Long Distance Fibre Channel Link Tuning
In this video I talk about some of the variables involved in long distance link tuning of fibre-channel distance links. In this blog post I'll detail some of the tools that are available. I will also provide an example of estimating the number of buffer credits you will need. Note that this tuning is only for fibre-channel links. This does not apply to FCIP tunnels or circuits. One critical piece of information that you will need to calculate buffer credits is the frame size. Smaller frames means more of them can fit in the link, so you would need more buffer credits. Of the variables that go into the formula, this is the only unknown. Everything else is either known or is a constant. Brocade has the 'portbuffershow' command that can tell you the average frame size for a link. You would look at the Framesize columns for TX and RX in the portbuffershow output to get the frame size. The portbuffershow output is organized by logical switch and then by port. O