DoD is proposing to amend the Defense Federal Acquisition Regulation Supplement to implement section 1656 of the National Defense Authorization Act for Fiscal Year 2018.  Section 1656 provides that DoD may not procure or obtain or extend or renew a contract to provide or obtain any equipment, system, or service to carry out the DoD nuclear deterrence mission or the DoD homeland defense mission that uses covered telecommunications equipment or services as a substantial or essential component of any system or as a critical technology as a part of any system.