Videoconferencing: IP or ISDN?

[dan.ring]

Hi everyone,

We are looking to implement video conferencing. We would like to communicate with a remote office in Europe, and also with external partners and customers.

I am interested in opinions or experiences with video conferencing over the Internet, vs. over ISDN. Is v-con over the web between Canada and Europe feasible? What are the majority of companies doing out there? We have a fibre link to the Internet, but the latency to Europe makes me question how the video will look. Help keep us from making a mistake before buying! :)

regards,

Dan

[zfpijewski]

Hi Dan,

I've been using a Tandberg 6000 Video Conference system between our sites. The VC over IP has been working fine, and at times better then ISDN. There is some latency between our Cambridge MA site, and the UK, but it isn't to bad. BW is 768K for the Video Conference, (total BW for all traffic is 6MB) through a VPN tunnel between the sites. Having multi sites connected VIA IP works well, both Tandberg and Polycom. Our prefered method is IP, with ISDN as a backup.

Regards,

Ziggy

[msdavis]

I have been using it for some time from California to Germany and Italy with Polycom equipment and have had good results.

The latency is there, but I think there is a an inherrant acceptance of turn-around time with Video Conferences. There is a sense or courtesy that even on local "calls" that develops - "now it is your turn to talk".

I can notice the latency, but the users have not complained. If there is packet loss or excessive jitter, they make more comments about the screen pixilating, which happens about the same frequency on ISDN. When you think about a 384K call, that is 6 - 64K ISDN "calls." With that many International calls going on at the same time, you can imagine that one of those could have static or other problems.

As for the purchase decision, I would try to get a unit that can do both. We use IP for most of our internal conferences, and ISDN for video conferences with outside partners.

--Michael

[sachon]

The ROI of IP over ISDN is compelling. Access, WAN b/w, manageability, etc... are all easier and less expensive. As for video over the Internet, Cisco suggests a QoS-based VPN type-offering to achieve high-quality, secure communications.

As for latency, there are 2 main causes ... encode/decode by the video codecs and WAN transport. Not much you can do about WAN transport - your SP may be able to minimize this by limiting router hops, defining shortest path etc... Codecs have a little more flexibility. Some allow you to adjust metrics such as jitter buffers which may help.

[aljaz]

ISDN conf can provide you stable tailored conference for higher cost. You can deal between quality and price from single 64kbit/s (15f/s low resolution) channel up to 6x64kbit/s (industrial quality) channels for five to six times higher cost. If you need quality for shorter periods of time this is better solution. With IP as transport you can provide more flexibility and lower cost (average). For connections between continets you have first to check if internet can serve as transport media. Basically, you have to locate end points close to larger nodes with direct connection to other continent. For all other locations, you can use internet only for low quality low reliable conferences (friends and closely working professionals). The most efficient solution is IP conference over leased (nailed-up if used only for conference) lines or private IP network with QoS control. This solution is used by most of companies with business critical konference applications.