adding constaints to intent API
diff --git a/core/api/src/main/java/org/onlab/onos/net/intent/ConnectivityIntent.java b/core/api/src/main/java/org/onlab/onos/net/intent/ConnectivityIntent.java
index 65d48d5..6f1f71e 100644
--- a/core/api/src/main/java/org/onlab/onos/net/intent/ConnectivityIntent.java
+++ b/core/api/src/main/java/org/onlab/onos/net/intent/ConnectivityIntent.java
@@ -23,6 +23,7 @@
 import org.onlab.onos.net.flow.TrafficTreatment;
 
 import java.util.Collection;
+import java.util.List;
 
 import static com.google.common.base.Preconditions.checkNotNull;
 
@@ -40,10 +41,14 @@
 
     private final TrafficSelector selector;
     private final TrafficTreatment treatment;
+    private final List<Constraint> constraints;
 
     /**
      * Creates a connectivity intent that matches on the specified selector
      * and applies the specified treatment.
+     * <p>
+     * Path will be chosen without any constraints.
+     * </p>
      *
      * @param id        intent identifier
      * @param appId     application identifier
@@ -56,9 +61,33 @@
                                  Collection<NetworkResource> resources,
                                  TrafficSelector selector,
                                  TrafficTreatment treatment) {
+        this(id, appId, resources, selector, treatment, null);
+    }
+
+    /**
+     * Creates a connectivity intent that matches on the specified selector
+     * and applies the specified treatment.
+     * <p>
+     * Path will be optimized based on the first constraint if one is given.
+     * </p>
+     *
+     * @param id          intent identifier
+     * @param appId       application identifier
+     * @param resources   required network resources (optional)
+     * @param selector    traffic selector
+     * @param treatment   treatment
+     * @param constraints optional prioritized list of constraints
+     * @throws NullPointerException if the selector or treatement is null
+     */
+    protected ConnectivityIntent(IntentId id, ApplicationId appId,
+                                 Collection<NetworkResource> resources,
+                                 TrafficSelector selector,
+                                 TrafficTreatment treatment,
+                                 List<Constraint> constraints) {
         super(id, appId, resources);
         this.selector = checkNotNull(selector);
         this.treatment = checkNotNull(treatment);
+        this.constraints = constraints;
     }
 
     /**
@@ -68,6 +97,7 @@
         super();
         this.selector = null;
         this.treatment = null;
+        this.constraints = null;
     }
 
     /**
@@ -89,13 +119,22 @@
     }
 
     /**
+     * Returns the set of connectivity constraints.
+     *
+     * @return list of intent constraints
+     */
+    public List<Constraint> constraints() {
+        return constraints;
+    }
+
+    /**
      * Produces a collection of network resources from the given links.
      *
      * @param links collection of links
      * @return collection of link resources
      */
     protected static Collection<NetworkResource> resources(Collection<Link> links) {
-        return ImmutableSet.<NetworkResource>copyOf(links);
+        return ImmutableSet.<NetworkResource>copyOf((Iterable<? extends NetworkResource>) links);
     }
 
