Re: [EFM] flow control in 802.3
What a good question!
This is a problem that we (almost certainly) have to solve in the copper track. We are looking for suggestions, the ones that immediately come to mind are:
MII clock adjustment
.3x pause frames
half-duplex back pressure (force collision)
new signal for pause/continue
The matter was discussed at length during .3ae - take a look at 10G website...
There are various other discussions of this on 10G. It's not clear that the arguments and conclusions are valid for .3ah in the same way as .3ae - but it's always worth taking a look.
PS - Any of the 10G'ers care to comment?
MARC KIMPE wrote:
> Is there a way to transmit flow control information across an MII interface from the PHY direction to the MAC ? If yes could someone point me to the pertaining clause of 802.3 ?
> In other words, let's assume that a PHY for some reason or other can only transmit at 3Mbps while information to that PHY flows at 10Mbps. How can the PHY tell the MAC to stop sending ? I saw some presentations related to 10 Gigabit Ethernet that proposed various mechanisms but I do not know if anything was adopted.
> Any help would be appreciated.
> Marc Kimpe