# Boundary Object
A boundary object is an entity that participates in more than one interception stage or presents different identities at different technical boundaries.
## Examples in the stage model
- Intel ME/CSME with AMT spans silicon, protected firmware, network reachability, and enterprise management.
- A programmable USB device can present storage, keyboard, serial, and network identities.
- A virtual-machine firmware image is pre-OS firmware to the guest but ordinary host-side data to the hypervisor.
## Evidentiary consequence
A single-stage defense or observation may not intersect the component’s other authority surfaces. Record every stage the object occupies and identify where each item of evidence was collected.
## Source
[[Index - Stages of Interception#Cross-stage residents — the out-of-band management plane|Cross-stage residents]] · [[Stage Folding Under Virtualization]] · [[Translation Boundary]].