diff --git a/core/net/src/main/java/org/onosproject/net/pi/impl/AbstractCriterionTranslator.java b/core/net/src/main/java/org/onosproject/net/pi/impl/AbstractCriterionTranslator.java
new file mode 100644
index 0000000..80639b4
--- /dev/null
+++ b/core/net/src/main/java/org/onosproject/net/pi/impl/AbstractCriterionTranslator.java
@@ -0,0 +1,172 @@
+/*
+ * Copyright 2017-present 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.net.pi.impl;
+
+import org.apache.commons.lang3.tuple.Pair;
+import org.onlab.util.ImmutableByteSequence;
+import org.onosproject.net.pi.model.PiMatchType;
+
+import java.util.Optional;
+
+import static org.onlab.util.ImmutableByteSequence.ByteSequenceTrimException;
+import static org.onlab.util.ImmutableByteSequence.fit;
+
+/**
+ * Abstract implementation of a criterion translator that opportunistically tries to generate different types of match
+ * based on an initialization method. It throws an exception when a safe translation is not possible, e.g. when trying
+ * to translate a masked criterion to an exact match.
+ */
+abstract class AbstractCriterionTranslator implements CriterionTranslator {
+
+    private PiMatchType initType;
+    private int bitWidth;
+    private ImmutableByteSequence value;
+    private ImmutableByteSequence mask;
+    private Integer prefixLength;
+
+    /**
+     * Initializes the translator as an exact match.
+     *
+     * @param value     exact match value
+     * @param bitWidth  field bit-width
+     * @throws ByteSequenceTrimException if the match value cannot be trimmed to fit the field match bit-width
+     */
+    void initAsExactMatch(ImmutableByteSequence value, int bitWidth)
+            throws ByteSequenceTrimException {
+        this.value = fit(value, bitWidth);
+        this.bitWidth = bitWidth;
+        this.initType = PiMatchType.EXACT;
+    }
+
+    /**
+     * Initializes the translator as a ternary match.
+     *
+     * @param value     match value
+     * @param mask      match mask
+     * @param bitWidth  field bit-width
+     * @throws ByteSequenceTrimException if the match value or mask cannot be trimmed to fit the field match bit-width
+     */
+    void initAsTernaryMatch(ImmutableByteSequence value, ImmutableByteSequence mask, int bitWidth)
+            throws ByteSequenceTrimException {
+        this.value = fit(value, bitWidth);
+        this.mask = fit(mask, bitWidth);
+        this.bitWidth = bitWidth;
+        this.initType = PiMatchType.TERNARY;
+    }
+
+    /**
+     * Initializes the translator as a longest-prefix match.
+     *
+     * @param value        match value
+     * @param prefixLength prefix length
+     * @param bitWidth     field bit-width
+     * @throws ByteSequenceTrimException if the match value cannot be trimmed to fit the field match bit-width
+     */
+    void initAsLpm(ImmutableByteSequence value, int prefixLength, int bitWidth)
+            throws ByteSequenceTrimException {
+        this.value = fit(value, bitWidth);
+        this.prefixLength = prefixLength;
+        this.bitWidth = bitWidth;
+        this.initType = PiMatchType.LPM;
+    }
+
+    @Override
+    public ImmutableByteSequence exactMatch() throws CriterionTranslatorException {
+        switch (initType) {
+            case EXACT:
+                break;
+            case TERNARY:
+                ImmutableByteSequence exactMask = ImmutableByteSequence.ofOnes(value.size());
+                if (!mask.equals(exactMask)) {
+                    throw new CriterionTranslator.CriterionTranslatorException(
+                            "trying to use masked field as an exact match, but mask is not exact");
+                }
+                break;
+            case LPM:
+                if (prefixLength < bitWidth) {
+                    throw new CriterionTranslator.CriterionTranslatorException(
+                            "trying to use LPM field as an exact match, but prefix is not full");
+                }
+                break;
+            default:
+                throw new RuntimeException("Unrecognized init type " + initType.name());
+        }
+        return value;
+    }
+
+    @Override
+    public Pair<ImmutableByteSequence, ImmutableByteSequence> ternaryMatch() {
+        switch (initType) {
+            case EXACT:
+                mask = ImmutableByteSequence.ofOnes(value.size());
+                break;
+            case TERNARY:
+                break;
+            case LPM:
+                mask = getMaskFromPrefixLength(prefixLength, value.size());
+            default:
+                throw new RuntimeException("Unrecognized init type " + initType.name());
+        }
+
+        return Pair.of(value, mask);
+    }
+
+    @Override
+    public Pair<ImmutableByteSequence, Integer> lpmMatch() throws CriterionTranslatorException {
+        switch (initType) {
+            case EXACT:
+                prefixLength = bitWidth;
+                break;
+            case TERNARY:
+                prefixLength = getPrefixLengthFromMask(mask).orElseThrow(
+                        () -> new CriterionTranslatorException(
+                                "trying to use masked field as a longest-prefix match, " +
+                                        "but mask is not equivalent to a prefix length"));
+                break;
+            case LPM:
+                break;
+            default:
+                throw new RuntimeException("Unrecognized init type " + initType.name());
+        }
+
+        return Pair.of(value, prefixLength);
+    }
+
+    /**
+     * Returns a bit mask equivalent to the given prefix length.
