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  <xsd:element id="rbbn_IPOpticalNetworksMember" abstract="true" name="IPOpticalNetworksMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" />
  <xsd:element id="rbbn_A2023RestructuringInitiativeMember" abstract="true" name="A2023RestructuringInitiativeMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" />
  <xsd:element id="rbbn_DebtInstrumentPeriodThreeMember" abstract="true" name="DebtInstrumentPeriodThreeMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" />
  <xsd:element id="rbbn_RestrictedStockRestrictedStockUnitsAndPerformanceStockUnitsMember" abstract="true" name="RestrictedStockRestrictedStockUnitsAndPerformanceStockUnitsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" />
  <xsd:element id="rbbn_ProductCostOfSalesMember" abstract="true" name="ProductCostOfSalesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" />
  <xsd:element id="rbbn_NumberOfPrimaryRevenueSources" abstract="false" name="NumberOfPrimaryRevenueSources" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:integerItemType" />
  <xsd:element id="rbbn_IncreaseDecreaseInContractWithCustomerLiabilityCurrentNet" abstract="false" name="IncreaseDecreaseInContractWithCustomerLiabilityCurrentNet" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" />
  <xsd:element id="rbbn_OperatingLeaseCostAcceleratedAmortization" abstract="false" name="OperatingLeaseCostAcceleratedAmortization" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" />
  <xsd:element id="rbbn_VariableAndOtherFacilitiesCostsMember" abstract="true" name="VariableAndOtherFacilitiesCostsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" />
  <xsd:element id="rbbn_SegmentAdjustedGrossProfit" abstract="false" name="SegmentAdjustedGrossProfit" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" />
  <xsd:element id="rbbn_AmortizationOfAcquiredTechnology" abstract="false" name="AmortizationOfAcquiredTechnology" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" />
  <xsd:element id="rbbn_CharterComplaintsMember" abstract="true" name="CharterComplaintsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" />
  <xsd:element id="rbbn_WarrantLiabilityNoncurrent" abstract="false" name="WarrantLiabilityNoncurrent" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" />
  <xsd:element id="rbbn_ShareBasedCompensationArrangementByShareBasedPaymentAwardPercentOfGranted" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardPercentOfGranted" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType" />
  <xsd:element id="rbbn_ServiceCostOfSalesMember" abstract="true" name="ServiceCostOfSalesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" />
  <xsd:element id="rbbn_PreferredStockConversionBasisRedemptionRate" abstract="false" name="PreferredStockConversionBasisRedemptionRate" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types:percentItemType" />
  <xsd:element id="rbbn_PerformanceSharesMarketBasedMember" abstract="true" name="PerformanceSharesMarketBasedMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" />
  <xsd:element id="rbbn_ServiceRevenueMaintenanceMember" abstract="true" name="ServiceRevenueMaintenanceMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" />
  <xsd:element id="rbbn_DebtInstrumentPeriodAxis" abstract="true" name="DebtInstrumentPeriodAxis" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:dimensionItem" type="xbrli:stringItemType" />
  <xsd:element id="rbbn_ScheduleOfFairValueOfPreferredStockAndWarrantsTableTextBlock" abstract="false" name="ScheduleOfFairValueOfPreferredStockAndWarrantsTableTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:textBlockItemType" />
  <xsd:element id="rbbn_PreferredStockLiabilityChangeInFairValue" abstract="false" name="PreferredStockLiabilityChangeInFairValue" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" />
  <xsd:element id="rbbn_DepreciationAndAmortizationOfTangibleAssets" abstract="false" name="DepreciationAndAmortizationOfTangibleAssets" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" />
  <xsd:element id="rbbn_PerformanceSharesPerformanceBasedMember" abstract="true" name="PerformanceSharesPerformanceBasedMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" />
  <xsd:element id="rbbn_A2024CreditAgreementMember" abstract="true" name="A2024CreditAgreementMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" />
  <xsd:element id="rbbn_TermLoanMember" abstract="true" name="TermLoanMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" />
  <xsd:element id="rbbn_DebtInstrumentPeriodDomain" abstract="true" name="DebtInstrumentPeriodDomain" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" />
  <xsd:element id="rbbn_PreferredStockLiabilityCallPremium" abstract="false" name="PreferredStockLiabilityCallPremium" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" />
  <xsd:element id="rbbn_CloudAndEdgeMember" abstract="true" name="CloudAndEdgeMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" />
  <xsd:element id="rbbn_LeasesWeightedAverageDiscountRateAbstract" abstract="true" name="LeasesWeightedAverageDiscountRateAbstract" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType" />
