# Data center labeling glossary > Definitions used throughout the Rackstamp library. Canonical page: https://datacenterlabeling.com/glossary ## Identifier The exact value used to distinguish an object or location within a defined scope. ## Asset ID An organization's identifier for an asset. Keep its relationship to the manufacturer's serial number and current location explicit. ## Location ID An identifier for a place, such as a site, room, rack, or mounting position. ## Alias Another name used for the same object, such as the equipment name displayed in an alarm system. ## Endpoint The specific termination of a connection, including enough device, panel, and port context to identify it. ## Local and remote Labels describing the two ends from a stated viewpoint. Keep that viewpoint consistent in records and examples. ## Rack unit / RU / U The rack-position reference used by the equipment and the site's mounting convention. Record the face and occupied span as well as the position. ## Patch panel A termination panel whose ports connect cabling. A port number needs its panel context. ## Breakout A cable or connection arrangement that separates a higher-count connection into identified legs or ports. Use the actual assembly's mapping. ## PDU Power distribution unit. Outlet identity is a separate field from the PDU's own identity. ## PSU Power supply unit. Use the inlet or PSU marking on the specific device. ## A/B feed designation A site's label for power paths. The designation and any color legend must be tied to its documented design. ## CDU Coolant distribution unit. Preserve the installed manufacturer's names for its connections and components. ## BMS Building management system. An alarm name may need a cross-reference to the physical equipment identifier. ## DCIM Data center infrastructure management. In these guides, the system used to hold relevant equipment, location, or connection records. ## CMDB Configuration management database. A source of configuration-item records and their relationships. ## Demarcation The defined handoff point between parties or systems. Record the physical endpoint and the responsibility boundary. ## LOA Letter of authorization. In a cross-connect workflow, use the provider's authorized connection details and process. ## MAC work Moves, additions, and changes. Here the term refers to infrastructure work, rather than a network interface address. ## Record owner The person or team responsible for maintaining and resolving a particular record or field. ## Verification evidence The observation, document, test-result reference, or approved record used to support a specific conclusion. ## Exception An unresolved discrepancy or a documented departure requiring an identified owner and disposition. ## Revision The version of a policy, drawing, worksheet, or source used for a task. ## Label proof An actual-size printed sample checked before issuing the full label batch. ## Quiet zone Blank space required around a machine-readable symbol. Use the requirements for the chosen symbol and printing application. ## AIM Automated infrastructure management. Systems that detect supported physical connectivity events and relate them to managed records; coverage depends on the installed hardware and integration. ## RFID Radio-frequency identification. A reader obtains an identifier from a compatible tag; an observation still needs interpretation and association with the correct asset. ## On-metal RFID tag A tag designed for operation on specified metallic mounting surfaces. Verify the actual mounting and reading environment in the pilot. ## As-built record A record of the installed arrangement at a stated revision. Compare it with later changes before assuming it remains current. ## Color legend A versioned mapping between a color and its intended meaning in a stated scope. Add readable text so color is not the only identifier. ## Port pitch Spacing between defined corresponding points on adjacent ports, commonly their centers. State the datum and units used. ## Group clearance A label-layout parameter for spacing between port groups. Its software definition must be reconciled with the physical measurement. ## Thermal transfer Printing that uses heat to transfer a marking material from a ribbon to the selected media. Media, ribbon, and settings must be compatible. ## Direct thermal Printing on a heat-sensitive medium without a separate transfer ribbon. Suitability depends on the specific material and exposure. ## Half-cut A cutting operation that leaves the backing connected while separating label material; available behavior depends on the printer and stock. ## Ghost asset A discrepancy in which a physical object and its expected inventory state do not agree, such as retired equipment that remains installed. Record the specific discrepancy. ## Namespace The defined scope in which an identifier is expected to be unique. A shortened value can need additional site or room context. ## Print batch A controlled group of label outputs tied to a data revision, template, and production setup. ## Acceptance criterion An observable condition used to decide whether a stated deliverable or work scope has been completed. ## False positive read A detection interpreted as a target observation when it should not have been included, such as an RFID read from a neighboring rack. ## False negative read A target expected in the observed scope that the reading process fails to detect. ## Label lifecycle cost The cost of producing, applying, maintaining, replacing, and reconciling labels over a defined period and scope.