+     *
+     * @param prefixLength prefix length (in bits)
+     * @param maskSize     mask size (in bytes)
+     * @return a byte sequence
+     */
+    private ImmutableByteSequence getMaskFromPrefixLength(int prefixLength, int maskSize) {
+        // TODO: implement.
+        throw new RuntimeException("getMaskFromPrefixLength() not implemented yet.");
+    }
+
+    /**
+     * Checks that the given mask is equivalent to a longest-prefix match and returns the prefix length. If not
+     * possible, the optional value will not be present.
+     *
+     * @param mask byte sequence
+     * @return optional prefix length
+     */
+    private Optional<Integer> getPrefixLengthFromMask(ImmutableByteSequence mask) {
+        // TODO: implement.
+        throw new RuntimeException("getPrefixLengthFromMask() not implemented yet.");
+    }
+}
diff --git a/core/net/src/main/java/org/onosproject/net/pi/impl/CriterionTranslator.java b/core/net/src/main/java/org/onosproject/net/pi/impl/CriterionTranslator.java
new file mode 100644
index 0000000..10b92af
--- /dev/null
+++ b/core/net/src/main/java/org/onosproject/net/pi/impl/CriterionTranslator.java
@@ -0,0 +1,78 @@
+/*
+ * Copyright 2017-present 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.net.pi.impl;
+
+
+import org.apache.commons.lang3.tuple.Pair;
+import org.onlab.util.ImmutableByteSequence;
+import org.onosproject.net.flow.criteria.Criterion;
+
+import static org.onlab.util.ImmutableByteSequence.ByteSequenceTrimException;
+
+/**
+ * A translator of a criterion instance to different match types represented as primitive byte sequences.
+ */
+interface CriterionTranslator {
+
+    /**
+     * Initialize this translator with the given criterion and field match bit-width.
+     *
+     * @param criterion criterion
+     * @param bitWidth  field bit-width
+     * @throws ByteSequenceTrimException if the criterion cannot be trimmed to fit the field match bit-width
+     */
+    void init(Criterion criterion, int bitWidth) throws ByteSequenceTrimException;
+
+    /**
+     * Returns a pair of byte sequences representing a ternary match (value and mask) equivalent to the criterion given
+     * when initialized. The returned byte sequences will have minimum size (i.e. rounded to the nearest byte) to
+     * contain the initialized field bit-width.
+     *
+     * @return a pair of byte sequences with value on the left and mask on the right
+     * @throws CriterionTranslatorException if the criterion cannot be translated
+     */
+    Pair<ImmutableByteSequence, ImmutableByteSequence> ternaryMatch() throws CriterionTranslatorException;
+
+    /**
+     * Returns a pair comprising a byte sequence and a prefix length representing a longest-prefix match equivalent to
+     * the criterion given when initialized. The returned byte sequence will have minimum size (i.e. rounded to the
+     * nearest byte) to contain the initialized field bit-width.
+     *
+     * @return a pair with the match value's byte sequence on the left, and prefix length on the right
+     * @throws CriterionTranslatorException if the criterion cannot be translated
+     */
+    Pair<ImmutableByteSequence, Integer> lpmMatch() throws CriterionTranslatorException;
+
+    /**
+     * Returns a byte sequence representing an exact match equivalent to the criterion given when initialized. The
+     * returned byte sequence will have minimum size (i.e. rounded to the nearest byte) to contain the initialized field
+     * bit-width.
+     *
+     * @return exact match value as a byte sequence
+     * @throws CriterionTranslatorException if the criterion cannot be translated
+     */
+    ImmutableByteSequence exactMatch() throws CriterionTranslatorException;
+
+    /**
+     * Signifies that the criterion cannot be translated.
