> Regardless, your problem looks like either tail drops or packet loss, which > you showed originally. The task is to find out where this is occurring, and > which of the two it is. If you want to confirm what is going on, there are > some great bandwidth calculators on the internet which will show you what > bandwidth you can get with a given ms delay and % packet loss. > > As far as flow control, its really outside the scope. If you ever need flow > control, there is usually a specific reason like FCoE, and if not, it's > generally better to just fix the backplane congestion issue if you can, > than ever worry about using FC. The problem with FC isn't node to node, its > when you have node to node to node with additional devices, it isn't smart > enough to discriminate, and can crater your network 3 devices over when it > would be much better to just lose a few packets. > > -Blake
In my experience - if you're traversing licenced microwave links as indicated flow control will definitely need to be ON. Check the radio modem stats to confirm but - if you're seeing lots of drops there you're overflowing the buffers on the radio modem.