  <xsd:element id="rbbn_ResearchAndDevelopmentGrantRoyaltyRate" abstract="false" name="ResearchAndDevelopmentGrantRoyaltyRate" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types:percentItemType" />
  <xsd:element id="rbbn_PreferredStockRedemptionPremiumPercentageYearOne" abstract="false" name="PreferredStockRedemptionPremiumPercentageYearOne" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType" />
  <xsd:element id="rbbn_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfPerformancePeriods" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfPerformancePeriods" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:integerItemType" />
  <xsd:element id="rbbn_VariousUncommittedFacilitiesMember" abstract="true" name="VariousUncommittedFacilitiesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" />
  <xsd:element id="rbbn_CharterComplaintFiledWithSupremeCourtOfTheStateOfNewYorkMember" abstract="true" name="CharterComplaintFiledWithSupremeCourtOfTheStateOfNewYorkMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" />
  <xsd:element id="rbbn_RestrictedStockAndRestrictedStockUnitsMember" abstract="true" name="RestrictedStockAndRestrictedStockUnitsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" />
  <xsd:element id="rbbn_TermLoanFacilityMember" abstract="true" name="TermLoanFacilityMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" />
  <xsd:element id="rbbn_PaymentOfFactoringFees" abstract="false" name="PaymentOfFactoringFees" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" />
  <xsd:element id="rbbn_ServiceRevenueProfessionalServicesMember" abstract="true" name="ServiceRevenueProfessionalServicesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" />
  <xsd:element id="rbbn_IncreaseDecreaseInContractWithCustomerLiabilityNoncurrentNet" abstract="false" name="IncreaseDecreaseInContractWithCustomerLiabilityNoncurrentNet" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" />
  <xsd:element id="rbbn_DerivativeNotionalAmountSold" abstract="false" name="DerivativeNotionalAmountSold" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" />
  <xsd:element id="rbbn_AssetsAndLiabilitiesLesseeTableTextBlock" abstract="false" name="AssetsAndLiabilitiesLesseeTableTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:textBlockItemType" />
  <xsd:element id="rbbn_PreferredStockRedemptionPremiumPercentageYearTwo" abstract="false" name="PreferredStockRedemptionPremiumPercentageYearTwo" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType" />
  <xsd:element id="rbbn_WeightedAverageRemainingLeaseTermAbstract" abstract="true" name="WeightedAverageRemainingLeaseTermAbstract" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType" />
  <xsd:element id="rbbn_InventoryFinishedGoodsAndDeferredCostOfGoodsSold" abstract="false" name="InventoryFinishedGoodsAndDeferredCostOfGoodsSold" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" />
  <xsd:element id="rbbn_BlackScholesPricingModelMember" abstract="true" name="BlackScholesPricingModelMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" />
  <xsd:element id="rbbn_OtherGeographicalLocationMember" abstract="true" name="OtherGeographicalLocationMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" />
  <xsd:element id="rbbn_AmortizationOfDerivativeInstrument" abstract="false" name="AmortizationOfDerivativeInstrument" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" />
  <xsd:element id="rbbn_VerizonCommunicationsIncMember" abstract="true" name="VerizonCommunicationsIncMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" />
  <xsd:element id="rbbn_AmortizationOfAcquiredIntangibleAssets" abstract="false" name="AmortizationOfAcquiredIntangibleAssets" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" />
  <xsd:element id="rbbn_ResearchAndDevelopmentGrantPercentThresholdOfGrants" abstract="false" name="ResearchAndDevelopmentGrantPercentThresholdOfGrants" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types:percentItemType" />
  <xsd:element id="rbbn_IncreaseDecreaseInAccountsReceivableCurrent" abstract="false" name="IncreaseDecreaseInAccountsReceivableCurrent" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" />
  <xsd:element id="rbbn_VariableLeaseCostAccrued" abstract="false" name="VariableLeaseCostAccrued" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" />
  <xsd:element id="rbbn_A2022RestructuringInitiativeMember" abstract="true" name="A2022RestructuringInitiativeMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" />
  <xsd:element id="rbbn_RevenueFromContractWithCustomerCustomerSupportAgreementTerm" abstract="false" name="RevenueFromContractWithCustomerCustomerSupportAgreementTerm" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType" />
  <xsd:element id="rbbn_PreferredStockLiabilityRedemptionAmount" abstract="false" name="PreferredStockLiabilityRedemptionAmount" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" />