+     */
+    class CriterionTranslatorException extends Exception {
+        CriterionTranslatorException(String message) {
+            super(message);
+        }
+    }
+}
diff --git a/core/net/src/main/java/org/onosproject/net/pi/impl/CriterionTranslatorHelper.java b/core/net/src/main/java/org/onosproject/net/pi/impl/CriterionTranslatorHelper.java
new file mode 100644
index 0000000..0791f3a
--- /dev/null
+++ b/core/net/src/main/java/org/onosproject/net/pi/impl/CriterionTranslatorHelper.java
@@ -0,0 +1,108 @@
+/*
+ * Copyright 2017-present 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.net.pi.impl;
+
+import com.google.common.collect.ImmutableMap;
+import org.apache.commons.lang3.tuple.Pair;
+import org.onlab.util.ImmutableByteSequence;
+import org.onosproject.net.flow.criteria.Criterion;
+import org.onosproject.net.flow.criteria.EthCriterion;
+import org.onosproject.net.flow.criteria.EthTypeCriterion;
+import org.onosproject.net.flow.criteria.IPCriterion;
+import org.onosproject.net.flow.criteria.PortCriterion;
+import org.onosproject.net.pi.impl.CriterionTranslators.EthCriterionTranslator;
+import org.onosproject.net.pi.impl.CriterionTranslators.EthTypeCriterionTranslator;
+import org.onosproject.net.pi.impl.CriterionTranslators.IpCriterionTranslator;
+import org.onosproject.net.pi.impl.CriterionTranslators.PortCriterionTranslator;
+import org.onosproject.net.pi.model.PiMatchType;
+import org.onosproject.net.pi.runtime.PiExactFieldMatch;
+import org.onosproject.net.pi.runtime.PiFieldMatch;
+import org.onosproject.net.pi.runtime.PiHeaderFieldId;
+import org.onosproject.net.pi.runtime.PiLpmFieldMatch;
+import org.onosproject.net.pi.runtime.PiTernaryFieldMatch;
+
+import java.util.Map;
+
+import static java.lang.String.format;
+import static org.onlab.util.ImmutableByteSequence.ByteSequenceTrimException;
+import static org.onosproject.net.pi.impl.CriterionTranslator.CriterionTranslatorException;
+import static org.onosproject.net.pi.runtime.PiFlowRuleTranslationService.PiFlowRuleTranslationException;
+
+/**
+ * Helper class to translate criterion instances to PI field matches.
+ */
+final class CriterionTranslatorHelper {
+
+    private static final Map<Class<? extends Criterion>, CriterionTranslator> TRANSLATORS = ImmutableMap.of(
+            // Add here new CriterionTranslator implementations.
+            PortCriterion.class, new PortCriterionTranslator(),
+            EthCriterion.class, new EthCriterionTranslator(),
+            EthTypeCriterion.class, new EthTypeCriterionTranslator(),
+            IPCriterion.class, new IpCriterionTranslator()
+    );
+
+    private CriterionTranslatorHelper() {
+        // Hides constructor.
+    }
+
+    /**
+     * Translates a given criterion instance to a PiFieldMatch with the given id, match type, and bit-width.
+     *
+     * @param fieldId   PI header field identifier
+     * @param criterion criterion
+     * @param matchType match type
+     * @param bitWidth  size of the field match in bits
+     * @return a PI field match
+     * @throws PiFlowRuleTranslationException if the criterion cannot be translated (see exception message)
+     */
+    static PiFieldMatch translateCriterion(Criterion criterion, PiHeaderFieldId fieldId, PiMatchType matchType,
+                                           int bitWidth)
+            throws PiFlowRuleTranslationException {
+
+        if (!TRANSLATORS.containsKey(criterion.getClass())) {
+            throw new PiFlowRuleTranslationException(format(
+                    "Translation of criterion class %s is not implemented.",
+                    criterion.getClass().getSimpleName()));
+        }
+
+        CriterionTranslator translator = TRANSLATORS.get(criterion.getClass());
+
+        try {
+            translator.init(criterion, bitWidth);
+            switch (matchType) {
+                case EXACT:
+                    return new PiExactFieldMatch(fieldId, translator.exactMatch());
+                case TERNARY:
+                    Pair<ImmutableByteSequence, ImmutableByteSequence> tp = translator.ternaryMatch();
+                    return new PiTernaryFieldMatch(fieldId, tp.getLeft(), tp.getRight());
+                case LPM:
+                    Pair<ImmutableByteSequence, Integer> lp = translator.lpmMatch();
+                    return new PiLpmFieldMatch(fieldId, lp.getLeft(), lp.getRight());
+                default:
+                    throw new PiFlowRuleTranslationException(format(
+                            "Translation of criterion %s (%s class) to match type %s is not implemented.",
+                            criterion.type().name(), criterion.getClass().getSimpleName(), matchType.name()));
+            }
+        } catch (ByteSequenceTrimException e) {
+            throw new PiFlowRuleTranslationException(format(
+                    "Size mismatch for criterion %s: %s", criterion.type(), e.getMessage()));
+        } catch (CriterionTranslatorException e) {
+            throw new PiFlowRuleTranslationException(format(
+                    "Unable to translate criterion %s: %s", criterion.type(), e.getMessage()));
+        }
+    }
+}
diff --git a/core/net/src/main/java/org/onosproject/net/pi/impl/CriterionTranslators.java b/core/net/src/main/java/org/onosproject/net/pi/impl/CriterionTranslators.java
new file mode 100644
index 0000000..089f80a
--- /dev/null
+++ b/core/net/src/main/java/org/onosproject/net/pi/impl/CriterionTranslators.java
@@ -0,0 +1,82 @@
+/*
+ * Copyright 2017-present 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.net.pi.impl;
+
+import org.onlab.util.ImmutableByteSequence;
+import org.onosproject.net.flow.criteria.Criterion;
+import org.onosproject.net.flow.criteria.EthCriterion;
+import org.onosproject.net.flow.criteria.EthTypeCriterion;
+import org.onosproject.net.flow.criteria.IPCriterion;
+import org.onosproject.net.flow.criteria.PortCriterion;
+
+import static org.onlab.util.ImmutableByteSequence.ByteSequenceTrimException;
+import static org.onlab.util.ImmutableByteSequence.copyFrom;
+
+/**
+ * Factory class of criterion translator implementations.
