The server on the WAN could be the server of a Content Delivery Network [CDN], such as Ustream, LiveStream or Justin.tv. To use a CDN you may need to register for a free / trial account first and then some costs may be involved at a later stage. You only provide one video stream to the CDN and they share that IP video feed with multiple viewers. This means less work for you and the NVS-20 too. CDNs differ in tariffs and the way they operate so it is best to do your own research beforehand.