Simple Multicasting With An Unmanaged Switch?

Imagine you had 15 public view monitors/pc's all displaying one camera, 24/7. All connected to the same unmanaged switch. Maybe around a hotel hallway?

Would it be possible to multi-cast from the camera to all monitors/pc's using the unmanaged switch and no other hardware?

If possible, would it be desirable?


If the switch support IGMP Snooping, then yes you can multicultural to all of these locations. Some switches require a mid-tier model, such as a Web or smart switch, which has some web-based management and allows IGMP Snooping.

Agree, if it supports snooping, it should work.

But, I am actually talking about a pure layer 2 switch, whose only configuration options are limited to power on or off.

Yes it is possible. You can pass multicast traffic on a completely unmanaged switch. The lack of IGMP means that the multicast traffic will be treated like broadcast traffic and sent out on every port on the switch except the port the traffic originated from.

Desirable depends on your situation. If you have an isolated network with only the camera and TVs and you are only talking about a low amount of bandwidth you should be fine.

However once you add other devices to the network or connect to a router you are now exposing yourself to problems:

  1. Since every device on your network is going to receive the packets, they all have to process the packet header and drop them. This is going to increase the CPU load on devices like your router.
  2. If you have Wi-Fi access points that are not multicast aware they could broadcast the traffic over your Wi-Fi network as well.
  3. Adding an additional unmanaged switch as an uplink with now broadcast the packets over every port on that switch as well.

FWIW, I'm not sure IGMP snooping on its own with a querier, would work to segregate the network traffic to only the ports that are using the multicast. Layer 3 switches usually have both snoopers and queriers.

www.singlewire.com has a free Multi casting Server and Test Tools.