diff --git a/core/api/src/main/java/org/onosproject/net/pi/runtime/PiRegisterCellId.java b/core/api/src/main/java/org/onosproject/net/pi/runtime/PiRegisterCellId.java
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+++ b/core/api/src/main/java/org/onosproject/net/pi/runtime/PiRegisterCellId.java
@@ -0,0 +1,94 @@
+/*
+ * Copyright 2018-present Open Networking Foundation
+ *
+ * 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.net.pi.runtime;
+
+import com.google.common.annotations.Beta;
+import com.google.common.base.Objects;
+import org.onosproject.net.pi.model.PiRegisterId;
+
+import static com.google.common.base.Preconditions.checkArgument;
+import static com.google.common.base.Preconditions.checkNotNull;
+
+/**
+ * Identifier of a register cell in a protocol-independent pipeline.
+ */
+@Beta
+public final class PiRegisterCellId {
+
+    private final PiRegisterId registerId;
+    private final long index;
+
+    private PiRegisterCellId(PiRegisterId registerId, long index) {
+        this.registerId = registerId;
+        this.index = index;
+    }
+
+    /**
+     * Returns the identifier of the register instance where this cell is
+     * contained.
+     *
+     * @return register identifier
+     */
+    public PiRegisterId registerId() {
+        return registerId;
+    }
+
+    /**
+     * Returns the register index to which this cell ID is associated.
+     *
+     * @return register index
+     */
+    public long index() {
+        return index;
+    }
+
+    /**
+     * Return a register cell ID for the given register ID and index.
+     *
+     * @param registerId register ID
+     * @param index     index
+     * @return register cell ID
+     */
+    public static PiRegisterCellId of(PiRegisterId registerId, long index) {
+        checkNotNull(registerId);
+        checkArgument(index >= 0, "Index must be a positive number");
+        return new PiRegisterCellId(registerId, index);
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) {
+            return true;
+        }
+        if (obj == null || getClass() != obj.getClass()) {
+            return false;
+        }
+        final PiRegisterCellId other = (PiRegisterCellId) obj;
+        return Objects.equal(this.registerId, other.registerId)
+                && Objects.equal(this.index, other.index);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hashCode(registerId, index);
+    }
+
+    @Override
+    public String toString() {
+        return registerId.toString() + ':' + String.valueOf(index);
+    }
+}
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