 }
diff --git a/core/api/src/main/java/org/onlab/onos/net/intent/Constraint.java b/core/api/src/main/java/org/onlab/onos/net/intent/Constraint.java
new file mode 100644
index 0000000..9004aa6
--- /dev/null
+++ b/core/api/src/main/java/org/onlab/onos/net/intent/Constraint.java
@@ -0,0 +1,51 @@
+/*
+ * Copyright 2014 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.onlab.onos.net.intent;
+
+import org.onlab.onos.net.Link;
+import org.onlab.onos.net.Path;
+import org.onlab.onos.net.resource.LinkResourceService;
+
+/**
+ * Representation of a connectivity constraint capable of evaluating a link
+ * and determining the cost of traversing that link in the context of this
+ * constraint.
+ */
+public interface Constraint {
+
+    // TODO: Consider separating cost vs viability.
+
+    /**
+     * Evaluates the specified link and provides the cost for its traversal.
+     *
+     * @param link            link to be evaluated
+     * @param resourceService resource service for validating availability of
+     *                        link resources
+     * @return cost of link traversal
+     */
+    double cost(Link link, LinkResourceService resourceService);
+
+    /**
+     * Validates that the specified path satisfies the constraint.
+     *
+     * @param path            path to be validated
+     * @param resourceService resource service for validating availability of
+     *                        link resources
+     * @return cost of link traversal
+     */
+    boolean validate(Path path, LinkResourceService resourceService);
+
+}
diff --git a/core/api/src/main/java/org/onlab/onos/net/intent/HostToHostIntent.java b/core/api/src/main/java/org/onlab/onos/net/intent/HostToHostIntent.java
index 376a122..3fad93d 100644
--- a/core/api/src/main/java/org/onlab/onos/net/intent/HostToHostIntent.java
+++ b/core/api/src/main/java/org/onlab/onos/net/intent/HostToHostIntent.java
@@ -21,6 +21,8 @@
 import org.onlab.onos.net.flow.TrafficSelector;
 import org.onlab.onos.net.flow.TrafficTreatment;
 
+import java.util.List;
+
 import static com.google.common.base.Preconditions.checkNotNull;
 
 /**
@@ -44,11 +46,30 @@
     public HostToHostIntent(ApplicationId appId, HostId one, HostId two,
                             TrafficSelector selector,
                             TrafficTreatment treatment) {
+        this(appId, one, two, selector, treatment, null);
+    }
+
+    /**
+     * Creates a new host-to-host intent with the supplied host pair.
+     *
+     * @param appId       application identifier
+     * @param one         first host
+     * @param two         second host
+     * @param selector    action
+     * @param treatment   ingress port
+     * @param constraints optional prioritized list of path selection constraints
+     * @throws NullPointerException if {@code one} or {@code two} is null.
+     */
+    public HostToHostIntent(ApplicationId appId, HostId one, HostId two,
+                            TrafficSelector selector,
+                            TrafficTreatment treatment,
+                            List<Constraint> constraints) {
         super(id(HostToHostIntent.class, min(one, two), max(one, two),
-                 selector, treatment),
-              appId, null, selector, treatment);
+                 selector, treatment, constraints),
+              appId, null, selector, treatment, constraints);
         this.one = checkNotNull(one);
         this.two = checkNotNull(two);
+
     }
 
     private static HostId min(HostId one, HostId two) {
diff --git a/core/api/src/main/java/org/onlab/onos/net/intent/IntentId.java b/core/api/src/main/java/org/onlab/onos/net/intent/IntentId.java
index 8c75397..c4c2752 100644
--- a/core/api/src/main/java/org/onlab/onos/net/intent/IntentId.java
+++ b/core/api/src/main/java/org/onlab/onos/net/intent/IntentId.java
@@ -51,6 +51,15 @@
         this.fingerprint = fingerprint;
     }
 
+    /**
+     * Returns the backing fingerprint.
+     *
+     * @return the fingerprint
+     */
+    public long fingerprint() {
+        return fingerprint;
+    }
+
     @Override
     public int hashCode() {
         return (int) (fingerprint ^ (fingerprint >>> 32));
diff --git a/core/api/src/main/java/org/onlab/onos/net/intent/PathIntent.java b/core/api/src/main/java/org/onlab/onos/net/intent/PathIntent.java
index 0e9fa6d..9189bae 100644
--- a/core/api/src/main/java/org/onlab/onos/net/intent/PathIntent.java
+++ b/core/api/src/main/java/org/onlab/onos/net/intent/PathIntent.java
@@ -15,16 +15,11 @@
  */
 package org.onlab.onos.net.intent;
 
-import java.util.List;
-
 import com.google.common.base.MoreObjects;
-import com.google.common.collect.ImmutableList;
-
 import org.onlab.onos.core.ApplicationId;
 import org.onlab.onos.net.Path;
 import org.onlab.onos.net.flow.TrafficSelector;
 import org.onlab.onos.net.flow.TrafficTreatment;
-import org.onlab.onos.net.resource.LinkResourceRequest;
 
