diff --git a/core/api/src/main/java/org/onosproject/net/behaviour/upf/PacketDetectionRule.java b/core/api/src/main/java/org/onosproject/net/behaviour/upf/PacketDetectionRule.java
new file mode 100644
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+++ b/core/api/src/main/java/org/onosproject/net/behaviour/upf/PacketDetectionRule.java
@@ -0,0 +1,425 @@
+/*
+ * 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.checkArgument;
+
+/**
+ * A single Packet Detection Rule (PDR), an entity described in the 3GPP
+ * specifications (although that does not mean that this class is 3GPP
+ * compliant). An instance of this class will be generated by a logical switch
+ * write request to the database-style PDR P4 table, and the resulting instance
+ * should contain all the information needed to reproduce that logical switch
+ * PDR in the event of a client read request. The instance should also contain
+ * sufficient information (or expose the means to retrieve such information) to
+ * generate the corresponding dataplane forwarding state that implements the PDR.
+ */
+public final class PacketDetectionRule {
+    // Match keys
+    private final Ip4Address ueAddr;  // The UE IP address that this PDR matches on
+    private final ImmutableByteSequence teid;  // The Tunnel Endpoint ID that this PDR matches on
+    private final Ip4Address tunnelDst;  // The tunnel destination address that this PDR matches on
+    // Action parameters
+    private final ImmutableByteSequence sessionId;  // The ID of the PFCP session that created this PDR
+    private final Integer ctrId;  // Counter ID unique to this PDR
+    private final Integer farId;  // The PFCP session-local ID of the FAR that should apply after this PDR hits
+    private final Type type;
+    private final Integer schedulingPriority;
+
+    private static final int SESSION_ID_BITWIDTH = 96;
+
+    private PacketDetectionRule(ImmutableByteSequence sessionId, Integer ctrId,
+                                Integer farId, Integer schedulingPriority,
+                                Ip4Address ueAddr, ImmutableByteSequence teid,
+                                Ip4Address tunnelDst, Type type) {
+        this.ueAddr = ueAddr;
+        this.teid = teid;
+        this.tunnelDst = tunnelDst;
+        this.sessionId = sessionId;
+        this.ctrId = ctrId;
+        this.farId = farId;
+        this.schedulingPriority = schedulingPriority;
+        this.type = type;
+    }
+
+    public static Builder builder() {
+        return new Builder();
+    }
+
+    /**
+     * Return a string representing the match conditions of this PDR.
+     *
+     * @return a string representing the PDR match conditions
+     */
+    public String matchString() {
+        if (matchesEncapped()) {
+            return String.format("Match(Dst=%s, TEID=%s)", tunnelDest(), teid());
+        } else {
+            return String.format("Match(Dst=%s, !GTP)", ueAddress());
+        }
+    }
+
+    @Override
+    public String toString() {
+        String actionParams = "";
+        if (hasActionParameters()) {
+            actionParams = String.format("SEID=%s, FAR=%d, CtrIdx=%d, SchedulingPrio=%d",
+                                         sessionId.toString(), farId, ctrId, schedulingPriority);
+        }
+
+        return String.format("PDR{%s -> LoadParams(%s)}",
+                             matchString(), actionParams);
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (obj == this) {
+            return true;
+        }
+        if (obj == null) {
+            return false;
+        }
+        if (getClass() != obj.getClass()) {
+            return false;
+        }
+        PacketDetectionRule that = (PacketDetectionRule) obj;
+
+        // Safe comparisons between potentially null objects
+        return (this.type.equals(that.type) &&
+                Objects.equals(this.teid, that.teid) &&
+                Objects.equals(this.tunnelDst, that.tunnelDst) &&
+                Objects.equals(this.ueAddr, that.ueAddr) &&
+                Objects.equals(this.ctrId, that.ctrId) &&
+                Objects.equals(this.sessionId, that.sessionId) &&
+                Objects.equals(this.farId, that.farId) &&
+                Objects.equals(this.schedulingPriority, that.schedulingPriority));
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(ueAddr, teid, tunnelDst, sessionId, ctrId, farId,
+                            schedulingPriority, type);
+    }
+
+    /**
+     * Instances created as a result of DELETE write requests will not have
+     * action parameters, only match keys. This method should be used to avoid
+     * null pointer exceptions in those instances.
+     *
+     * @return true if this instance has PDR action parameters, false otherwise.
