Peoples. I thought I would point out the master.xml on github is invalid NML and will not parse using the nmlbase.xml and nsi-ext.xsd schemas as defined. The nsi:isReference attribute is not defined in schema, and therefore, cannot be parsed by JAXB based off the nmlbase.xml and nsi-ext.xsd schemas. There are two problems with the XML as defined: 1. There is no anyAttribute defined in the context of the Topology element from nmlbase.xml so attributes from an external namespace cannot be included. 2. There is no isReference attribute defined in nsi-ext.xsd so it cannot be used. If we intend to use this mechanism for an extended period of time I would suggest we formalize the required schema changes as part of topology distribution version 1.0. I attached what I modified to get my implementation to work correctly. These are backward compatible changes in NML, which will allow an application compiled with the new schema to read old files, however, the reverse is not true. We should probably do an update to the standard schema once we agree on how Service Definitions get supported. John