Another look at Flow Control in the cloud

I posted about Cisco Flow Control with NetApp NAS during first round of cloud implementation almost two years ago. Paul commented about updates in NetApp documentation, so now is a good time for an update, with a fresh look at the general use of flow control.

Let’s start with NetApp’s “Ethernet Storage Best Practices”, which recommends:

1.  Not enable flow control throughout the network
2. Set storage to “send” flow control, set switch to “receive”

We can all agree on the first point. 802.3x Ethernet Flow Control has not been widely adopted in practice, due to implementation complexity and hardware dependency. Higher layer mechanism such as TCP Windowing, is more predictable and effective for end-to-end flow control.