 /**
  * Abstraction of explicitly path specified connectivity intent.
@@ -32,7 +27,6 @@
 public class PathIntent extends ConnectivityIntent {
 
     private final Path path;
-    private final List<LinkResourceRequest> resourceRequests;
 
     /**
      * Creates a new point-to-point intent with the supplied ingress/egress
@@ -42,15 +36,13 @@
      * @param selector  traffic selector
      * @param treatment treatment
      * @param path      traversed links
-     * @param resourceRequests link resource request
      * @throws NullPointerException {@code path} is null
      */
     public PathIntent(ApplicationId appId, TrafficSelector selector,
-                      TrafficTreatment treatment, Path path, LinkResourceRequest[] resourceRequests) {
+                      TrafficTreatment treatment, Path path) {
         super(id(PathIntent.class, selector, treatment, path), appId,
               resources(path.links()), selector, treatment);
         this.path = path;
-        this.resourceRequests = ImmutableList.copyOf(resourceRequests);
     }
 
     /**
@@ -59,7 +51,6 @@
     protected PathIntent() {
         super();
         this.path = null;
-        this.resourceRequests = ImmutableList.of();
     }
 
     /**
@@ -76,10 +67,6 @@
         return true;
     }
 
-    // TODO: consider changing return type
-    public LinkResourceRequest[] resourceRequests() {
-        return resourceRequests.toArray(new LinkResourceRequest[resourceRequests.size()]);
-    }
 
     @Override
     public String toString() {
diff --git a/core/api/src/main/java/org/onlab/onos/net/intent/PointToPointIntent.java b/core/api/src/main/java/org/onlab/onos/net/intent/PointToPointIntent.java
index 61a1a56..e480ee2 100644
--- a/core/api/src/main/java/org/onlab/onos/net/intent/PointToPointIntent.java
+++ b/core/api/src/main/java/org/onlab/onos/net/intent/PointToPointIntent.java
@@ -16,10 +16,15 @@
 package org.onlab.onos.net.intent;
 
 import com.google.common.base.MoreObjects;
+import com.google.common.collect.ImmutableList;
 import org.onlab.onos.core.ApplicationId;
 import org.onlab.onos.net.ConnectPoint;
+import org.onlab.onos.net.Link;
 import org.onlab.onos.net.flow.TrafficSelector;
 import org.onlab.onos.net.flow.TrafficTreatment;
+import org.onlab.onos.net.intent.constraint.LinkTypeConstraint;
+
+import java.util.List;
 
 import static com.google.common.base.Preconditions.checkNotNull;
 
@@ -33,7 +38,7 @@
 
     /**
      * Creates a new point-to-point intent with the supplied ingress/egress
-     * ports.
+     * ports and with built-in link type constraint to avoid optical links.
      *
      * @param appId        application identifier
      * @param selector     traffic selector
@@ -46,8 +51,30 @@
                               TrafficTreatment treatment,
                               ConnectPoint ingressPoint,
                               ConnectPoint egressPoint) {
-        super(id(PointToPointIntent.class, selector, treatment, ingressPoint, egressPoint),
-              appId, null, selector, treatment);
+        this(appId, selector, treatment, ingressPoint, egressPoint,
+             ImmutableList.of(new LinkTypeConstraint(false, Link.Type.OPTICAL)));
+    }
+
+    /**
+     * Creates a new point-to-point intent with the supplied ingress/egress
+     * ports and constraints.
+     *
+     * @param appId        application identifier
+     * @param selector     traffic selector
+     * @param treatment    treatment
+     * @param ingressPoint ingress port
+     * @param egressPoint  egress port
+     * @param constraints  optional list of constraints
+     * @throws NullPointerException if {@code ingressPoint} or {@code egressPoints} is null.
+     */
+    public PointToPointIntent(ApplicationId appId, TrafficSelector selector,
+                              TrafficTreatment treatment,
+                              ConnectPoint ingressPoint,
+                              ConnectPoint egressPoint,
+                              List<Constraint> constraints) {
+        super(id(PointToPointIntent.class, selector, treatment,
+                 ingressPoint, egressPoint, constraints),
+              appId, null, selector, treatment, constraints);
         this.ingressPoint = checkNotNull(ingressPoint);
         this.egressPoint = checkNotNull(egressPoint);
     }
@@ -89,6 +116,7 @@
                 .add("treatment", treatment())
                 .add("ingress", ingressPoint)
                 .add("egress", egressPoint)
+                .add("constraints", constraints())
                 .toString();
     }
 
