – especially for low volume video conferencing requirements.
  • Dedicated, Non-fluctuating bandwidth. 128 Kbps in ISDN = 128 Kbps of effective bandwidth, due to lack of packet loss in ISDN networks.
  • ISDN Lines / ISDN Video Conferencing systems could be a good back-up to existing IP Networks – Both for video as well as Internet bandwidth.
  • ISDN is a separate network – So, VC usage will not affect other critical network services like data, voice, etc.
  • ISDN services are available where ever basic phone services are available. Internet Leased Lines/ MPLS Lines are not available everywhere.
  • A four-party multi-conference (including the host) could be comfortably made using four ISDN lines. Of course, each site connects at 128 Kbps.
  • Most of the ISDN based Video Conferencing systems are IP enabled. So, its possible to use them with IP networks later on if required.
  • ISDN Network is a dedicated switched network and hence there is no interference from other forms of traffic. There are no firewall blocking/ NAT traversal issues.
  • Multi-party conferencing / higher bandwidth is possible through ISDN-PRI / T1 / E1 Lines.
  • ISDN gateways can connect ISDN based Video Conferencing systems to the IP Network, if required. But they are quite expensive.
  • While 128 Kbps of ISDN (1 line) might be sufficient for Video Conferencing, broadband connections cannot be used with Video Conferencing systems because the upload and download speeds vary significantly.


Almost all the enterprise companies / large organizations have standardized on IP based Video Conferencing systems. This is partially due to the steep decline in the bandwidth costs and the fact that there is no time based usage limitation for the ordered bandwidth. If at all you want to talk to a partner or a customer, you’ll find that they most probably have IP based Video Conferencing systems.

Advantages of Video Conferencing over IP Network:

  • IP Network is already available for Data transfer / Inter-branch Connectivity (Internet Leased Lines/ MPLS Network) in many organizations. Why not use it for Video too?
  • IP Networks are great for high volume/ frequent video conferences as there is no usage based / time based restrictions (mostly). With ISDN, there are monthly rental charges as well as per-minute usage charges.
  • The bandwidth available in IP networks might fluctuate due to packet loss, but it is easy to upgrade to higher bandwidth. This is especially useful for multi-party video conferencing.
  • IP Network is packet switched network and hence the same WAN connection can be used for multiple conferences as long as the required bandwidth is available and the VC system supports it.
  • Video Conferencing over IP networks is great if you need to frequently keep moving and initiating conferences from many locations.
  • Video Conferencing works over IP networks by default. For ISDN connectivity, additional expensive modules are required.
  • With IP Networks, it is easier to pro-actively monitor the health of both the network as well as the VC system.
  • There is no cost difference between a VC call to Mumbai / VC call to Frankfurt / VC call to Los Angeles over the IP Network. With ISDN, the charges increase with increasing distance between the two parties.
  • Video Conferencing over IP networks are extremely scalable. Its easy to implement desktop video conferencing (for example) to hundreds of users anywhere in the company.
  • QoS – Quality of Service parameters in an IP Network allow some bandwidth to be dedicated for mission critical network applications / video conference sessions.

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  • Nithin Mulley

    “ISDN gateways can connect ISDN based Video Conferencing systems to the IP Network, if required. But they are quite expensive.”

    Yeah this is quite true but it becomes the only choice when you have smaller business divisions in remote locations which are demanded in a video conference. Usually Central location should have the ISDN gateway and remote locations will be calling on the ISDN lines.

    You require the ISDN gateway as the MCU’s support IP bandwidth.

    And also ISDN has the credit of most simple setup compared to IP.

    • admin

      That’s true – remote locations may not have leased lines and they may already be on ISDN. In such a situation we might need the Gateways. But these days, there are lot more options – You can add desktop video conferencing users, mobile 3G video conferencing users, etc to an MCU. Of course, these are for one or two people, not a group.

      ISDN has the credit of simpler setup compared to IP – Absolutely!

      • Richard

        So is it simpler to maintain an ISDN VTC system or VTC system over IP for some one that doesn’t know much about VTC and has a budget of 30,000 to purchase, install VTC system with a 3-year maintenance pkg,and training support/ technical support?

        It will be use often to talk to multiple parties of nomore than 4 systems. I appreciate any advice.

  • John

    Thank you for such excellent information regarding video conferencing over ISDN or IP. We use R-HUB web conferencing servers in our organization for conducting video conferences. It works on both ISDN and IP network.