The conversion of N-linked glycan (N = nitrogen) structures from the initially transferred oligosaccharide to a mature form, by the actions of glycosidases and glycosyltransferases. The early processing steps are conserved and play roles in glycoprotein folding and trafficking. [ http://www.ncbi.nlm.nih.gov/pubmed/12736198 https://www.worldcat.org/search?q=bn%3A0879695595 ]