CUI Enclave Architecture. On-Premise Alternative to GCC High.

It depends on your data type and your footprint. GCC High is mandatory for ITAR and export-controlled (EAR) data, and it fits organizations already all-in on Microsoft 365. An on-premise CUI enclave fits when you have a manufacturing or OT footprint, want to keep CUI off the cloud, need coverage for specialized and legacy assets that GCC High cannot reach, and want a faster, lower-friction path: it deploys in 3 to 6 weeks and covers roughly 87 of the 110 NIST SP 800-171 controls. Trout's Access Gate delivers the on-premise enclave, enforcing those controls at the network layer, including the OT and specialized assets GCC High cannot reach. Many contractors run both: GCC High for office productivity, Trout's on-premise enclave for the plant floor and specialized assets.

A CUI enclave is a logically separated environment within an organization's network that contains all systems and data subject to NIST SP 800-171 control requirements. The enclave is bounded by network controls, identity controls, and audit logging, only authorized users and processes can enter, and all traffic is recorded. The rest of the organization's IT environment can remain on commercial-grade infrastructure. The enclave approach is recognized in DoD CMMC guidance as a valid scope-reduction strategy: instead of treating the entire org as CUI-handling, you treat only the enclave that way.

GCC High is Microsoft's government-cloud tenant for Department of Defense contractors. It runs M365 (Exchange, Teams, SharePoint, OneDrive) in a dedicated infrastructure that meets DFARS 7012 and supports CUI workflows. It became the default CMMC path because it solves the email/collaboration side of CUI handling, but it forces the entire CUI user population into the GCC High tenant, with license, identity, and operational consequences that many small-to-mid contractors find prohibitive.

Four scenarios. (1) When your CUI flows include OT, PLCs, CNCs, or specialized assets that GCC High does not cover. (2) When most of your organization does not handle CUI, paying GCC High licenses for hundreds of non-CUI users is wasted budget. (3) When you operate disconnected or air-gapped sites that cannot maintain cloud connectivity. (4) When the migration cost and timeline to GCC High is incompatible with the contract deadline driving CMMC certification.

Yes, and for many large primes this is the practical answer. GCC High handles email, Teams, and collaboration for the CUI-handling user population. The on-premise enclave handles OT, specialized assets, and CUI flows that originate or terminate outside of M365 productivity tools. The two architectures coexist; the C3PAO assesses each scope against the relevant controls. This is increasingly the dominant architecture for primes with both modern IT and traditional manufacturing footprints.

Access Gate enforces 87 of the 110 controls directly at the network layer: access control (AC), audit and accountability (AU), identification and authentication (IA), system and communications protection (SC), system integrity (SI). The remaining ~23 controls require organizational measures (personnel security, physical, training) or customer-owned process controls. Every covered control generates auditor-ready evidence on demand, session logs, policy configurations, segmentation baselines, denied-access records.

3-6 weeks for a single-site enclave. Week 1: asset discovery and scope confirmation (which workflows, which users, which OT assets are in scope). Week 2: appliance installation and network integration, identity provider connection. Week 3: policy configuration, MFA enforcement, audit logging activation. Week 4: evidence package generation, SSP draft alignment, internal review. Weeks 5-6: remediation cycles and pre-C3PAO walkthrough. Compare to 9-18 months for a GCC High tenant migration with identity and data migration overhead.

GCC High is the safer default for ITAR and export-controlled EAR technical data, because it provides US-person-only access controls and a data-residency guarantee inside a DoD-authorized cloud boundary. An on-premise enclave can hold ITAR/EAR data as well, but the burden shifts to you: the enclave must enforce US-person access at the identity layer, keep the data physically on US soil under your control, and log every access for the export-control record. Access Gate binds every session to a named identity from your IdP and records it, which supplies the access-control and audit evidence an export-compliance program needs. Many contractors keep ITAR email and collaboration in GCC High and use the on-premise enclave for the ITAR-marked drawings that live on the shop floor and in the machine-tool workflow, where GCC High cannot reach.

Not directly, and it does not need to be. FedRAMP Moderate is an authorization framework for cloud service offerings; an on-premise enclave is not a cloud service, so FedRAMP does not apply to it. What a C3PAO actually assesses for CMMC Level 2 is whether the NIST SP 800-171 controls are met, and DFARS 252.204-7012 requires that any cloud service used to store or process CUI meet the FedRAMP Moderate baseline or equivalent. Keeping CUI inside an on-premise enclave keeps those flows out of the cloud entirely, so the FedRAMP-equivalence question narrows to only the specific cloud services you still use. This is a scope-reduction move, not a FedRAMP substitute.

Scope reduction works by drawing the CUI boundary as small as defensibly possible. Assets fall into categories the CMMC scoping guidance recognizes: CUI assets, Security Protection Assets, Contractor Risk Managed Assets, and Specialized Assets such as OT and IoT. Anything that does not store, process, or transmit CUI, and is separated from the CUI enclave by Access Gate enforcement, is out of the CUI assessment scope. In practice you place the engineering workstations, the machine tools that receive CUI drawings, and the CUI file share inside the enclave, and everything else stays on commercial M365 as out-of-scope. Fewer in-scope assets means fewer controls to prove and a smaller, cheaper, faster assessment.

You do not retire it, and you do not pretend it complies. Machine tools are Specialized Assets under the CMMC scoping guidance, and the recognized path is a compensating control documented as an enduring exception with a Plan of Action and Milestones (POA&M) entry in your System Security Plan. Access Gate is the compensating control: it sits in front of the control, enforces identity, allowlists the specific commands the workflow needs, denies the rest, and logs every session, so the asset that cannot itself do access control, audit, or identification gets those controls applied at its boundary. A CNC control cannot run an MFA client, so nothing is installed on it: Access Gate brokers the operator or vendor session and performs the MFA, and the controller never sees the authentication and is never modified.

Yes, and that is usually the first thing it removes. A VPN extends your network to a person; the enclave extends one authorized action to one asset and nothing else. A remote engineer or an OEM vendor authenticates through Access Gate, gets a time-bound session to exactly the one control or workstation the job requires, at the command level, and the session is recorded. There is no flat tunnel into the CUI segment and no standing vendor account waiting to be harvested.