A protein complex that is found in the endoplasmic reticulum membrane of eukaryotes and transfers lipid-linked oligosaccharide precursor to asparagine residues on nascent proteins. In yeast, the complex includes at least nine different subunits, whereas in mammalian cells at least three different forms of the complex have been detected. [ http://www.ncbi.nlm.nih.gov/pubmed/15835887 https://www.worldcat.org/search?q=bn%3A0879695595 ]