Hello,
I got some problems with the port switching setup on RB493AH. I have switch setup among eht3, eth4, eth5 where eth3 is master port. Eth4 and eth5 has eth3 as master port in the configuration. To all three ports were connected computers with 100Mbit ehternet card and everything was working well. However at this moment I connected to eth5 VoIP gateway linksys and I started to have very big problems with internet connection speed. What I discovered is that linksys requiere 10Mbit halfduplex. This speed is negotiated on the eth5 where linksys is connected (manual setup to any of another speed or fullduplex do nothing and connection to linksys is not working). Linksys speed is not problem for me.
But what is happening to master port is that master port is automaticaly set to 10Mbit halfduplex too. And this is causing my internet connection problems. Speed is set for all switching port to 10Mbit 
Between master port (eth3) and wan port I have routing to internet. But the speed is dramatic. How to prevent this switching master port to the slowest port speed?
I did not find anything what can help. At this moment I created bridge and add eth3, eth4, eth5 to this bridge. It is working, but I am not sure if this is the good solution. Any help or explanation will be very appreciated.
Thank you all.