Understanding Gcc High Gcc Dod And Commercial Microsoft 365

Understanding GCC, GCC High, and GCC DoD — Microsoft 365 Government Cloud

Microsoft 365 GCC, GCC High, and GCC DoD are three separate government cloud environments with different compliance levels. GCC covers FedRAMP Moderate and CJIS. GCC High covers FedRAMP High and CMMC Level 2/3 for Controlled Unclassified Information. GCC DoD is for Department of Defense IL4/IL5 workloads. Commercial M365 does not meet most government requirements.

GCC vs GCC High vs GCC DoD — Comparison Table

Criterion	M365 Commercial	M365 GCC	M365 GCC High	M365 GCC DoD
FedRAMP level	None	Moderate	High	High (DoD SRG)
CMMC support	No	Limited	Level 2 and 3 (CUI)	Level 3 (CUI)
ITAR/EAR eligible	No	No	Yes	Yes
Data residency	Global (multi-region)	U.S. only	U.S. only (screened personnel)	U.S. DoD data centers
Staff screening	No government screening	U.S. citizens only	U.S. citizens, screened by Microsoft	U.S. citizens, DoD-screened
Who needs it	Commercial organizations	State/local/federal agencies; CJIS	Defense contractors handling CUI	DoD agencies only
Feature parity with commercial M365	Full	~90%	~80%	~75%

Key facts

• GCC High is required for defense contractors handling CUI under CMMC Level 2 (110 NIST 800-171 controls) or Level 3 (134 controls).
• GCC High migration timeline: 12–24 weeks including tenant provisioning, identity configuration, data migration, and user transition.
• Commercial Microsoft 365 personnel are not screened to government standards — disqualifying it for most government compliance scenarios.
• EPC Group has performed GCC and GCC High migrations for federal agencies and defense contractors.
• EPC Group holds core Microsoft Solutions Partner designations and is a FedRAMP framework contributor.

Microsoft 365 GCC — What You Need to Know

GCC (Government Community Cloud) is the entry-level government Microsoft 365 environment. It meets FedRAMP Moderate requirements.

• Who needs GCC — U.S. federal, state, local, tribal, and territorial government agencies. Also eligible: contractors with government contracts that don't involve CUI.
• Compliance certifications — FedRAMP Moderate, CJIS, IRS 1075, HIPAA, ITAR (limited).
• Data residency — All data stored in U.S.-based Azure Government data centers.
• Staff screening — Microsoft personnel supporting GCC are U.S. citizens only.
• Feature gaps — Some commercial M365 features (certain Teams integrations, third-party apps) are not available in GCC.

Microsoft 365 GCC High — What You Need to Know

GCC High is the environment for organizations handling Controlled Unclassified Information (CUI) under CMMC compliance requirements.

• Who needs GCC High — Defense contractors handling CUI. Organizations pursuing CMMC Level 2 or Level 3 certification.
• Compliance certifications — FedRAMP High, CMMC Level 2 (110 controls), CMMC Level 3 (134 controls), ITAR, DoD IL2/IL4.
• Staff screening — Microsoft personnel supporting GCC High are U.S. citizens with background screening.
• ITAR eligibility — GCC High is ITAR-eligible for controlled technical data. GCC and Commercial are not.
• Feature gaps — Approximately 20% of commercial M365 features are not available. Some third-party integrations are unavailable.

Microsoft 365 GCC DoD — What You Need to Know

GCC DoD is an isolated environment exclusively for Department of Defense agencies and authorized contractors.

• Who needs GCC DoD — DoD agencies only. Not available to commercial or non-DoD government entities.
• Compliance level — DoD Security Requirements Guide (SRG) IL4 and IL5.
• Physical isolation — Hosted in dedicated DoD-specific Azure Government data centers.
• Feature gaps — Approximately 25% of commercial M365 features unavailable. Strictest feature restrictions of the three environments.

GCC High Migration Process

Migrating from commercial Microsoft 365 to GCC High requires a full tenant-to-tenant migration. This is a major project — not a configuration change.

• Tenant provisioning — 2–4 weeks. New GCC High tenant created with government-eligible subscription.
• Identity and DNS configuration — 2–4 weeks. Azure AD/Entra ID sync, UPN alignment, domain federation.
• Pilot migration — 2–4 weeks. 10–15% of users migrated and validated.
• Full data migration — 4–12 weeks. Exchange Online, SharePoint, OneDrive, Teams migrated in waves.
• User transition and validation — 2–4 weeks. Cutover, helpdesk support, validation.
• Total timeline: 12–24 weeks depending on data volume and complexity.

CMMC and GCC High

GCC High provides the cloud infrastructure that supports CMMC Level 2 compliance. But GCC High alone does not make you CMMC-certified.

• CMMC certification also requires documented policies, procedures, staff training, and physical security controls.
• CMMC Level 2 requires 110 NIST 800-171 controls. Level 3 requires 134 controls.
• A Certified Third-Party Assessment Organization (C3PAO) must validate CMMC Level 2 for most contracts.
• EPC Group assists with both GCC High migration and CMMC control implementation.

Frequently asked questions

What is the difference between GCC and GCC High?

GCC covers FedRAMP Moderate for standard government agencies. GCC High covers FedRAMP High and CMMC for defense contractors handling Controlled Unclassified Information (CUI). GCC High has stricter staff screening and more feature restrictions than GCC.

Do I need GCC High for CMMC compliance?

Yes. CMMC Level 2 and Level 3 require GCC High infrastructure for Microsoft 365 workloads that store or process CUI. Commercial M365 cannot satisfy CMMC requirements for CUI handling.

How long does a GCC High migration take?

A GCC High migration takes 12–24 weeks. Tenant provisioning takes 2–4 weeks. Full data migration takes 4–12 weeks depending on volume. Total timeline depends on organization size and complexity.

What features are missing in GCC High vs commercial M365?

Approximately 20% of commercial M365 features are unavailable in GCC High. Most gaps are in third-party integrations and some Teams features. Core productivity features (Exchange, SharePoint, Teams, OneDrive) are available in GCC High.

Does EPC Group perform GCC High migrations?

Yes. EPC Group performs tenant-to-tenant migrations from commercial Microsoft 365 to GCC High. We handle identity migration, data migration, CMMC control configuration, and user transition. GCC High migration engagements start at $75,000.

Schedule a GCC High assessment

Talk to an EPC Group government cloud architect about your GCC High migration, CMMC readiness, or FedRAMP requirements. Call (888) 381-9725 or request a 30-minute discovery call.