+     */
+    public boolean hasActionParameters() {
+        return type == Type.MATCH_ENCAPPED || type == Type.MATCH_UNENCAPPED;
+    }
+
+    /**
+     * Return a new instance of this PDR with the action parameters stripped,
+     * leaving only the match keys.
+     *
+     * @return a new PDR with only match keys
+     */
+    public PacketDetectionRule withoutActionParams() {
+        if (matchesEncapped()) {
+            return PacketDetectionRule.builder()
+                    .withTeid(teid)
+                    .withTunnelDst(tunnelDst)
+                    .build();
+        } else {
+            return PacketDetectionRule.builder()
+                    .withUeAddr(ueAddr).build();
+        }
+    }
+
+    /**
+     * True if this PDR matches on packets received with a GTP header, and false
+     * otherwise.
+     *
+     * @return true if the PDR matches only encapsulated packets
+     */
+    public boolean matchesEncapped() {
+        return type == Type.MATCH_ENCAPPED ||
+                type == Type.MATCH_ENCAPPED_NO_ACTION;
+    }
+
+    /**
+     * True if this PDR matches on packets received without a GTP header, and
+     * false otherwise.
+     *
+     * @return true if the PDR matches only un-encapsulated packets
+     */
+    public boolean matchesUnencapped() {
+        return type == Type.MATCH_UNENCAPPED ||
+                type == Type.MATCH_UNENCAPPED_NO_ACTION;
+    }
+
+    /**
+     * Get the ID of the PFCP session that produced this PDR.
+     *
+     * @return PFCP session ID
+     */
+    public ImmutableByteSequence sessionId() {
+        return sessionId;
+    }
+
+    /**
+     * Get the UE IP address that this PDR matches on.
+     *
+     * @return UE IP address
+     */
+    public Ip4Address ueAddress() {
+        return ueAddr;
+    }
+
+    /**
+     * Get the identifier of the GTP tunnel that this PDR matches on.
+     *
+     * @return GTP tunnel ID
+     */
+    public ImmutableByteSequence teid() {
+        return teid;
+    }
+
+    /**
+     * Get the destination IP of the GTP tunnel that this PDR matches on.
+     *
+     * @return GTP tunnel destination IP
+     */
+    public Ip4Address tunnelDest() {
+        return tunnelDst;
+    }
+
+    /**
+     * Get the dataplane PDR counter cell ID that this PDR is assigned.
+     *
+     * @return PDR counter cell ID
+     */
+    public int counterId() {
+        return ctrId;
+    }
+
+    /**
+     * Get the PFCP session-local ID of the far that should apply to packets
+     * that this PDR matches.
+     *
+     * @return PFCP session-local FAR ID
+     */
+    public int farId() {
+        return farId;
+    }
+
+    /**
+     * Get the scheduling priority that this PDR is assigned.
+     *
+     * @return scheduling priority
+     */
+    public int schedulingPriority() {
+        return schedulingPriority;
+    }
+
+    /**
+     * This method is used to differentiate between prioritized and non-prioritized
+     * flows.
+     *
+     * @return true if scheduling priority is assigned.
+     */
+    public boolean hasSchedulingPriority() {
+        return schedulingPriority > 0;
+    }
+
+    private enum Type {
+        /**
+         * Match on packets that are encapsulated in a GTP tunnel.
+         */
+        MATCH_ENCAPPED,
+        /**
+         * Match on packets that are not encapsulated in a GTP tunnel.
+         */
+        MATCH_UNENCAPPED,
+        /**
+         * For PDRs that match on encapsulated packets but do not yet have any
+         * action parameters set.
+         * These are usually built in the context of P4Runtime DELETE write requests.
+         */
+        MATCH_ENCAPPED_NO_ACTION,
+        /**
+         * For PDRs that match on unencapsulated packets but do not yet have any
+         * action parameters set.
+         * These are usually built in the context of P4Runtime DELETE write requests.
+         */
+        MATCH_UNENCAPPED_NO_ACTION
+    }
+
+    public static class Builder {
+        private ImmutableByteSequence sessionId = null;
+        private Integer ctrId = null;
+        private Integer localFarId = null;
+        private Integer schedulingPriority = null;
+        private Ip4Address ueAddr = null;
+        private ImmutableByteSequence teid = null;
+        private Ip4Address tunnelDst = null;
+
+        public Builder() {
+
+        }
+
+        /**
+         * Set the ID of the PFCP session that produced this PDR.