diff --git a/core/api/src/main/java/org/onlab/onos/net/intent/PointToPointIntentWithBandwidthConstraint.java b/core/api/src/main/java/org/onlab/onos/net/intent/PointToPointIntentWithBandwidthConstraint.java
deleted file mode 100644
index a9b614c..0000000
--- a/core/api/src/main/java/org/onlab/onos/net/intent/PointToPointIntentWithBandwidthConstraint.java
+++ /dev/null
@@ -1,111 +0,0 @@
-/*
- * Licensed to the Apache Software Foundation (ASF) under one
- * or more contributor license agreements.  See the NOTICE file
- * distributed with this work for additional information
- * regarding copyright ownership.  The ASF licenses this file
- * to you 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.onlab.onos.net.intent;
-
-import org.onlab.onos.core.ApplicationId;
-import org.onlab.onos.net.ConnectPoint;
-import org.onlab.onos.net.flow.TrafficSelector;
-import org.onlab.onos.net.flow.TrafficTreatment;
-import org.onlab.onos.net.resource.BandwidthResourceRequest;
-
-import com.google.common.base.MoreObjects;
-
-import static com.google.common.base.Preconditions.checkNotNull;
-
-/**
- * Abstraction of point-to-point connectivity.
- */
-public class PointToPointIntentWithBandwidthConstraint extends ConnectivityIntent {
-
-    private final ConnectPoint ingressPoint;
-    private final ConnectPoint egressPoint;
-    private final BandwidthResourceRequest bandwidthResourceRequest;
-
-    /**
-     * Creates a new point-to-point intent with the supplied ingress/egress
-     * ports.
-     *
-     * @param appId        application identifier
-     * @param selector     traffic selector
-     * @param treatment    treatment
-     * @param ingressPoint ingress port
-     * @param egressPoint  egress port
-     * @param bandwidthResourceRequest bandwidth resource request
-     * @throws NullPointerException if {@code ingressPoint} or {@code egressPoints} is null.
-     */
-    public PointToPointIntentWithBandwidthConstraint(ApplicationId appId, TrafficSelector selector,
-                                                     TrafficTreatment treatment,
-                                                     ConnectPoint ingressPoint,
-                                                     ConnectPoint egressPoint,
-                                                     BandwidthResourceRequest bandwidthResourceRequest) {
-        super(id(PointToPointIntentWithBandwidthConstraint.class, selector,
-                 treatment, ingressPoint, egressPoint, bandwidthResourceRequest.bandwidth()),
-              appId, null, selector, treatment);
-        this.ingressPoint = checkNotNull(ingressPoint);
-        this.egressPoint = checkNotNull(egressPoint);
-        this.bandwidthResourceRequest = bandwidthResourceRequest;
-    }
-
-    /**
-     * Constructor for serializer.
-     */
-    protected PointToPointIntentWithBandwidthConstraint() {
-        super();
-        this.ingressPoint = null;
-        this.egressPoint = null;
-        bandwidthResourceRequest = new BandwidthResourceRequest(0.0);
-    }
-
-    /**
-     * Returns the port on which the ingress traffic should be connected to
-     * the egress.
-     *
-     * @return ingress port
-     */
-    public ConnectPoint ingressPoint() {
-        return ingressPoint;
-    }
-
-    /**
-     * Returns the port on which the traffic should egress.
-     *
-     * @return egress port
-     */
-    public ConnectPoint egressPoint() {
-        return egressPoint;
-    }
-
-    public BandwidthResourceRequest bandwidthRequest() {
-        return this.bandwidthResourceRequest;
-    }
-
-    @Override
-    public String toString() {
-        return MoreObjects.toStringHelper(getClass())
-                .add("id", id())
-                .add("appId", appId())
-                .add("selector", selector())
-                .add("treatment", treatment())
-                .add("ingress", ingressPoint)
-                .add("egress", egressPoint)
-                .add("bandwidth", bandwidthResourceRequest.bandwidth().toString())
-                .toString();
-    }
-
-}
diff --git a/core/api/src/main/java/org/onlab/onos/net/intent/constraint/BandwidthConstraint.java b/core/api/src/main/java/org/onlab/onos/net/intent/constraint/BandwidthConstraint.java
new file mode 100644
index 0000000..44d6875
--- /dev/null
+++ b/core/api/src/main/java/org/onlab/onos/net/intent/constraint/BandwidthConstraint.java
@@ -0,0 +1,89 @@
+/*
+ * Copyright 2014 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.onlab.onos.net.intent.constraint;
+
+import org.onlab.onos.net.Link;
+import org.onlab.onos.net.resource.Bandwidth;
