This Network Update was distributed via the Exchange Network email alerts list on February 17, 2006.

The Network Operations Board has issued a decision memorandum approving a new namespace strategy for the Exchange Network. Previous Exchange Network (EN) standards called for the use of URN-formatted namespaces in EN XML schema and instance files. The current EN XML Registry confirms that several naming conventions for network namespaces are currently in use. As schemas and their tags continue to proliferate, the consistent use of namespaces on the EN will become increasingly more important. The goals of implementing a namespace strategy for the Exchange Network are to bring predictability to developers and users and to resolve known points of confusion and implementation problems.

You can find the full text of the NOB decision memorandum at http://www.exchangenetwork.net/operations/nob/decisions.htm. You can download a copy of the full guidance document entitled Namespace Organization, Naming, and Schema File Location from the Schema Development section of the website at http://www.exchangenetwork.net/dev_schema/index.htm

Please note that this decision does NOT affect existing schema. Current versions of existing schema will be “grandfathered” using their existing namespace declarations. All future schema development should change namespaces at the next major version iteration. Instance files should follow conventions relevant to the schema they are using.

The following summarizes the NOB's recommendations which are embodied in the document entitled Namespace Organization, Naming and Schema File Location.

Recommendation 1: Namespaces on the EN will be URL formatted following the specifications
outlined in Section 4.1.2, Namespace Construction.

Recommendation 2: Version information is required in all EN namespaces. Accordingly,
versioning of schema themselves must be strictly enforced.

Recommendation 3: When declaring EN namespaces in instance files, the use of the
xsi:schemaLocation is optional. This tag can serve a subsidiary function for specifying schema against which instances can be validated.

For additional information on the Namespace strategy, please contact one of the following:

Connie Dwyer, EPA OEI, dwyer.connie@epa.gov
Scott Totten, Missouri Department of Natural Resources, scott.totten@dnr.mo.gov

Decision memoranda are official network policies that formally document all NOB decisions and describe who is affected and what actions are expected. With each of its decisions, the NOB strives to grow a more homogenous network without imposing undue burden on network partners.