+         *
+         * @param sessionId PFCP session ID
+         * @return This builder object
+         */
+        public Builder withSessionId(ImmutableByteSequence sessionId) {
+            this.sessionId = sessionId;
+            return this;
+        }
+
+        /**
+         * Set the ID of the PFCP session that produced this PDR.
+         *
+         * @param sessionId PFCP session ID
+         * @return This builder object
+         */
+        public Builder withSessionId(long sessionId) {
+            try {
+                this.sessionId = ImmutableByteSequence.copyFrom(sessionId)
+                        .fit(SESSION_ID_BITWIDTH);
+            } catch (ImmutableByteSequence.ByteSequenceTrimException e) {
+                // This error is literally impossible
+            }
+            return this;
+        }
+
+        /**
+         * Set the UE IP address that this PDR matches on.
+         *
+         * @param ueAddr UE IP address
+         * @return This builder object
+         */
+        public Builder withUeAddr(Ip4Address ueAddr) {
+            this.ueAddr = ueAddr;
+            return this;
+        }
+
+        /**
+         * Set the dataplane PDR counter cell ID that this PDR is assigned.
+         *
+         * @param ctrId PDR counter cell ID
+         * @return This builder object
+         */
+        public Builder withCounterId(int ctrId) {
+            this.ctrId = ctrId;
+            return this;
+        }
+
+
+        /**
+         * Set the PFCP session-local ID of the far that should apply to packets that this PDR matches.
+         *
+         * @param localFarId PFCP session-local FAR ID
+         * @return This builder object
+         */
+        public Builder withLocalFarId(int localFarId) {
+            this.localFarId = localFarId;
+            return this;
+        }
+
+        public Builder withSchedulingPriority(int schedulingPriority) {
+            this.schedulingPriority = schedulingPriority;
+            return this;
+        }
+
+        /**
+         * Set the identifier of the GTP tunnel that this PDR matches on.
+         *
+         * @param teid GTP tunnel ID
+         * @return This builder object
+         */
+        public Builder withTeid(int teid) {
+            this.teid = ImmutableByteSequence.copyFrom(teid);
+            return this;
+        }
+
+        /**
+         * Set the identifier of the GTP tunnel that this PDR matches on.
+         *
+         * @param teid GTP tunnel ID
+         * @return This builder object
+         */
+        public Builder withTeid(ImmutableByteSequence teid) {
+            this.teid = teid;
+            return this;
+        }
+
+        /**
+         * Set the destination IP of the GTP tunnel that this PDR matches on.
+         *
+         * @param tunnelDst GTP tunnel destination IP
+         * @return This builder object
+         */
+        public Builder withTunnelDst(Ip4Address tunnelDst) {
+            this.tunnelDst = tunnelDst;
+            return this;
+        }
+
+        /**
+         * Set the tunnel ID and destination IP of the GTP tunnel that this PDR matches on.
+         *
+         * @param teid      GTP tunnel ID
+         * @param tunnelDst GTP tunnel destination IP
+         * @return This builder object
+         */
+        public Builder withTunnel(ImmutableByteSequence teid, Ip4Address tunnelDst) {
+            this.teid = teid;
+            this.tunnelDst = tunnelDst;
+            return this;
+        }
+
+        public PacketDetectionRule build() {
+            // Some match keys are required.
+            checkArgument(
+                    (ueAddr != null && teid == null && tunnelDst == null) ||
+                            (ueAddr == null && teid != null && tunnelDst != null),
+                    "Either a UE address or a TEID and Tunnel destination must be provided, but not both.");
+            // Action parameters are optional but must be all provided together if they are provided
+            checkArgument(
+                    (sessionId != null && ctrId != null && localFarId != null && schedulingPriority != null) ||
+                            (sessionId == null && ctrId == null && localFarId == null && schedulingPriority == null),
+                    "PDR action parameters must be provided together or not at all.");
+            Type type;
+            if (teid != null) {
+                if (sessionId != null) {
+                    type = Type.MATCH_ENCAPPED;
+                } else {
+                    type = Type.MATCH_ENCAPPED_NO_ACTION;
+                }
+            } else {
+                if (sessionId != null) {
+                    type = Type.MATCH_UNENCAPPED;
+                } else {
+                    type = Type.MATCH_UNENCAPPED_NO_ACTION;
+                }
+            }
+            return new PacketDetectionRule(sessionId, ctrId, localFarId, schedulingPriority,
+                                           ueAddr, teid, tunnelDst, type);
+        }
+    }
+}