+import org.onlab.onos.net.resource.BandwidthResourceRequest;
+import org.onlab.onos.net.resource.LinkResourceService;
+import org.onlab.onos.net.resource.ResourceRequest;
+import org.onlab.onos.net.resource.ResourceType;
+
+import java.util.Objects;
+
+import static com.google.common.base.MoreObjects.toStringHelper;
+import static com.google.common.base.Preconditions.checkNotNull;
+
+/**
+ * Constraint that evaluates links based on available bandwidths.
+ */
+public class BandwidthConstraint extends BooleanConstraint {
+
+    private final Bandwidth bandwidth;
+
+    /**
+     * Creates a new bandwidth constraint.
+     *
+     * @param bandwidth required bandwidth
+     */
+    public BandwidthConstraint(Bandwidth bandwidth) {
+        this.bandwidth = checkNotNull(bandwidth, "Bandwidth cannot be null");
+    }
+
+    @Override
+    public boolean isValid(Link link, LinkResourceService resourceService) {
+        for (ResourceRequest request : resourceService.getAvailableResources(link)) {
+            if (request.type() == ResourceType.BANDWIDTH) {
+                BandwidthResourceRequest brr = (BandwidthResourceRequest) request;
+                if (brr.bandwidth().toDouble() >= bandwidth.toDouble()) {
+                    return true;
+                }
+            }
+        }
+        return false;
+    }
+
+    /**
+     * Returns the bandwidth required by this constraint.
+     *
+     * @return required bandwidth
+     */
+    public Bandwidth bandwidth() {
+        return bandwidth;
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(bandwidth);
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) {
+            return true;
+        }
+        if (obj == null || getClass() != obj.getClass()) {
+            return false;
+        }
+        final BandwidthConstraint other = (BandwidthConstraint) obj;
+        return Objects.equals(this.bandwidth, other.bandwidth);
+    }
+
+    @Override
+    public String toString() {
+        return toStringHelper(this).add("bandwidth", bandwidth).toString();
+    }
+}
diff --git a/core/api/src/main/java/org/onlab/onos/net/intent/constraint/BooleanConstraint.java b/core/api/src/main/java/org/onlab/onos/net/intent/constraint/BooleanConstraint.java
new file mode 100644
index 0000000..9ad4ac7
--- /dev/null
+++ b/core/api/src/main/java/org/onlab/onos/net/intent/constraint/BooleanConstraint.java
@@ -0,0 +1,53 @@
+/*
+ * Copyright 2014 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.onlab.onos.net.intent.constraint;
+
+import org.onlab.onos.net.Link;
+import org.onlab.onos.net.Path;
+import org.onlab.onos.net.intent.Constraint;
+import org.onlab.onos.net.resource.LinkResourceService;
+
+/**
+ * Abstract base class for various constraints that evaluate link viability
+ * in a yes/no fashion.
+ */
+public abstract class BooleanConstraint implements Constraint {
+
+    /**
+     * Returns true if the specified link satisfies the constraint.
+     *
+     * @param link            link to be validated
+     * @param resourceService resource service for checking available link resources
+     * @return true if link is viable
+     */
+    public abstract boolean isValid(Link link, LinkResourceService resourceService);
+
+    @Override
+    public double cost(Link link, LinkResourceService resourceService) {
+        return isValid(link, resourceService) ? +1 : -1;
+    }
+
+    @Override
+    public boolean validate(Path path, LinkResourceService resourceService) {
+        for (Link link : path.links()) {
+            if (isValid(link, resourceService)) {
+                return false;
+            }
+        }
+        return true;
+    }
+
+}
diff --git a/core/api/src/main/java/org/onlab/onos/net/intent/constraint/LambdaConstraint.java b/core/api/src/main/java/org/onlab/onos/net/intent/constraint/LambdaConstraint.java
new file mode 100644
index 0000000..d1d33d6
--- /dev/null
+++ b/core/api/src/main/java/org/onlab/onos/net/intent/constraint/LambdaConstraint.java
@@ -0,0 +1,84 @@
+/*
+ * Copyright 2014 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.onlab.onos.net.intent.constraint;
+
+import org.onlab.onos.net.Link;
+import org.onlab.onos.net.resource.Lambda;
+import org.onlab.onos.net.resource.LinkResourceService;
+import org.onlab.onos.net.resource.ResourceRequest;
+import org.onlab.onos.net.resource.ResourceType;
+
+import java.util.Objects;
+
+import static com.google.common.base.MoreObjects.toStringHelper;
+
+/**
+ * Constraint that evaluates links based on available lambda.
+ */
+public class LambdaConstraint extends BooleanConstraint {
+
