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  <xs:element id="rbbn_LesseeOperatingLeaseLiabilityToBePaidAfterYearFour" abstract="false" name="LesseeOperatingLeaseLiabilityToBePaidAfterYearFour" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="rbbn_DebtInstrumentPeriodFourMember" abstract="true" name="DebtInstrumentPeriodFourMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="rbbn_TermLoanFacilityTermALoanMember" abstract="true" name="TermLoanFacilityTermALoanMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="rbbn_AmortizationOfAcquiredTechnology" abstract="false" name="AmortizationOfAcquiredTechnology" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="rbbn_TermLoanFacilityMember" abstract="true" name="TermLoanFacilityMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="rbbn_PerformanceSharesMarketBasedMember" abstract="true" name="PerformanceSharesMarketBasedMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="rbbn_A2020CreditAgreementMember" abstract="true" name="A2020CreditAgreementMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="rbbn_AVCTInvestmentMember" abstract="true" name="AVCTInvestmentMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="rbbn_DebtInstrumentPeriodAxis" abstract="true" name="DebtInstrumentPeriodAxis" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:dimensionItem" type="xbrli:stringItemType"/>
  <xs:element id="rbbn_ProceedsFromStockOptionsExercisedGross" abstract="false" name="ProceedsFromStockOptionsExercisedGross" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="rbbn_ContractWithCustomerChangeInLiabilityCurrentRollForward" abstract="true" name="ContractWithCustomerChangeInLiabilityCurrentRollForward" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="rbbn_DebtInstrumentPeriodTwoMember" abstract="true" name="DebtInstrumentPeriodTwoMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="rbbn_VariableAndOtherFacilitiesCostsMember" abstract="true" name="VariableAndOtherFacilitiesCostsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="rbbn_ServiceRevenueMaintenanceMember" abstract="true" name="ServiceRevenueMaintenanceMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="rbbn_ResearchAndDevelopmentGrantMaximumFutureRoyaltyCommitments" abstract="false" name="ResearchAndDevelopmentGrantMaximumFutureRoyaltyCommitments" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="rbbn_PaymentOfFactoringFees" abstract="false" name="PaymentOfFactoringFees" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="rbbn_AmortizationOfAcquiredIntangibleAssets" abstract="false" name="AmortizationOfAcquiredIntangibleAssets" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="rbbn_DebtInstrumentPeriodFiveMember" abstract="true" name="DebtInstrumentPeriodFiveMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="rbbn_LineOfCreditFacilityAccordionFeatureIncreaseLimit" abstract="false" name="LineOfCreditFacilityAccordionFeatureIncreaseLimit" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="rbbn_LeaseLiabilityNoncurrentAbstract" abstract="true" name="LeaseLiabilityNoncurrentAbstract" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="rbbn_DebtInstrumentPeriodOneMember" abstract="true" name="DebtInstrumentPeriodOneMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="rbbn_ServiceProviderCustomersMember" abstract="true" name="ServiceProviderCustomersMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="rbbn_ServiceCostOfSalesMember" abstract="true" name="ServiceCostOfSalesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="rbbn_AtAndTIncMember" abstract="true" name="AtAndTIncMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="rbbn_LeaseLiabilityCurrentAbstract" abstract="true" name="LeaseLiabilityCurrentAbstract" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="rbbn_VerizonCommunicationsIncMember" abstract="true" name="VerizonCommunicationsIncMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="rbbn_RevenueFromContractWithCustomerCustomerSupportAgreementTerm" abstract="false" name="RevenueFromContractWithCustomerCustomerSupportAgreementTerm" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="rbbn_ContractWithCustomerChangeInAssetUnbilledReceivablesCurrentRollForward" abstract="true" name="ContractWithCustomerChangeInAssetUnbilledReceivablesCurrentRollForward" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="rbbn_DebtInstrumentPremiumFromVoluntaryRepaymentPercentage" abstract="false" name="DebtInstrumentPremiumFromVoluntaryRepaymentPercentage" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="rbbn_VariableLeaseCostAccrued" abstract="false" name="VariableLeaseCostAccrued" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="rbbn_AmortizationOfDerivativeInstrument" abstract="false" name="AmortizationOfDerivativeInstrument" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="rbbn_ShareBasedCompensationArrangementByShareBasedPaymentAwardPercentOfPerformanceMetricsAchieved" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardPercentOfPerformanceMetricsAchieved" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="rbbn_LineOfCreditFacilityNetLeverageRatio" abstract="false" name="LineOfCreditFacilityNetLeverageRatio" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="rbbn_LongTermDebtMaturityFinalPayment" abstract="false" name="LongTermDebtMaturityFinalPayment" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="rbbn_ResearchAndDevelopmentGrantPercentThresholdOfGrants" abstract="false" name="ResearchAndDevelopmentGrantPercentThresholdOfGrants" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="rbbn_CloudAndEdgeMember" abstract="true" name="CloudAndEdgeMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="rbbn_LineOfCreditFacilityAccordionFeaturePercentOfAggregateAmountAppliedForRepayment" abstract="false" name="LineOfCreditFacilityAccordionFeaturePercentOfAggregateAmountAppliedForRepayment" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="rbbn_RestrictedStockAndRestrictedStockUnitsMember" abstract="true" name="RestrictedStockAndRestrictedStockUnitsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="rbbn_ShareBasedCompensationArrangementByShareBasedPaymentAwardPercentOfGranted" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardPercentOfGranted" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="rbbn_ContractWithCustomerChangeInLiabilityNoncurrentRollForward" abstract="true" name="ContractWithCustomerChangeInLiabilityNoncurrentRollForward" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="rbbn_A2022RestructuringInitiativeMember" abstract="true" name="A2022RestructuringInitiativeMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="rbbn_ShareBasedPaymentArrangementOptionsRestrictedAndPerformanceBasedStockMember" abstract="true" name="ShareBasedPaymentArrangementOptionsRestrictedAndPerformanceBasedStockMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="rbbn_OneCustomerMember" abstract="true" name="OneCustomerMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="rbbn_WeightedAverageRemainingLeaseTermAbstract" abstract="true" name="WeightedAverageRemainingLeaseTermAbstract" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="rbbn_LeaseLiability" abstract="false" name="LeaseLiability" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
</xs:schema>
