How many SwitchBlox can I daisy chain together?

– Copied from a customer query –

I want to know if I can connect a large number of SwitchBlox in series and whether custom software is needed. What is the maximum number of SwitchBlox that can be connected?

This question is not really SwitchBlox specific. SwitchBlox acts just like a standard switch, so the answer here is the answer of any standard unmanaged 10/100Mbps switch.

You can connect multiple SwitchBlox in series. In theory, no additional software is needed, and all devices on the network will be able to see each other. However, the daisy chain connections mean we have to consider data rate limitations.

The maximum number of connections depends on the data rate of your devices. Excessive daisy-chaining might lead to lost packets or high latencies. This is because each daisy chain connection is a bottleneck to data.

For example, all five ports on the same SwitchBlox can send and receive 100Mbps simultaneously to each other. This is because the chip used on SwitchBlox has a non-blocking fabric, such that it is able to handle simultaneous data transfer between all ports.

The situation changes when you use a daisy chain connection. A daisy chain connection between two switches is limited to the single port speed of the switch, in this case, 100Mbps.

You can imagine a situation where three devices on switch 1 want to send 3 streams of 100Mbps to a device on switch 2. That would be an aggregate rate of 300Mbps through the daisy chain connection, which would exceed the maximum bandwidth. In this case you’d get packet loss at best and network drops at worst.

I plan to use SwitchBlox in a car parking system. Could you advise on the type of camera and the number of cameras that can be efficiently supported?

For a parking system, the choice of camera is crucial. I recommend not daisy-chaining more than 3 switches at a time. The specifics depend on the data flow in your network. The camera’s data rate and compression standards will play a significant role.

I am considering using a camera with 10/100Mbps ethernet capability and plan to have around 100 cameras. I’m thinking of alternating the photo capture instead of simultaneous shooting.

With 100 cameras, it’s important to consider the real data rate from each camera. You might need to control the cameras carefully. Alternating photo capture is a good approach. You need to be mindful of the bottlenecks in connections between SwitchBlox.

Let’s say each camera uses a compression standard H.265 720p. A quick google search suggests that you’d need around 10Mbps of bandwidth for this (I’m no expert in video compression standards so I could be wrong here).

In this case, one could imagine that, in your network, three camera ports on SwitchBlox 1 could easily send to a device on SwitchBlox 2 through the daisy chain connection, because the aggregate rate on the daisy chain port is 30Mbps.

However as you add more and more daisy chained switched, you can imagine you’ll get to a point where you’ll exceed the daisy chain bottlenecks.

The way to do this is, as you say, request data from each of the 100 camera only when needed, and ensure they are not sending data out unless requested. This would require some software running on the main PC you are using to co-ordinate this network.

Hope that helps.

Thank you really for the detailed advice. I will try this setup and let you know the results.