A socket happens at layer 5 of the OSI model. Ethernet Flow Control happens at layer 2.
Flow control enables you to manage the flow of frames between two directly connected link-partners. Flow control can reduce or eliminate dropped packets due to overrun.
To achieve flow control, you can specify a flow control option that causes packets called Pause frames to be used as needed. For example, link-partner A sends a Pause On frame to link-partner B when its receive buffers are nearly full. Link-partner B suspends transmission until it receives a Pause Off frame from link-partner A or a specified timeout threshold is reached.
http://now.netapp.com/NOW/knowledge/docs/ontap/rel733/html/ontap/nag/GUID-ED84D07C-609C-44E5-AC75-6E7FF282B557.html
This sounds like what you are experiencing. Turn on Ethernet flow control and your issue should go away.
Thanks,
Mitchell