+    private final Lambda lambda;
+
+    /**
+     * Creates a new optical lambda constraint.
+     *
+     * @param lambda optional lambda to indicate a specific lambda
+     */
+    public LambdaConstraint(Lambda lambda) {
+        this.lambda = lambda;
+    }
+
+    @Override
+    public boolean isValid(Link link, LinkResourceService resourceService) {
+        for (ResourceRequest request : resourceService.getAvailableResources(link)) {
+            if (request.type() == ResourceType.LAMBDA) {
+                return true;
+            }
+        }
+        return false;
+    }
+
+    /**
+     * Returns the lambda required by this constraint.
+     *
+     * @return required lambda
+     */
+    public Lambda lambda() {
+        return lambda;
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(lambda);
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) {
+            return true;
+        }
+        if (obj == null || getClass() != obj.getClass()) {
+            return false;
+        }
+        final LambdaConstraint other = (LambdaConstraint) obj;
+        return Objects.equals(this.lambda, other.lambda);
+    }
+
+    @Override
+    public String toString() {
+        return toStringHelper(this).add("lambda", lambda).toString();
+    }
+}
diff --git a/core/api/src/main/java/org/onlab/onos/net/intent/constraint/LinkTypeConstraint.java b/core/api/src/main/java/org/onlab/onos/net/intent/constraint/LinkTypeConstraint.java
new file mode 100644
index 0000000..5640591
--- /dev/null
+++ b/core/api/src/main/java/org/onlab/onos/net/intent/constraint/LinkTypeConstraint.java
@@ -0,0 +1,100 @@
+/*
+ * Copyright 2014 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.onlab.onos.net.intent.constraint;
+
+import com.google.common.collect.ImmutableSet;
+import org.onlab.onos.net.Link;
+import org.onlab.onos.net.resource.LinkResourceService;
+
+import java.util.Objects;
+import java.util.Set;
+
+import static com.google.common.base.MoreObjects.toStringHelper;
+import static com.google.common.base.Preconditions.checkArgument;
+import static com.google.common.base.Preconditions.checkNotNull;
+
+/**
+ * Constraint that evaluates links based on their type.
+ */
+public class LinkTypeConstraint extends BooleanConstraint {
+
+    private final Set<Link.Type> types;
+    private final boolean isInclusive;
+
+    /**
+     * Creates a new constraint for requesting connectivity using or avoiding
+     * the specified link types.
+     *
+     * @param inclusive indicates whether the given link types are to be
+     *                  permitted or avoided
+     * @param types     link types
+     */
+    public LinkTypeConstraint(boolean inclusive, Link.Type... types) {
+        checkNotNull(types, "Link types cannot be null");
+        checkArgument(types.length > 0, "There must be more than one type");
+        this.types = ImmutableSet.copyOf(types);
+        this.isInclusive = inclusive;
+    }
+
+    @Override
+    public boolean isValid(Link link, LinkResourceService resourceService) {
+        boolean contains = types.contains(link.type());
+        return isInclusive ? contains : !contains;
+    }
+
+    /**
+     * Returns the set of link types.
+     *
+     * @return set of link types
+     */
+    public Set<Link.Type> types() {
+        return types;
+    }
+
+    /**
+     * Indicates if the constraint is inclusive or exclusive.
+     *
+     * @return true if inclusive
+     */
+    public boolean isInclusive() {
+        return isInclusive;
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(types, isInclusive);
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) {
+            return true;
+        }
+        if (obj == null || getClass() != obj.getClass()) {
+            return false;
+        }
+        final LinkTypeConstraint other = (LinkTypeConstraint) obj;
+        return Objects.equals(this.types, other.types) && Objects.equals(this.isInclusive, other.isInclusive);
+    }
+
+    @Override
+    public String toString() {
+        return toStringHelper(this)
+                .add("inclusive", isInclusive)
+                .add("types", types)
+                .toString();
+    }
+}
diff --git a/core/api/src/main/java/org/onlab/onos/net/resource/DefaultLinkResourceRequest.java b/core/api/src/main/java/org/onlab/onos/net/resource/DefaultLinkResourceRequest.java
index 73b48df6..c3f5c28 100644
--- a/core/api/src/main/java/org/onlab/onos/net/resource/DefaultLinkResourceRequest.java
+++ b/core/api/src/main/java/org/onlab/onos/net/resource/DefaultLinkResourceRequest.java
@@ -20,9 +20,12 @@
 import java.util.Set;
 