+ */
+final class CriterionTranslators {
+
+    /**
+     * Translator of PortCriterion.
+     */
+    static final class PortCriterionTranslator extends AbstractCriterionTranslator {
+        @Override
+        public void init(Criterion criterion, int bitWidth) throws ByteSequenceTrimException {
+            PortCriterion c = (PortCriterion) criterion;
+            initAsExactMatch(copyFrom(c.port().toLong()), bitWidth);
+        }
+    }
+
+    /**
+     * Translator of EthTypeCriterion.
+     */
+    static final class EthTypeCriterionTranslator extends AbstractCriterionTranslator {
+        @Override
+        public void init(Criterion criterion, int bitWidth) throws ByteSequenceTrimException {
+            EthTypeCriterion c = (EthTypeCriterion) criterion;
+            initAsExactMatch(copyFrom(c.ethType().toShort()), bitWidth);
+        }
+    }
+
+    /**
+     * Translator of EthCriterion.
+     */
+    static final class EthCriterionTranslator extends AbstractCriterionTranslator {
+        @Override
+        public void init(Criterion criterion, int bitWidth) throws ByteSequenceTrimException {
+            EthCriterion c = (EthCriterion) criterion;
+            ImmutableByteSequence value = copyFrom(c.mac().toBytes());
+            if (c.mask() == null) {
+                initAsExactMatch(value, bitWidth);
+            } else {
+                ImmutableByteSequence mask = copyFrom(c.mask().toBytes());
+                initAsTernaryMatch(value, mask, bitWidth);
+            }
+        }
+    }
+
+    /**
+     * Translator of IpCriterion.
+     */
+    static final class IpCriterionTranslator extends AbstractCriterionTranslator {
+        public void init(Criterion criterion, int bitWidth) throws ByteSequenceTrimException {
+            IPCriterion c = (IPCriterion) criterion;
+            initAsLpm(copyFrom(c.ip().address().toOctets()), c.ip().prefixLength(), bitWidth);
+        }
+    }
+}
diff --git a/core/net/src/main/java/org/onosproject/net/pi/impl/PiFlowRuleTranslationServiceImpl.java b/core/net/src/main/java/org/onosproject/net/pi/impl/PiFlowRuleTranslationServiceImpl.java
new file mode 100644
index 0000000..f6f181d
--- /dev/null
+++ b/core/net/src/main/java/org/onosproject/net/pi/impl/PiFlowRuleTranslationServiceImpl.java
@@ -0,0 +1,72 @@
+/*
+ * Copyright 2017-present 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.net.pi.impl;
+
+import org.apache.felix.scr.annotations.Activate;
+import org.apache.felix.scr.annotations.Component;
+import org.apache.felix.scr.annotations.Deactivate;
+import org.apache.felix.scr.annotations.Reference;
+import org.apache.felix.scr.annotations.ReferenceCardinality;
+import org.apache.felix.scr.annotations.Service;
+import org.onosproject.net.Device;
+import org.onosproject.net.device.DeviceService;
+import org.onosproject.net.flow.FlowRule;
+import org.onosproject.net.pi.model.PiPipeconf;
+import org.onosproject.net.pi.runtime.PiFlowRuleTranslationService;
+import org.onosproject.net.pi.runtime.PiTableEntry;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import static org.onosproject.net.pi.impl.PiFlowRuleTranslator.translateFlowRule;
+
+/**
+ * Implementation of the protocol-independent flow rule translation service.
+ */
+@Component(immediate = true)
+@Service
+public class PiFlowRuleTranslationServiceImpl implements PiFlowRuleTranslationService {
+
+    private final Logger log = LoggerFactory.getLogger(this.getClass());
+
+    // TODO: implement cache to speed up translation of flow rules.
