Why do my new fancy 912 boards show this? Are there really packets being dropped or is it showing how many it has ignored? Also, running packet sniffer will not reveal layer 1 and who is sending these pause packets. How can I track it down?
Sam
Pause Frame is a flow control mechanism to slow down the senders rate.
ROS ignores pause Frames so the mechanism does not work.
You see the pause Frames at lines with different Speeds. So if you send traffic from a 1GBPs Ethernet and
cross a 100MBit or Wireless Segment the router at the border sends pause Frames back to the Sender
when his buffers get filled.
This happens way before the 100MBit in the middle is filled as IP Packets does not arrive evenly spaced.
So a small burst leads to pause Frames. If they are ignored packet drops happen and speeds break down.
I requested flow control from MT. They asked me to ask the Forum if it is needed but there was nearly no Response.
http://forum.mikrotik.com/t/flow-control-in-ros/68224/1
So MT considered flow control as an unwanted feature.
912’s are very touchy on what switch they are plugged into. If its a 10/100 then you will most likely have issues. Most gig switches are ok but we have had issues with pro-curve gig switches and negotiation issues.
RB912 routers drop pause frames because they do not support Ethernet flow control. You cannot see the packets in RB912 sniffer because they do not get to CPU. Normally, directly connected device sends those pause frames.
And what is RX Control?
Everything plugged into that core segment is a routerboard - 411gl, 912, 2011, 750, etc. How can I tell who is sending these? They are interconnected by a netgear 5 or 8 port dumb switch.
As I understand pause Frames are not forwarded by switch/router so it’s the device directly connected.
thats what I can’t understand. Are you saying the mikrotik doesn’t support flow control on the tx but it does on the tx? The only thing in this segment is mikrotik…
MT told me they ignore pause frames. They said nothing on sending them.
ROS 6.12 has this feature. Is it recommended to turn both Tx and Rx FC on or auto? 