Questions · Networks
What is multicast and when is it needed?
It is sending one single copy of the video and letting the network share it out among those who ask for it. If ten workstations watch the same camera live, without multicast the camera or the server send ten copies; with multicast they send one.
It is needed when there are many viewers of the same live feed: a control room, a video wall, several monitoring workstations watching the same thing. With two or three people watching, the complication it adds is hardly ever worth it.
And if it is used, it has to be configured properly. Without IGMP snooping on the switches, multicast is treated as if it were for everybody and sent out of every port: it is the quickest way to flood a network and to bring down things that have nothing to do with the cameras. You also have to decide who acts as the group querier, because if nobody does, the distribution collapses on its own after a while.
Where it is set out in full.
All the questions.
Five hundred and forty-four, grouped by topic. Each with its own page.
Get started
See it working.
A written answer is enough to decide whether it interests you. To know whether it works at your site you have to see it on a real scene, with the image as it is and, on top of it, what the system understands from it. That is on the IRIS Neural website, which is the group's product.