 import org.onlab.onos.net.Link;
+import org.onlab.onos.net.intent.Constraint;
 import org.onlab.onos.net.intent.IntentId;
 
 import com.google.common.collect.ImmutableSet;
+import org.onlab.onos.net.intent.constraint.BandwidthConstraint;
+import org.onlab.onos.net.intent.constraint.LambdaConstraint;
 
 /**
  * Implementation of {@link LinkResourceRequest}.
@@ -125,6 +128,18 @@
             return this;
         }
 
+        @Override
+        public LinkResourceRequest.Builder addConstraint(Constraint constraint) {
+            if (constraint instanceof LambdaConstraint) {
+                return addLambdaRequest();
+            } else if (constraint instanceof BandwidthConstraint) {
+                BandwidthConstraint bw = (BandwidthConstraint) constraint;
+                return addBandwidthRequest(bw.bandwidth().toDouble());
+            }
+            return this;
+        }
+
+
         /**
          * Returns link resource request.
          *
diff --git a/core/api/src/main/java/org/onlab/onos/net/resource/LinkResourceRequest.java b/core/api/src/main/java/org/onlab/onos/net/resource/LinkResourceRequest.java
index a511778..23a0c30 100644
--- a/core/api/src/main/java/org/onlab/onos/net/resource/LinkResourceRequest.java
+++ b/core/api/src/main/java/org/onlab/onos/net/resource/LinkResourceRequest.java
@@ -19,6 +19,7 @@
 import java.util.Set;
 
 import org.onlab.onos.net.Link;
+import org.onlab.onos.net.intent.Constraint;
 import org.onlab.onos.net.intent.IntentId;
 
 /**
@@ -67,6 +68,14 @@
         public Builder addBandwidthRequest(double bandwidth);
 
         /**
+         * Adds the resources required for a constraint.
+         *
+         * @param constraint the constraint
+         * @return self
+         */
+        public Builder addConstraint(Constraint constraint);
+
+        /**
          * Returns link resource request.
          *
          * @return link resource request