What is the status of multicast support in consumer-grade routers

Question

I am developing a system in which there are several small embedded systems, hosts that interact on the local network. UDP multicast is great for my purpose.

But I'm worried about multicast support on regular routers. I need to deploy a system for ordinary households equipped with a Wi-Fi router so that I can run into any type of router. I will use UDP forwarding if multicasting has more problems than good.

To solve, I am grateful for any data or multicast support experience in today's conventional routers:

• Do all consumer router routers sold today support multicast? The LAN restriction is not a problem for me, I do not need multicast over the Internet.
• What about old routers?
• Are there any big problems in normal multicast implementations that I need to know about (for example, packet drops, configuration problems, etc.)?

Answer 1

Are you talking about switches or routers? In the consumer settings, I suspect the switches. My experience is that they support multicast, although not at the speed of transmission. Also, cheap ones tend to forward any multicast traffic to all ports (without IGMP snooping). Packet loss is what you need for a solution, it can and will happen even on "professional" network equipment.

Edit: While you are on a dial-up network, you usually do not need to configure anything.

Answer 2

In many scenarios, the equipment either does not support IGMP spoofing or is disabled by default. There are two problems:

• Any wireless interface can be saturated with traffic.

• Poorly configured devices can inadvertently route traffic from the default gateway, blocking legitimate traffic.

In any case, your equipment will be discarded from you, since the cost of the investigation will almost certainly outweigh the benefits received.

If your traffic has a limited speed and you are not worried about the effect of WiFi, you can use a local broadcast address to ensure delivery to recipients without affecting routing.

You can install a discovery mechanism in your nodes, it may be worthwhile to implement a unidirectional overlay to ensure that traffic does not have an unintended impact.

One large group of customers with some incompatible devices requesting support will cover any costs associated with the development or additional traffic caused by not implementing true multicast.

Answer 3

In the worst case, when routers do not allow multicast traffic, I would encapsulate multicast packets in a unicast IP address. In this way, routers will treat them like regular unicast data. You might want to check out mrouted .

Good luck.