In the GLUE Specification v. 2.0, page 8, it is specified the Entity class. In its "Association.End" there is just one field: "Extension.Key", but in the Extension class, its unique identifier is "LocalId". So in the Entity class, it should be specified "Extension.LocalId" instead of "Extension.Key". "Extension.Key" shouldn´t be used because of its description, which I quote here: "This identifier is not required to be unique; several instances of this class MAY hold the same value of this attribute". So this could be another erratum, isn´t it? Regards, David -- David Horat Software Engineer specialized in Grid and Web technologies IT Department – Grid Deployment Group CERN – European Organization for Nuclear Research » Where the web was born Phone +41 22 76 77996 http://davidhorat.com/ http://cern.ch/horat http://www.linkedin.com/in/davidhorat