Sketched out packet service and related abstractions.
diff --git a/cli/src/main/java/org/onlab/onos/cli/net/ClusterLinksCommand.java b/cli/src/main/java/org/onlab/onos/cli/net/ClusterLinksCommand.java
index 5285418..246c39e 100644
--- a/cli/src/main/java/org/onlab/onos/cli/net/ClusterLinksCommand.java
+++ b/cli/src/main/java/org/onlab/onos/cli/net/ClusterLinksCommand.java
@@ -16,7 +16,7 @@
 public class ClusterLinksCommand extends ClustersListCommand {
 
     @Argument(index = 0, name = "id", description = "Cluster ID",
-              required = false, multiValued = false)
+              required = true, multiValued = false)
     String id = null;
 
     @Override
@@ -30,5 +30,4 @@
         return null;
     }
 
-
 }
diff --git a/cli/src/main/java/org/onlab/onos/cli/net/LinksListCommand.java b/cli/src/main/java/org/onlab/onos/cli/net/LinksListCommand.java
index 6c3952d..e62fb05 100644
--- a/cli/src/main/java/org/onlab/onos/cli/net/LinksListCommand.java
+++ b/cli/src/main/java/org/onlab/onos/cli/net/LinksListCommand.java
@@ -33,10 +33,10 @@
     }
 
     /**
-     * Returns a formated string representing the gien link.
+     * Returns a formatted string representing the given link.
      *
      * @param link infrastructure link
-     * @return formated link string
+     * @return formatted link string
      */
     public static String linkString(Link link) {
         return String.format(FMT, link.src().deviceId(), link.src().port(),
diff --git a/cli/src/main/java/org/onlab/onos/cli/net/PathListCommand.java b/cli/src/main/java/org/onlab/onos/cli/net/PathListCommand.java
new file mode 100644
index 0000000..114d837
--- /dev/null
+++ b/cli/src/main/java/org/onlab/onos/cli/net/PathListCommand.java
@@ -0,0 +1,43 @@
+package org.onlab.onos.cli.net;
+
+import org.apache.karaf.shell.commands.Argument;
+import org.apache.karaf.shell.commands.Command;
+import org.onlab.onos.net.Path;
+
+import java.util.Set;
+
+import static org.onlab.onos.net.DeviceId.deviceId;
+
+/**
+ * Lists all shortest-paths paths between the specified source and
+ * destination devices.
+ */
+@Command(scope = "onos", name = "paths",
+         description = "Lists all shortest-paths paths between the specified source and destination devices")
+public class PathListCommand extends TopologyCommand {
+
+    private static final String FMT = "src=%s/%s, dst=%s/%s, type=%s";
+
+    @Argument(index = 0, name = "src", description = "Source device ID",
+              required = true, multiValued = false)
+    String src = null;
+
+    @Argument(index = 0, name = "dst", description = "Destination device ID",
+              required = true, multiValued = false)
+    String dst = null;
+
+    @Override
+    protected Object doExecute() throws Exception {
+        init();
+        Set<Path> paths = service.getPaths(topology, deviceId(src), deviceId(dst));
+        for (Path path : paths) {
+            print(pathString(path));
+        }
+        return null;
+    }
+
+    private String pathString(Path path) {
+        return path.toString();
+    }
+
+}
diff --git a/cli/src/main/java/org/onlab/onos/cli/net/TopologyCommand.java b/cli/src/main/java/org/onlab/onos/cli/net/TopologyCommand.java
index a390025..6c141ae 100644
--- a/cli/src/main/java/org/onlab/onos/cli/net/TopologyCommand.java
+++ b/cli/src/main/java/org/onlab/onos/cli/net/TopologyCommand.java
@@ -12,6 +12,7 @@
          description = "Lists summary of the current topology")
 public class TopologyCommand extends AbstractShellCommand {
 
+    // TODO: format the time-stamp
     private static final String FMT =
             "time=%s, devices=%d, links=%d, clusters=%d, paths=%d";