+
+    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
+    protected DeviceService deviceService;
+
+    @Activate
+    public void activate() {
+        log.info("Started");
+    }
+
+    @Deactivate
+    public void deactivate() {
+        log.info("Stopped");
+    }
+
+    @Override
+    public PiTableEntry translate(FlowRule rule, PiPipeconf pipeconf)
+            throws PiFlowRuleTranslationException {
+
+        Device device = deviceService.getDevice(rule.deviceId());
+        if (device == null) {
+            throw new PiFlowRuleTranslationException("Unable to get device " + rule.deviceId());
+        }
+
+        return translateFlowRule(rule, pipeconf, device);
+    }
+}
+
diff --git a/core/net/src/main/java/org/onosproject/net/pi/impl/PiFlowRuleTranslator.java b/core/net/src/main/java/org/onosproject/net/pi/impl/PiFlowRuleTranslator.java
new file mode 100644
index 0000000..14f15a5
--- /dev/null
+++ b/core/net/src/main/java/org/onosproject/net/pi/impl/PiFlowRuleTranslator.java
@@ -0,0 +1,429 @@
+/*
+ * Copyright 2017-present 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.net.pi.impl;
+
+import com.google.common.collect.Maps;
+import com.google.common.collect.Sets;
+import org.onlab.util.ImmutableByteSequence;
+import org.onosproject.net.Device;
+import org.onosproject.net.flow.FlowRule;
+import org.onosproject.net.flow.IndexTableId;
+import org.onosproject.net.flow.TrafficSelector;
+import org.onosproject.net.flow.TrafficTreatment;
+import org.onosproject.net.flow.criteria.Criterion;
+import org.onosproject.net.flow.criteria.PiCriterion;
+import org.onosproject.net.flow.instructions.Instruction;
+import org.onosproject.net.flow.instructions.PiInstruction;
+import org.onosproject.net.pi.model.PiActionModel;
+import org.onosproject.net.pi.model.PiActionParamModel;
+import org.onosproject.net.pi.model.PiPipeconf;
+import org.onosproject.net.pi.model.PiPipelineInterpreter;
+import org.onosproject.net.pi.model.PiPipelineModel;
+import org.onosproject.net.pi.model.PiTableMatchFieldModel;
+import org.onosproject.net.pi.model.PiTableModel;
+import org.onosproject.net.pi.runtime.PiAction;
+import org.onosproject.net.pi.runtime.PiActionParam;
+import org.onosproject.net.pi.runtime.PiExactFieldMatch;
+import org.onosproject.net.pi.runtime.PiFieldMatch;
+import org.onosproject.net.pi.runtime.PiHeaderFieldId;
+import org.onosproject.net.pi.runtime.PiLpmFieldMatch;
+import org.onosproject.net.pi.runtime.PiRangeFieldMatch;
+import org.onosproject.net.pi.runtime.PiTableAction;
+import org.onosproject.net.pi.runtime.PiTableEntry;
+import org.onosproject.net.pi.runtime.PiTableId;
+import org.onosproject.net.pi.runtime.PiTernaryFieldMatch;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.Collection;
+import java.util.Map;
+import java.util.Optional;
+import java.util.Set;
+import java.util.StringJoiner;
+
+import static java.lang.String.format;
+import static org.onlab.util.ImmutableByteSequence.ByteSequenceTrimException;
+import static org.onlab.util.ImmutableByteSequence.fit;
+import static org.onosproject.net.flow.criteria.Criterion.Type.PROTOCOL_INDEPENDENT;
+import static org.onosproject.net.pi.impl.CriterionTranslatorHelper.translateCriterion;
+import static org.onosproject.net.pi.runtime.PiFlowRuleTranslationService.PiFlowRuleTranslationException;
+
+/**
+ * Implementation of flow rule translation logic.
+ */
+final class PiFlowRuleTranslator {
+
+    private static final Logger log = LoggerFactory.getLogger(PiFlowRuleTranslationServiceImpl.class);
+
+    private PiFlowRuleTranslator() {
+        // Hide constructor.
+    }
+
+    static PiTableEntry translateFlowRule(FlowRule rule, PiPipeconf pipeconf, Device device)
+            throws PiFlowRuleTranslationException {
+
+        PiPipelineModel pipelineModel = pipeconf.pipelineModel();
+
+        // Retrieve interpreter, if any.
+        // FIXME: get interpreter via driver once implemented.
+        // final PiPipelineInterpreter interpreter = device.is(PiPipelineInterpreter.class)
+        //        ? device.as(PiPipelineInterpreter.class) : null;
+
+        final PiPipelineInterpreter interpreter;
+        try {
+            interpreter = (PiPipelineInterpreter) pipeconf.implementation(PiPipelineInterpreter.class)
+                    .orElse(null)
+                    .newInstance();
+        } catch (InstantiationException | IllegalAccessException e) {
+            throw new PiFlowRuleTranslationException(format(
+                    "Unable to instantiate interpreter of pipeconf %s", pipeconf.id()));
+        }
+
+        PiTableId piTableId;
+        switch (rule.table().type()) {
+            case PIPELINE_INDEPENDENT:
+                piTableId = (PiTableId) rule.table();
+                break;
+            case INDEX:
+                IndexTableId indexId = (IndexTableId) rule.table();
+                if (interpreter == null) {
+                    throw new PiFlowRuleTranslationException(format(
+                            "Unable to map table ID '%d' from index to PI: missing interpreter", indexId.id()));
+                } else if (!interpreter.mapFlowRuleTableId(indexId.id()).isPresent()) {
+                    throw new PiFlowRuleTranslationException(format(
+                            "Unable to map table ID '%d' from index to PI: missing ID in interpreter", indexId.id()));
+                } else {
+                    piTableId = interpreter.mapFlowRuleTableId(indexId.id()).get();
+                }
+                break;
+            default:
+                throw new PiFlowRuleTranslationException(format(
+                        "Unrecognized table ID type %s", rule.table().type().name()));
+        }
+
+        PiTableModel table = pipelineModel.table(piTableId.toString())
+                .orElseThrow(() -> new PiFlowRuleTranslationException(format(
+                        "Not such a table in pipeline model: %s", piTableId)));
+
+        /* Translate selector */
+        Collection<PiFieldMatch> fieldMatches = buildFieldMatches(interpreter, rule.selector(), table);
+
+        /* Translate treatment */
+        PiAction piAction = buildAction(rule.treatment(), interpreter, pipeconf);
+        piAction = typeCheckAction(piAction, table);
+
+        PiTableEntry.Builder tableEntryBuilder = PiTableEntry.builder();
+
+        // In BMv2 0 is the highest priority.
