diff --git a/core/api/src/main/java/org/onosproject/net/OmsPort.java b/core/api/src/main/java/org/onosproject/net/OmsPort.java
index f2065fd..5a3bb73 100644
--- a/core/api/src/main/java/org/onosproject/net/OmsPort.java
+++ b/core/api/src/main/java/org/onosproject/net/OmsPort.java
@@ -62,7 +62,7 @@
      */
     public short totalChannels() {
         Frequency diff = maxFrequency.subtract(minFrequency);
-        return (short) (diff.asHz() / (grid.asHz() + 1));
+        return (short) (diff.asHz() / grid.asHz());
     }
 
     /**
diff --git a/drivers/src/main/java/org/onosproject/driver/query/OFOpticalSwitch13LambdaQuery.java b/drivers/src/main/java/org/onosproject/driver/query/OFOpticalSwitch13LambdaQuery.java
new file mode 100644
index 0000000..f01a266
--- /dev/null
+++ b/drivers/src/main/java/org/onosproject/driver/query/OFOpticalSwitch13LambdaQuery.java
@@ -0,0 +1,63 @@
+/*
+ * Copyright 2016 Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.onosproject.driver.query;
+
+import org.onosproject.net.ChannelSpacing;
+import org.onosproject.net.OchSignal;
+import org.onosproject.net.OmsPort;
+import org.onosproject.net.Port;
+import org.onosproject.net.PortNumber;
+import org.onosproject.net.behaviour.LambdaQuery;
+import org.onosproject.net.device.DeviceService;
+import org.onosproject.net.driver.AbstractHandlerBehaviour;
+
+import java.util.Collections;
+import java.util.Set;
+import java.util.stream.Collectors;
+import java.util.stream.IntStream;
+
+/**
+ * Lambda query implementation for OFOpticalSwitch13.
+ *
+ * Note: Standard (ONF TS-022, March 15, 2015) does not support negative values for spacingMultiplier in exp_OCH_sigid.
+ * Thus, Lambda values cannot be calculated using center and spacingMultiplier of +/- values.
+ * Therefore, Lambda values are calculated with positive values only: starting from min-frequency of 191.7 THz.
+ *
+ * TODO: When standard is fixed - modify queryLambdas accordingly.
+ *
+ * OFOpticalSwitch13 exposes OchSignal resources: 'lambdaCount' lambdas with 50GHz width (fixed grid)
+ * starting from min-frequency of 191.7 THz.
+ */
+
+public class OFOpticalSwitch13LambdaQuery extends AbstractHandlerBehaviour implements LambdaQuery {
+
+    @Override
+    public Set<OchSignal> queryLambdas(PortNumber port) {
+        DeviceService deviceService = this.handler().get(DeviceService.class);
+        Port p = deviceService.getPort(this.data().deviceId(), port);
+
+        // Only OMS ports expose lambda resources
+        if (!p.type().equals(Port.Type.OMS)) {
+            return Collections.emptySet();
+        }
+
+        short lambdaCount = ((OmsPort) p).totalChannels();
+        // OMS ports expose 'lambdaCount' fixed grid lambdas of 50GHz width, starting from min-frequency 191.7 THz.
+        return IntStream.rangeClosed(1, lambdaCount)
+                .mapToObj(x -> OchSignal.newDwdmSlot(ChannelSpacing.CHL_50GHZ, x))
+                .collect(Collectors.toSet());
+    }
+}
diff --git a/drivers/src/main/resources/onos-drivers.xml b/drivers/src/main/resources/onos-drivers.xml
index 423ec85..7ae184a 100644
--- a/drivers/src/main/resources/onos-drivers.xml
+++ b/drivers/src/main/resources/onos-drivers.xml
@@ -175,6 +175,8 @@
                    impl="org.onosproject.driver.handshaker.OFOpticalSwitch13"/>
         <behaviour api="org.onosproject.net.behaviour.TributarySlotQuery"
                    impl="org.onosproject.driver.query.DefaultTributarySlotQuery" />
+        <behaviour api="org.onosproject.net.behaviour.LambdaQuery"
+                   impl="org.onosproject.driver.query.OFOpticalSwitch13LambdaQuery"/>
     </driver>
     <driver name="aos" extends="ofdpa"
             manufacturer="Accton" hwVersion=".*" swVersion="1.*">
diff --git a/providers/openflow/device/src/main/java/org/onosproject/provider/of/device/impl/OpenFlowDeviceProvider.java b/providers/openflow/device/src/main/java/org/onosproject/provider/of/device/impl/OpenFlowDeviceProvider.java
index 28b4afd..fe7f702 100644
--- a/providers/openflow/device/src/main/java/org/onosproject/provider/of/device/impl/OpenFlowDeviceProvider.java
+++ b/providers/openflow/device/src/main/java/org/onosproject/provider/of/device/impl/OpenFlowDeviceProvider.java
@@ -123,7 +123,8 @@
     //TODO consider renaming KBPS and MBPS (as they are used to convert by division)
     private static final long KBPS = 1_000;
     private static final long MBPS = 1_000 * 1_000;
-    private static final Frequency FREQ100 = Frequency.ofGHz(100);
+    private static final Frequency FREQ50 = Frequency.ofGHz(50);
+    private static final Frequency FREQ191_7 = Frequency.ofGHz(191_700);
     private static final Frequency FREQ4_4 = Frequency.ofGHz(4_400);
 
     @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
@@ -598,7 +599,7 @@
             switch (sigType) {
             case OMSN:
                 portDes =  new OmsPortDescription(portNo, enabled,
-                        Spectrum.CENTER_FREQUENCY, Spectrum.CENTER_FREQUENCY.add(FREQ4_4), FREQ100, annotations);
+                        FREQ191_7, FREQ191_7.add(FREQ4_4), FREQ50, annotations);
                 break;
             case OCH:
                 OFExpPortOpticalTransportLayerEntry entry = firstProp.getFeatures().get(0).getValue().get(0);