Unable to establish link between PCS and PHY in SGMII mode

thank you very much for your quick reply. Finally it seems I got it working altough I had another issue. In my original design I didn't add an altgx_reconfig block because I thought I don't need to. This obviously was big mistake. In the example design they implemented this IP and so did I .... after 2 days of trying! Now I can send a package and capture it with wireshark. However, I still don't have a clue what this block actually does. But hopefully google will help me ....