diff --git a/incubator/api/src/main/java/org/onosproject/incubator/net/faultmanagement/alarm/DefaultAlarm.java b/incubator/api/src/main/java/org/onosproject/incubator/net/faultmanagement/alarm/DefaultAlarm.java
new file mode 100644
index 0000000..afa366a
--- /dev/null
+++ b/incubator/api/src/main/java/org/onosproject/incubator/net/faultmanagement/alarm/DefaultAlarm.java
@@ -0,0 +1,309 @@
+/*
+ * Copyright 2014-2015 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.incubator.net.faultmanagement.alarm;
+
+import org.onosproject.net.DeviceId;
+
+import java.util.Objects;
+
+import static com.google.common.base.MoreObjects.toStringHelper;
+import static com.google.common.base.Preconditions.checkNotNull;
+
+/**
+ * Default implementation of an alarm.
+ */
+public final class DefaultAlarm implements Alarm {
+
+    private final AlarmId id;
+
+    private final DeviceId deviceId;
+    private final String description;
+    private final AlarmEntityId source;
+    private final long timeRaised;
+    private final long timeUpdated;
+    private final Long timeCleared;
+    private final SeverityLevel severity;
+    private final boolean isServiceAffecting;
+    private final boolean isAcknowledged;
+    private final boolean isManuallyClearable;
+    private final String assignedUser;
+
+    /**
+     * Instantiates a new Default alarm.
+     *
+     * @param id the id
+     * @param deviceId the device id
+     * @param description the description
+     * @param source the source, null indicates none.
+     * @param timeRaised the time raised.
+     * @param timeUpdated the time last updated.
+     * @param timeCleared the time cleared, null indicates uncleared.
+     * @param severity the severity
+     * @param isServiceAffecting the service affecting
+     * @param isAcknowledged the acknowledged
+     * @param isManuallyClearable the manually clearable
+     * @param assignedUser the assigned user, `null` indicates none.
+     */
+    private DefaultAlarm(final AlarmId id,
+            final DeviceId deviceId,
+            final String description,
+            final AlarmEntityId source,
+            final long timeRaised,
+            final long timeUpdated,
+            final Long timeCleared,
+            final SeverityLevel severity,
+            final boolean isServiceAffecting,
+            final boolean isAcknowledged,
+            final boolean isManuallyClearable,
+            final String assignedUser) {
+        this.id = id;
+        this.deviceId = deviceId;
+        this.description = description;
+        this.source = source;
+        this.timeRaised = timeRaised;
+        this.timeUpdated = timeUpdated;
+        this.timeCleared = timeCleared;
+        this.severity = severity;
+        this.isServiceAffecting = isServiceAffecting;
+        this.isAcknowledged = isAcknowledged;
+        this.isManuallyClearable = isManuallyClearable;
+        this.assignedUser = assignedUser;
+    }
+
+    @Override
+    public AlarmId id() {
+        return id;
+    }
+
+    @Override
+    public DeviceId deviceId() {
+        return deviceId;
+    }
+
+    @Override
+    public String description() {
+        return description;
+    }
+
+    @Override
+    public AlarmEntityId source() {
+        return source;
+    }
+
+    @Override
+    public long timeRaised() {
+        return timeRaised;
+    }
+
+    @Override
+    public long timeUpdated() {
+        return timeUpdated;
+    }
+
+    @Override
+    public Long timeCleared() {
+        return timeCleared;
+    }
+
+    @Override
+    public SeverityLevel severity() {
+        return severity;
+    }
+
+    @Override
+    public boolean serviceAffecting() {
+        return isServiceAffecting;
+    }
+
+    @Override
+    public boolean acknowledged() {
+        return isAcknowledged;
+    }
+
+    @Override
+    public boolean manuallyClearable() {
+        return isManuallyClearable;
+    }
+
+    @Override
+    public String assignedUser() {
+        return assignedUser;
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(id, deviceId, description,
+                source, timeRaised, timeUpdated, timeCleared, severity,
+                isServiceAffecting, isAcknowledged,
+                isManuallyClearable, assignedUser);
+    }
+
+    @Override
+    public boolean equals(final Object obj) {
+        if (obj == null) {
+            return false;
+        }
+        if (getClass() != obj.getClass()) {
+            return false;
+        }
+        final DefaultAlarm other = (DefaultAlarm) obj;
+        if (!Objects.equals(this.id, other.id)) {
+            return false;
+        }
+        if (!Objects.equals(this.deviceId, other.deviceId)) {
+            return false;
+        }
+        if (!Objects.equals(this.description, other.description)) {
+            return false;
+        }
+        if (!Objects.equals(this.source, other.source)) {
+            return false;
+        }
+        if (this.timeRaised != other.timeRaised) {
