Re: disabling mediaopts for if_wm(4)

[David Young <dyoung%pobox.com@localhost>]

On Wed, May 10, 2017 at 09:35:44AM +0800, Paul Goyette wrote:
> Well, I got a little bit of a problem...
> 
> My new fiber-to-the-home router only has one RJ45 port available, so
> I had to get a switch to connect all of the hard-wired network
> devices. It all seems to work, except for one problem...
> 
> In the uplink direction, I can only push about 3.5Mb/sec, compared
> to the expected 50Mb/sec in the download direction.  And, if I
> directly connect to the router's RJ45 port I can also get 50Mb/sec
> upload speed.
> 
> So, the upload problem happens only with the switch.

ISTR that wm(4) has one or more bugs concerning flow control.  It's
possible that when flow control is negotiated, the MAC is not set up to
respect flow control signals, so it keeps sends frames to the peer after
it is asked to pause.  With all buffers full, the peer drops the frames
on the floor.  This would be an important bug to fix.

Does your switch tell how many frames are dropped?

Dave

-- 
David Young
dyoung%pobox.com@localhost    Urbana, IL    (217) 721-9981