I've DE2-115 board, Cyclone IV E. I want to test the Ethernet/ TSE by sending packets or frames. this board has two ethernet port so it might be work to send loopback like in "an633: Implementing Loopback in Triple-SpeedEthernet Designs With LVDS I/O and GX Transceivers". However, there is Packet generator & monitor ip cores for Cyclone IV. Is there any experiment or tutorial could help with this? The link below is a tutorial TSE by sending frames between the de2-115 ethernets. all the tutorial works well except the final stage after compilation there is Timequest problem. ftp://ftp.altera.com/up/pub/altera_material/12.0/tutorials/de2-115/ I'm sure there are some of you try to test the ethernet in loopback internal or external or another way may be. could you share with us what you did and also the difficulties. Thanks in advance to all of you.