Cleaned up some of the host-related abstractions and filled in more of the host manager implementation.
diff --git a/core/api/src/main/java/org/onlab/onos/net/Host.java b/core/api/src/main/java/org/onlab/onos/net/Host.java
index 17eaf22..d66566d 100644
--- a/core/api/src/main/java/org/onlab/onos/net/Host.java
+++ b/core/api/src/main/java/org/onlab/onos/net/Host.java
@@ -1,12 +1,35 @@
 package org.onlab.onos.net;
 
+import org.onlab.packet.IPv4;
+import org.onlab.packet.MACAddress;
+
+import java.util.Set;
+
 /**
  * Abstraction of an end-station host on the network, essentially a NIC.
  */
 public interface Host extends Element {
 
-    // MAC, IP(s), optional VLAN ID
+    /**
+     * Host identification.
+     *
+     * @return host id
+     */
+    HostId id();
 
+    /**
+     * Returns the host MAC address.
+     *
+     * @return mac address
+     */
+    MACAddress mac();
+
+    /**
+     * Returns set of IP addresses currently bound to the host MAC address.
+     *
+     * @return set of IP addresses; empty if no IP address is bound
+     */
+    Set<IPv4> ipAddresses();
 
     /**
      * Returns the most recent host location where the host attaches to the
@@ -16,6 +39,6 @@
      */
     HostLocation location();
 
-    // list of recent locations?
+    // TODO: explore capturing list of recent locations to aid in mobility
 
 }