+        // FIXME: Check P4Runtime and agree on maximum priority in the TableEntry javadoc.
+        // int newPriority = Integer.MAX_VALUE - rule.priority();
+
+        tableEntryBuilder
+                .forTable(piTableId)
+                .withPriority(rule.priority())
+                .withFieldMatches(fieldMatches)
+                .withAction(piAction);
+
+        if (!rule.isPermanent()) {
+            if (table.supportsAging()) {
+                tableEntryBuilder.withTimeout((double) rule.timeout());
+            } else {
+                log.warn("Flow rule is temporary, but table '{}' doesn't support " +
+                                 "aging, translating to permanent.", table.name());
+            }
+
+        }
+
+        return tableEntryBuilder.build();
+    }
+
+    /**
+     * Builds a PI action out of the given treatment, optionally using the given interpreter.
+     */
+    private static PiAction buildAction(TrafficTreatment treatment, PiPipelineInterpreter interpreter,
+                                        PiPipeconf pipeconf)
+            throws PiFlowRuleTranslationException {
+
+        PiTableAction piTableAction = null;
+
+        // If treatment has only one instruction of type PiInstruction, use that.
+        for (Instruction inst : treatment.allInstructions()) {
+            if (inst.type() == Instruction.Type.PROTOCOL_INDEPENDENT) {
+                if (treatment.allInstructions().size() == 1) {
+                    piTableAction = ((PiInstruction) inst).action();
+                } else {
+                    throw new PiFlowRuleTranslationException(format(
+                            "Unable to translate treatment, found multiple instructions " +
+                                    "of which one is protocol-independent: %s", treatment));
+                }
+            }
+        }
+
+        if (piTableAction == null && interpreter != null) {
+            // No PiInstruction, use interpreter to build action.
+            try {
+                piTableAction = interpreter.mapTreatment(treatment, pipeconf);
+            } catch (PiPipelineInterpreter.PiInterpreterException e) {
+                throw new PiFlowRuleTranslationException(
+                        "Interpreter was unable to translate treatment. " + e.getMessage());
+            }
+        }
+
+        if (piTableAction == null) {
+            // No PiInstruction, no interpreter. It's time to give up.
+            throw new PiFlowRuleTranslationException(
+                    "Unable to translate treatment, neither an interpreter or a "
+                            + "protocol-independent instruction were provided.");
+        }
+
+        if (piTableAction.type() != PiTableAction.Type.ACTION) {
+            // TODO: implement handling of other table action types, e.g. action profiles.
+            throw new PiFlowRuleTranslationException(format(
+                    "PiTableAction type %s is not supported yet.", piTableAction.type()));
+        }
+
+        return (PiAction) piTableAction;
+    }
+
+    /**
+     * Checks that the given PI action is suitable for the given table model and returns a new action instance with
+     * parameters well-sized, according to the table model. If not suitable, throws an exception explaining why.
+     */
+    private static PiAction typeCheckAction(PiAction piAction, PiTableModel table)
+            throws PiFlowRuleTranslationException {
+
+        // Table supports this action?
+        PiActionModel actionModel = table.action(piAction.id().name()).orElseThrow(
+                () -> new PiFlowRuleTranslationException(format("Not such action '%s' for table '%s'",
+                                                                piAction.id(), table.name())));
+
+        // Is the number of runtime parameters correct?
+        if (actionModel.params().size() != piAction.parameters().size()) {
+            throw new PiFlowRuleTranslationException(format(
+                    "Wrong number of runtime parameters for action '%s', expected %d but found %d",
+                    actionModel.name(), actionModel.params().size(), piAction.parameters().size()));
+        }
+
+        // Forge a new action instance with well-sized parameters.
+        // The same comment as in typeCheckFieldMatch() about duplicating field match instances applies here.
+        PiAction.Builder newActionBuilder = PiAction.builder().withId(piAction.id());
+        for (PiActionParam param : piAction.parameters()) {
+            PiActionParamModel paramModel = actionModel.param(param.id().name())
+                    .orElseThrow(() -> new PiFlowRuleTranslationException(format(
+                            "Not such parameter '%s' for action '%s'", param.id(), actionModel.name())));
+            try {
+                newActionBuilder.withParameter(new PiActionParam(param.id(),
+                                                                 fit(param.value(), paramModel.bitWidth())));
+            } catch (ByteSequenceTrimException e) {
+                throw new PiFlowRuleTranslationException(format(
+                        "Size mismatch for parameter '%s' of action '%s': %s",
+                        param.id(), piAction.id(), e.getMessage()));
+            }
+        }
+
+        return newActionBuilder.build();
+    }
+
+    /**
+     * Builds a collection of PI field matches out of the given selector, optionally using the given interpreter. The
+     * field matches returned are guaranteed to be compatible for the given table model.