  <xsd:element name="PreferredStockDividendRateForFirstYearPercentage" id="rbbn_PreferredStockDividendRateForFirstYearPercentage" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="PreferredStockDividendRateForSecondYearPercentage" id="rbbn_PreferredStockDividendRateForSecondYearPercentage" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="PreferredStockDividendRateForThereafterPercentage" id="rbbn_PreferredStockDividendRateForThereafterPercentage" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="Rule10b51ArrangementModifiedFlag" id="rbbn_Rule10b51ArrangementModifiedFlag" type="xbrli:booleanItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="NonRule10b51ArrangementModifiedFlag" id="rbbn_NonRule10b51ArrangementModifiedFlag" type="xbrli:booleanItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element id="rbbn_DebtInstrumentUnamortizedDebtIssuanceCostsContraLiability" abstract="false" name="DebtInstrumentUnamortizedDebtIssuanceCostsContraLiability" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" />
  <xsd:element name="AccruedLiabilitiesAndOtherLiabilitiesCurrent" id="rbbn_AccruedLiabilitiesAndOtherLiabilitiesCurrent" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="credit" />
  <xsd:element name="AmortizationOfAcquiredTechnologyMember" id="rbbn_AmortizationOfAcquiredTechnologyMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="PreferredStockRedemptionCallPremiumPercentage" id="rbbn_PreferredStockRedemptionCallPremiumPercentage" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="AlternateBaseRateMember" id="rbbn_AlternateBaseRateMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="DebtInstrumentRemainingPrincipalPayableAtMaturity" id="rbbn_DebtInstrumentRemainingPrincipalPayableAtMaturity" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="debit" />
  <xsd:element name="RevenueRecognitionDurationOfTrainingService" id="rbbn_RevenueRecognitionDurationOfTrainingService" type="xbrli:durationItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="ContractWithCustomerPaymentsTerm" id="rbbn_ContractWithCustomerPaymentsTerm" type="xbrli:durationItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="RedeemedPreferredStockWithPortionOfProceeds" id="rbbn_RedeemedPreferredStockWithPortionOfProceeds" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="debit" />
  <xsd:element name="RevenueRemainingPerformanceObligationUnrecognized" id="rbbn_RevenueRemainingPerformanceObligationUnrecognized" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="credit" />
  <xsd:element name="A2025RestructuringInitiativeMember" id="rbbn_A2025RestructuringInitiativeMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="StockIssuedDuringPeriodValueWarrantsExercised" id="rbbn_StockIssuedDuringPeriodValueWarrantsExercised" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="credit" />
  <xsd:element name="ClassOfWarrantOrRightNumberOfWarrantsExercised" id="rbbn_ClassOfWarrantOrRightNumberOfWarrantsExercised" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="StockIssuedDuringPeriodSharesWarrantsExercised" id="rbbn_StockIssuedDuringPeriodSharesWarrantsExercised" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="StockIssuedDuringPeriodWarrantsExercisedWeightedAverageFairValueOfShares" id="rbbn_StockIssuedDuringPeriodWarrantsExercisedWeightedAverageFairValueOfShares" type="dtr-types:perShareItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="NonCashActivityOfWarrantLiabilityReleasedToAdditionalPaidInCapital" id="rbbn_NonCashActivityOfWarrantLiabilityReleasedToAdditionalPaidInCapital" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="credit" />
  <xsd:element name="AccruedLiabilitiesAndOtherLiabilitiesCurrentMember" id="rbbn_AccruedLiabilitiesAndOtherLiabilitiesCurrentMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="PaymentOfPreferredStockDividendsLiabilityCumulativeDividends" id="rbbn_PaymentOfPreferredStockDividendsLiabilityCumulativeDividends" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="credit" />
  <xsd:element name="CommonStockIncreaseInSharesAuthorized" id="rbbn_CommonStockIncreaseInSharesAuthorized" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="CommonStockRepurchasesTextBlock" id="rbbn_CommonStockRepurchasesTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="MeasurementInputFairValueOfWarrantPerShareMember" id="rbbn_MeasurementInputFairValueOfWarrantPerShareMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="IncentiveAwardPlan2025Member" id="rbbn_IncentiveAwardPlan2025Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="ShareBasedCompensationArrangementByShareBasedPaymentAwardMaximumSharesAuthorizedExcludingSharesReservedUnderPreviousPlan" id="rbbn_ShareBasedCompensationArrangementByShareBasedPaymentAwardMaximumSharesAuthorizedExcludingSharesReservedUnderPreviousPlan" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="ShareBasedCompensationArrangementByShareBasedPaymentAwardAuthorizedSharesReservedUnderPreviousPlan" id="rbbn_ShareBasedCompensationArrangementByShareBasedPaymentAwardAuthorizedSharesReservedUnderPreviousPlan" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="BhartiTelecomLimitedMember" id="rbbn_BhartiTelecomLimitedMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
</xsd:schema>
