Complex sentence: In 1995 he cofounded the Palo Alto Internet Exchange (PAIX), and after Metromedia Fiber Network (MFN) bought it in 1999 served as the chief technology officer to MFN/AboveNet and later as the president of PAIX.
Split into simpler sentences: In 1995 he cofounded the Palo Alto Internet Exchange (PAIX), and after Metromedia Fiber Network (MFN) bought it in 1999. AboveNet later aquired MNF and he served as the chief technology officer to AboveNet and later as the president of PAIX.