+     */
+    private static Collection<PiFieldMatch> buildFieldMatches(PiPipelineInterpreter interpreter,
+                                                              TrafficSelector selector, PiTableModel tableModel)
+            throws PiFlowRuleTranslationException {
+
+        Map<PiHeaderFieldId, PiFieldMatch> fieldMatches = Maps.newHashMap();
+
+        // If present, find a PiCriterion and get its field matches as a map. Otherwise, use an empty map.
+        Map<PiHeaderFieldId, PiFieldMatch> piCriterionFields = selector.criteria().stream()
+                .filter(c -> c.type().equals(PROTOCOL_INDEPENDENT))
+                .map(c -> (PiCriterion) c)
+                .findFirst()
+                .map(PiCriterion::fieldMatches)
+                .map(c -> {
+                    Map<PiHeaderFieldId, PiFieldMatch> fieldMap = Maps.newHashMap();
+                    c.forEach(fieldMatch -> fieldMap.put(fieldMatch.fieldId(), fieldMatch));
+                    return fieldMap;
+                })
+                .orElse(Maps.newHashMap());
+
+        Set<Criterion> translatedCriteria = Sets.newHashSet();
+        Set<Criterion> ignoredCriteria = Sets.newHashSet();
+        Set<PiHeaderFieldId> usedPiCriterionFields = Sets.newHashSet();
+        Set<PiHeaderFieldId> ignoredPiCriterionFields = Sets.newHashSet();
+
+        for (PiTableMatchFieldModel fieldModel : tableModel.matchFields()) {
+
+            PiHeaderFieldId fieldId = PiHeaderFieldId.of(fieldModel.field().header().type().name(),
+                                                         fieldModel.field().type().name(),
+                                                         fieldModel.field().header().index());
+
+            int bitWidth = fieldModel.field().type().bitWidth();
+            int fieldByteWidth = (int) Math.ceil((double) bitWidth / 8);
+
+            Optional<Criterion.Type> criterionType =
+                    interpreter == null
+                            ? Optional.empty()
+                            : interpreter.mapPiHeaderFieldId(fieldId);
+
+            Criterion criterion = criterionType.map(selector::getCriterion).orElse(null);
+
+            if (!piCriterionFields.containsKey(fieldId) && criterion == null) {
+                // Neither a field in PiCriterion is available nor a Criterion mapping is possible.
+                // Can ignore if the match is ternary or LPM.
+                switch (fieldModel.matchType()) {
+                    case TERNARY:
+                        // Wildcard the whole field.
+                        fieldMatches.put(fieldId, new PiTernaryFieldMatch(
+                                fieldId,
+                                ImmutableByteSequence.ofZeros(fieldByteWidth),
+                                ImmutableByteSequence.ofZeros(fieldByteWidth)));
+                        break;
+                    case LPM:
+                        // LPM with prefix 0
+                        fieldMatches.put(fieldId, new PiLpmFieldMatch(fieldId,
+                                                                      ImmutableByteSequence.ofZeros(fieldByteWidth),
+                                                                      0));
+                        break;
+                    // FIXME: Can we handle the case of RANGE or VALID match?
+                    default:
+                        throw new PiFlowRuleTranslationException(format(
+                                "No value found for required match field '%s'", fieldId));
+                }
+                // Next field.
+                continue;
+            }
+
+            PiFieldMatch fieldMatch = null;
+
+            if (criterion != null) {
+                // Criterion mapping is possible for this field id.
+                try {
+                    fieldMatch = translateCriterion(criterion, fieldId, fieldModel.matchType(), bitWidth);
+                    translatedCriteria.add(criterion);
+                } catch (PiFlowRuleTranslationException ex) {
+                    // Ignore exception if the same field was found in PiCriterion.
+                    if (piCriterionFields.containsKey(fieldId)) {
+                        ignoredCriteria.add(criterion);
+                    } else {
+                        throw ex;
+                    }
+                }
+            }
+
+            if (piCriterionFields.containsKey(fieldId)) {
+                // Field was found in PiCriterion.
+                if (fieldMatch != null) {
+                    // Field was already translated from other criterion.
+                    // Throw exception only if we are trying to match on different values of the same field...
+                    if (!fieldMatch.equals(piCriterionFields.get(fieldId))) {
+                        throw new PiFlowRuleTranslationException(format(
+                                "Duplicate match field '%s': instance translated from criterion '%s' is different to " +
+                                        "what found in PiCriterion.", fieldId, criterion.type()));
+                    }
+                    ignoredPiCriterionFields.add(fieldId);
+                } else {
+                    fieldMatch = piCriterionFields.get(fieldId);
+                    fieldMatch = typeCheckFieldMatch(fieldMatch, fieldModel);
+                    usedPiCriterionFields.add(fieldId);
+                }
+            }
+
+            fieldMatches.put(fieldId, fieldMatch);
+        }
+
+        // Check if all criteria have been translated.
