diff --git a/core/api/src/main/java/org/onosproject/net/behaviour/upf/GtpTunnel.java b/core/api/src/main/java/org/onosproject/net/behaviour/upf/GtpTunnel.java
new file mode 100644
index 0000000..bc262c7
--- /dev/null
+++ b/core/api/src/main/java/org/onosproject/net/behaviour/upf/GtpTunnel.java
@@ -0,0 +1,188 @@
+/*
+ * Copyright 2021-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.behaviour.upf;
+
+import org.onlab.packet.Ip4Address;
+import org.onlab.util.ImmutableByteSequence;
+
+import java.util.Objects;
+
+import static com.google.common.base.Preconditions.checkNotNull;
+
+/**
+ * A structure representing a unidirectional GTP tunnel.
+ */
+public final class GtpTunnel {
+    private final Ip4Address src;  // The source address of the unidirectional tunnel
+    private final Ip4Address dst;  // The destination address of the unidirectional tunnel
+    private final ImmutableByteSequence teid;  // Tunnel Endpoint Identifier
+    private final short srcPort;  // Tunnel destination port, default 2152
+
+    private GtpTunnel(Ip4Address src, Ip4Address dst, ImmutableByteSequence teid,
+                      Short srcPort) {
+        this.src = src;
+        this.dst = dst;
+        this.teid = teid;
+        this.srcPort = srcPort;
+    }
+
+    public static GtpTunnelBuilder builder() {
+        return new GtpTunnelBuilder();
+    }
+
+    @Override
+    public String toString() {
+        return String.format("GTP-Tunnel(%s -> %s, TEID:%s)",
+                             src.toString(), dst.toString(), teid.toString());
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (obj == this) {
+            return true;
+        }
+        if (obj == null) {
+            return false;
+        }
+        if (getClass() != obj.getClass()) {
+            return false;
+        }
+        GtpTunnel that = (GtpTunnel) obj;
+
+        return (this.src.equals(that.src) &&
+                this.dst.equals(that.dst) &&
+                this.teid.equals(that.teid) &&
+                (this.srcPort == that.srcPort));
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(src, dst, teid, srcPort);
+    }
+
+    /**
+     * Get the source IP address of this unidirectional GTP tunnel.
+     *
+     * @return tunnel source IP
+     */
+    public Ip4Address src() {
+        return this.src;
+    }
+
+    /**
+     * Get the destination address of this unidirectional GTP tunnel.
+     *
+     * @return tunnel destination IP
+     */
+    public Ip4Address dst() {
+        return this.dst;
+    }
+
+    /**
+     * Get the ID of this unidirectional GTP tunnel.
+     *
+     * @return tunnel ID
+     */
+    public ImmutableByteSequence teid() {
+        return this.teid;
+    }
+
+
+    /**
+     * Get the source L4 port of this unidirectional GTP tunnel.
+     *
+     * @return tunnel source port
+     */
+    public Short srcPort() {
+        return this.srcPort;
+    }
+
+    public static class GtpTunnelBuilder {
+        private Ip4Address src;
+        private Ip4Address dst;
+        private ImmutableByteSequence teid;
+        private short srcPort = 2152;  // Default value is equal to GTP tunnel dst port
+
+        public GtpTunnelBuilder() {
+            this.src = null;
+            this.dst = null;
+            this.teid = null;
+        }
+
+        /**
+         * Set the source IP address of the unidirectional GTP tunnel.
+         *
+         * @param src GTP tunnel source IP
+         * @return This builder object
+         */
+        public GtpTunnelBuilder setSrc(Ip4Address src) {
+            this.src = src;
+            return this;
+        }
+
+        /**
+         * Set the destination IP address of the unidirectional GTP tunnel.
+         *
+         * @param dst GTP tunnel destination IP
+         * @return This builder object
+         */
+        public GtpTunnelBuilder setDst(Ip4Address dst) {
+            this.dst = dst;
+            return this;
+        }
+
+        /**
+         * Set the identifier of this unidirectional GTP tunnel.
+         *
+         * @param teid tunnel ID
+         * @return This builder object
+         */
+        public GtpTunnelBuilder setTeid(ImmutableByteSequence teid) {
+            this.teid = teid;
+            return this;
+        }
+
+        /**
+         * Set the identifier of this unidirectional GTP tunnel.
+         *
+         * @param teid tunnel ID
+         * @return This builder object
+         */
+        public GtpTunnelBuilder setTeid(long teid) {
+            this.teid = ImmutableByteSequence.copyFrom(teid);
+            return this;
+        }
+
+        /**
+         * Set the source port of this unidirectional GTP tunnel.
+         *
+         * @param srcPort tunnel source port
+         * @return this builder object
+         */
+        public GtpTunnelBuilder setSrcPort(short srcPort) {
+            this.srcPort = srcPort;
+            return this;
+        }
+
+        public GtpTunnel build() {
+            checkNotNull(src, "Tunnel source address cannot be null");
+            checkNotNull(dst, "Tunnel destination address cannot be null");
+            checkNotNull(teid, "Tunnel TEID cannot be null");
+            return new GtpTunnel(this.src, this.dst, this.teid, srcPort);
+        }
+    }
+}