+            return false;
+        }
+        if (this.timeUpdated != other.timeUpdated) {
+            return false;
+        }
+        if (!Objects.equals(this.timeCleared, other.timeCleared)) {
+            return false;
+        }
+        if (this.severity != other.severity) {
+            return false;
+        }
+        if (this.isServiceAffecting != other.isServiceAffecting) {
+            return false;
+        }
+        if (this.isAcknowledged != other.isAcknowledged) {
+            return false;
+        }
+        if (this.isManuallyClearable != other.isManuallyClearable) {
+            return false;
+        }
+        if (!Objects.equals(this.assignedUser, other.assignedUser)) {
+            return false;
+        }
+        return true;
+    }
+
+    @Override
+    public String toString() {
+        return toStringHelper(this)
+                .add("id", id)
+                .add("deviceId", deviceId)
+                .add("description", description)
+                .add("source", source)
+                .add("timeRaised", timeRaised)
+                .add("timeUpdated", timeUpdated)
+                .add("timeCleared", timeCleared)
+                .add("severity", severity)
+                .add("serviceAffecting", isServiceAffecting)
+                .add("acknowledged", isAcknowledged)
+                .add("manuallyClearable", isManuallyClearable)
+                .add("assignedUser", assignedUser)
+                .toString();
+    }
+
+    public static class Builder {
+
+        // Manadatory fields ..
+        private final AlarmId id;
+        private final DeviceId deviceId;
+        private final String description;
+        private final SeverityLevel severity;
+        private final long timeRaised;
+
+        // Optional fields ..
+        private AlarmEntityId source = AlarmEntityId.NONE;
+        private long timeUpdated;
+        private Long timeCleared = null;
+        private boolean isServiceAffecting = false;
+        private boolean isAcknowledged = false;
+        private boolean isManuallyClearable = false;
+        private String assignedUser = null;
+
+        public Builder(final Alarm alarm) {
+            this(alarm.id(), alarm.deviceId(), alarm.description(), alarm.severity(), alarm.timeRaised());
+            this.source = AlarmEntityId.NONE;
+            this.timeUpdated = alarm.timeUpdated();
+            this.timeCleared = alarm.timeCleared();
+            this.isServiceAffecting = alarm.serviceAffecting();
+            this.isAcknowledged = alarm.acknowledged();
+            this.isManuallyClearable = alarm.manuallyClearable();
+            this.assignedUser = alarm.assignedUser();
+
+        }
+
+        public Builder(final AlarmId id, final DeviceId deviceId,
+                final String description, final SeverityLevel severity, final long timeRaised) {
+            super();
+            this.id = id;
+            this.deviceId = deviceId;
+            this.description = description;
+            this.severity = severity;
+            this.timeRaised = timeRaised;
+            // Unless specified time-updated is same as raised.
+            this.timeUpdated = timeRaised;
+        }
+
+        public Builder forSource(final AlarmEntityId source) {
+            this.source = source;
+            return this;
+        }
+
+        public Builder withTimeUpdated(final long timeUpdated) {
+            this.timeUpdated = timeUpdated;
+            return this;
+        }
+
+        public Builder withTimeCleared(final Long timeCleared) {
+            this.timeCleared = timeCleared;
+            return this;
+        }
+
+        public Builder withServiceAffecting(final boolean isServiceAffecting) {
+            this.isServiceAffecting = isServiceAffecting;
+            return this;
+        }
+
+        public Builder withAcknowledged(final boolean isAcknowledged) {
+            this.isAcknowledged = isAcknowledged;
+            return this;
+        }
+
+        public Builder withManuallyClearable(final boolean isManuallyClearable) {
+            this.isManuallyClearable = isManuallyClearable;
+            return this;
+        }
+
+        public Builder withAssignedUser(final String assignedUser) {
+            this.assignedUser = assignedUser;
+            return this;
+        }
+
+        public DefaultAlarm build() {
+            checkNotNull(id, "Must specify an alarm id");
+            checkNotNull(deviceId, "Must specify a device");
+            checkNotNull(description, "Must specify a description");
+            checkNotNull(timeRaised, "Must specify a time raised");
+            checkNotNull(timeUpdated, "Must specify a time updated");
+            checkNotNull(severity, "Must specify a severity");
+
+            return new DefaultAlarm(id, deviceId, description, source, timeRaised, timeUpdated, timeCleared,
+                    severity, isServiceAffecting, isAcknowledged, isManuallyClearable, assignedUser);
+        }
+    }
+}