+        StringJoiner skippedCriteriaJoiner = new StringJoiner(", ");
+        selector.criteria().stream()
+                .filter(c -> !c.type().equals(PROTOCOL_INDEPENDENT))
+                .filter(c -> !translatedCriteria.contains(c) && !ignoredCriteria.contains(c))
+                .forEach(c -> skippedCriteriaJoiner.add(c.type().name()));
+        if (skippedCriteriaJoiner.length() > 0) {
+            throw new PiFlowRuleTranslationException(format(
+                    "The following criteria cannot be translated for table '%s': %s",
+                    tableModel.name(), skippedCriteriaJoiner.toString()));
+        }
+
+        // Check if all fields found in PiCriterion have been used.
+        StringJoiner skippedPiFieldsJoiner = new StringJoiner(", ");
+        piCriterionFields.keySet().stream()
+                .filter(k -> !usedPiCriterionFields.contains(k) && !ignoredPiCriterionFields.contains(k))
+                .forEach(k -> skippedPiFieldsJoiner.add(k.id()));
+        if (skippedPiFieldsJoiner.length() > 0) {
+            throw new PiFlowRuleTranslationException(format(
+                    "The following PiCriterion field matches are not supported in table '%s': %s",
+                    tableModel.name(), skippedPiFieldsJoiner.toString()));
+        }
+
+        return fieldMatches.values();
+    }
+
+    private static PiFieldMatch typeCheckFieldMatch(PiFieldMatch fieldMatch, PiTableMatchFieldModel fieldModel)
+            throws PiFlowRuleTranslationException {
+
+        // Check parameter type and size
+        if (!fieldModel.matchType().equals(fieldMatch.type())) {
+            throw new PiFlowRuleTranslationException(format(
+                    "Wrong match type for field '%s', expected %s, but found %s",
+                    fieldMatch.fieldId(), fieldModel.matchType().name(), fieldMatch.type().name()));
+        }
+
+        int modelBitWidth = fieldModel.field().type().bitWidth();
+
+        /*
+        Here we try to be robust against wrong size fields with the goal of having PiCriterion independent of the
+        pipeline model. We duplicate the field match, fitting the byte sequences to the bit-width specified in the
+        model. This operation is expensive when performed for each field match of each flow rule, but should be
+        mitigated by the translation cache provided by PiFlowRuleTranslationServiceImpl.
+        */
+
+        try {
+            switch (fieldModel.matchType()) {
+                case EXACT:
+                    return new PiExactFieldMatch(fieldMatch.fieldId(),
+                                                 fit(((PiExactFieldMatch) fieldMatch).value(), modelBitWidth));
+                case TERNARY:
+                    return new PiTernaryFieldMatch(fieldMatch.fieldId(),
+                                                   fit(((PiTernaryFieldMatch) fieldMatch).value(), modelBitWidth),
+                                                   fit(((PiTernaryFieldMatch) fieldMatch).mask(), modelBitWidth));
+                case LPM:
+                    PiLpmFieldMatch lpmfield = (PiLpmFieldMatch) fieldMatch;
+                    if (lpmfield.prefixLength() > modelBitWidth) {
+                        throw new PiFlowRuleTranslationException(format(
+                                "Invalid prefix length for LPM field '%s', found %d but field has bit-width %d",
+                                fieldMatch.fieldId(), lpmfield.prefixLength(), modelBitWidth));
+                    }
+                    return new PiLpmFieldMatch(fieldMatch.fieldId(),
+                                               fit(lpmfield.value(), modelBitWidth),
+                                               lpmfield.prefixLength());
+                case RANGE:
+                    return new PiRangeFieldMatch(fieldMatch.fieldId(),
+                                                 fit(((PiRangeFieldMatch) fieldMatch).lowValue(), modelBitWidth),
+                                                 fit(((PiRangeFieldMatch) fieldMatch).highValue(), modelBitWidth));
+                case VALID:
+                    return fieldMatch;
+                default:
+                    // Should never be here.
+                    throw new RuntimeException(
+                            "Unrecognized match type " + fieldModel.matchType().name());
+            }
+        } catch (ByteSequenceTrimException e) {
+            throw new PiFlowRuleTranslationException(format(
+                    "Size mismatch for field %s: %s", fieldMatch.fieldId(), e.getMessage()));
+        }
+    }
+}
diff --git a/core/net/src/main/java/org/onosproject/net/pi/impl/package-info.java b/core/net/src/main/java/org/onosproject/net/pi/impl/package-info.java
new file mode 100644
index 0000000..16e053a
--- /dev/null
+++ b/core/net/src/main/java/org/onosproject/net/pi/impl/package-info.java
@@ -0,0 +1,20 @@
+/*
+ * Copyright 2017-present 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.
+ */
+
+/**
+ * Core subsystem for handling protocol-independence.
+ */
+package org.onosproject.net.pi.impl;
\ No newline at end of file