Keep the ADR data rate index value between min and max values

CHANGELOG.md

@@ -27,6 +27,10 @@ For details about compatibility between different releases, see the **Commitment
 
 - Parsers for newly added normalized payload fields.
 
+### Fixed
+
+- ADR respects the MAC settings `adr.mode.dynamic.min-data-rate-index` and `adr.mode.dynamic.max-data-rate-index` values
+
 ## [3.34.2] - 2025-07-24
 
 ### Added

pkg/networkserver/mac/adr.go

@@ -583,6 +583,9 @@ func adrAdaptDataRate(
 ) float32 {
 	currentParameters, desiredParameters := macState.CurrentParameters, macState.DesiredParameters
 	currentDataRateIndex := currentParameters.AdrDataRateIndex
+	// Keep the data rate index between min and max
+	currentDataRateIndex = max(currentDataRateIndex, minDataRateIndex)
+	currentDataRateIndex = min(currentDataRateIndex, maxDataRateIndex)
 	// NOTE: Network Server may only increase the data rate index of the device.
 	if currentDataRateIndex > minDataRateIndex {
 		minDataRateIndex = currentDataRateIndex

pkg/networkserver/mac/adr_test.go

@@ -2185,8 +2185,69 @@ func TestADRAdaptDataRate(t *testing.T) {
 			},
 			OutputMargin: 5.0,
 		},
+		{
+			Name: "current index below min value",
+
+			MACState: &ttnpb.MACState{
+				CurrentParameters: &ttnpb.MACParameters{
+					AdrDataRateIndex: ttnpb.DataRateIndex_DATA_RATE_0,
+					AdrTxPowerIndex:  1,
+				},
+				DesiredParameters: &ttnpb.MACParameters{
+					AdrDataRateIndex: ttnpb.DataRateIndex_DATA_RATE_0,
+					AdrTxPowerIndex:  1,
+				},
+			},
+			Band:                   &band.EU_863_870_RP1_V1_0_3_Rev_A,
+			MinDataRateIndex:       ttnpb.DataRateIndex_DATA_RATE_2,
+			MaxDataRateIndex:       ttnpb.DataRateIndex_DATA_RATE_3,
+			AllowedDataRateIndices: newDataRateIndexRange(ttnpb.DataRateIndex_DATA_RATE_0, ttnpb.DataRateIndex_DATA_RATE_5),
+			InitialMargin:          0,
+
+			OutputMACState: &ttnpb.MACState{
+				CurrentParameters: &ttnpb.MACParameters{
+					AdrDataRateIndex: ttnpb.DataRateIndex_DATA_RATE_0,
+					AdrTxPowerIndex:  1,
+				},
+				DesiredParameters: &ttnpb.MACParameters{
+					AdrDataRateIndex: ttnpb.DataRateIndex_DATA_RATE_2,
+					AdrTxPowerIndex:  1,
+				},
+			},
+			OutputMargin: 0,
+		},
+		{
+			Name: "current index above max value",
+
+			MACState: &ttnpb.MACState{
+				CurrentParameters: &ttnpb.MACParameters{
+					AdrDataRateIndex: ttnpb.DataRateIndex_DATA_RATE_5,
+					AdrTxPowerIndex:  1,
+				},
+				DesiredParameters: &ttnpb.MACParameters{
+					AdrDataRateIndex: ttnpb.DataRateIndex_DATA_RATE_5,
+					AdrTxPowerIndex:  1,
+				},
+			},
+			Band:                   &band.EU_863_870_RP1_V1_0_3_Rev_A,
+			MinDataRateIndex:       ttnpb.DataRateIndex_DATA_RATE_2,
+			MaxDataRateIndex:       ttnpb.DataRateIndex_DATA_RATE_3,
+			AllowedDataRateIndices: newDataRateIndexRange(ttnpb.DataRateIndex_DATA_RATE_0, ttnpb.DataRateIndex_DATA_RATE_5),
+			InitialMargin:          0,
+
+			OutputMACState: &ttnpb.MACState{
+				CurrentParameters: &ttnpb.MACParameters{
+					AdrDataRateIndex: ttnpb.DataRateIndex_DATA_RATE_5,
+					AdrTxPowerIndex:  1,
+				},
+				DesiredParameters: &ttnpb.MACParameters{
+					AdrDataRateIndex: ttnpb.DataRateIndex_DATA_RATE_3,
+					AdrTxPowerIndex:  1,
+				},
+			},
+			OutputMargin: 0,
+		},
 	} {
-		tc := tc
 		t.Run(tc.Name, func(t *testing.T) {
 			t.Parallel()