Model Authorities and Model Exchange Jay Britton Principal Architect

Model Exchange Business Goal Neighboring parties in an interconnect exchange models. Each party is the “modeling authority” only for its own territory. Each party will use other parties’ internal models to create their external model. To accomplish this, Each party exports its internal model to its neighbors and keeps it up to date. Each party imports each neighbor’s model and uses it to develop and update its external model. Proposed Goal: an external model can be updated within an hour of a change to a neighbor’s internal.

Initial CIM Model Exchange Concept CIM Exchange (full, partial, incremental) CIM import / export CIM import / export System B Import Model System A Import Model a Proprietary / Home grown Extract / Merge Tools Proprietary / Home grown Extract / Merge Tools b A Internal Model B’s Model of A System A Local Vendor Model System B Local Vendor Model A’s model of B B Internal Model System B EMS System A EMS

Making CIM Exchange a Complete Process MRIDs as permanent unique object identifiers. Decide who assigns identifiers to each object. Name registry manages naming differences. Model exchange uses consistent identifiers. Specify the modeling territories precisely within the model. Include security against changes submitted by unauthorized parties. Report updates with CIM incremental updates. If problems arise, it is easy to identify the source. Mark equivalents in the model. Import process can easily recognize whether an update requires a new reduction. On-line systems receive and test updates incrementally. If problems arise, it is easy to identify the source

Central Concept: Model Authority Sets (MAS) Notation: Nodes represent individual CIM objects. Branches represent relations between objects. Two MAS types: Regional (single authority) Boundary (bipartisan authority / single caretaker) Rules: Every CIM object is in one and only one MAS. Each MAS controls object MRIDs in its territory. No object in a regional set relates directly to any object in another regional set.

A little more detailed look at a boundary example.

A UCTE boundary example.

Use Case: Peer-to-Peer Full Model Exchange CIM Modeler CIM Modeler A Region A Region boundary boundary B Region B Region a A Region (reduced) B Region (reduced) b System A EMS System B EMS CIM import CIM import Proprietary Model B Proprietary Model A

Use Case: A to B Incremental Update CIM Modeler CIM Modeler a a A Region A Region boundary boundary B Region B Region A Region (reduced) B Region (reduced) If the change can be processed against the reduced region, then it can be transferred directly to the CIM import for system B. System A Local Vendor System B Local Vendor CIM delta CIM MAS CIM delta Proprietary Model B Proprietary Model A

Use Case: Hierarchical Exchange CIM Upper Tier Modeling x A Region boundary B Region CIM Region Modeling CIM Region Modeling A Region A Region boundary boundary B Region B Region a b A Region (reduced) B Region (reduced) CIM import CIM import System A Local Vendor System B Local Vendor Proprietary Model A Proprietary Model B

Why is this a good thing? Generality MAS delineate all objects, not just the physical connection boundaries. Establishing authority and responsibility… Basis for efficient, repeatable processes. Clarifies responsibility for naming and MRIDs for all objects. Processing efficiency for model exchange: Merging regions is a simple union of objects. Extraction is a simple transfer of objects without modification. Replace simply extracts and discards before merging. Maximum XML file size can be limited to maximum largest MAS size, rather than whole interconnect. Checking that a change comes from the correct source. As a regional MA submitting a change: You can make any change you want to your regional set without fear that it would disturb a relationship from another region. Your changes can easily be validated because they must be referentially complete without any other regional set. If your change cannot comply with the above condition, it tells you immediately that you need to arbitrate a change in a boundary set. As the receiver checking the right to make a change: It must be referentially complete against the source’s region plus its boundaries.