Lets say I have 2 switches and 2-2 devices connected to each switch.
Each device sends data to other devices in a cylic manner for example Device1 sends data at 100msec, device 2 at 200ms.
So i want to calculate the required bandwidth for each device and switch if the data size sent is approx 2000bytes.
So now in my simulation I have given bandwidth values of 10Mbps, but after certain period lets say after 1 minute of simulation.. switch buffer starts filling up and messages are getting droped.
So in my conclusion i think bandwith is the problem because messages are not sent or accepted with required bitrates.
So I want to calculate bandwith of each device and switch.enter image description here
2000 bytes every 100 ms is 2000 * 8 / .1 = 160 kbit/s. If you've got four such sources, you're using roughly 6.5% of a 10 Mbit/s link.
Even if each device unicasts that amount to each of the three others, that total bandwidth is only tripled. Only half of those unicasts (~1 Mbit/s) cross the switch interconnect which is your bottleneck. Also, modern Ethernet is full duplex, so a 10 Mbit/s interface can transmit 10 Mbit/s and receive 10 Mbit/s at the same time.
Of course, a better approach would be to use multicast. That way, each data chunk is only propagated through the network in a single instance.
If your network goes down after a few seconds, then the parameters above or the diagram aren't correct, or the simulation is flawed.