We have been upgrading our infrastructure over several years and utilizing Cisco switching in addition to our routers already in place. Sometimes but not always we experience ports becoming disabled periodocally. I know when manufactured that the ports are programmed to auto-negotiate. I have no authority to but I am doing the best I can to gain access to programming our switches where needed to full-duplex mode. I also realize other factors which may play a role in the ports being disabled but my troubleshooting skills are superior. Having eliminated all other possibilities of ports down state would the full-duplex mode solve the problems? One other issue involved here and researching many avenues is that we have MAC based computers on the network. We also have problems with our wireless access points when changed over to Cisco switching which we never had using 3COM. Any information generated here which may be helpful would be greatly appreciated and would be rated.