diff --git a/model/ccnx-face.h b/model/ccnx-face.h
index 35f7dc1..121c146 100644
--- a/model/ccnx-face.h
+++ b/model/ccnx-face.h
@@ -33,88 +33,116 @@
 class Node;
 
 /**
- * \brief The Ccnx representation of a network face
+ * \ingroup ccnx
+ * \brief Virtual class defining CCNx face
  *
- * This class roughly corresponds to the struct in_device
- * of Linux; the main purpose is to provide address-family
- * specific information (addresses) about an face.
+ * This class defines basic functionality of CCNx face. Face is core
+ * component responsible for actual delivery of data packet to and
+ * from CCNx stack
  *
- * By default, Ccnx face are created in the "down" state
- * no IP addresses.  Before becoming useable, the user must 
- * add an address of some type and invoke Setup on them.
+ * \see CcnxLocalFace, CcnxNetDeviceFace, CcnxIpv4Face, CcnxUdpFace
  */
 class CcnxFace  : public Object
 {
 public:
+  /**
+   * \brief Ccnx protocol hanler
+   *
+   * \param face Face from which packet has been received
+   * \param packet Received packet
+   */
+  typedef Callback<void,Ptr<CcnxFace>,Ptr<Packet> > ProtocolHandler;
+  
+  /**
+   * \brief Interface ID
+   *
+   * \return interface ID
+   */
   static TypeId GetTypeId (void);
 
+  /**
+   * \brief Default constructor
+   */
   CcnxFace ();
   virtual ~CcnxFace();
 
-  virtual void SetNode (Ptr<Node> node); 
-  virtual void SetDevice (Ptr<NetDevice> device);
-
+  ////////////////////////////////////////////////////////////////////
+  
   /**
-   * \returns the underlying NetDevice. This method cannot return zero.
-   */
-  virtual Ptr<NetDevice> GetDevice (void) const;
-
-  /**
-   * \param metric configured routing metric (cost) of this face
+   * \brief Register callback to call when new packet arrives on the face
    *
-   * Note:  This is synonymous to the Metric value that ifconfig prints
-   * out.  It is used by ns-3 global routing, but other routing daemons
-   * choose to ignore it. 
+   * This method should call protocol-dependent registration function
+   */
+  void RegisterProtocolHandler (ProtocolHandler handler) = 0;
+  
+  /**
+   * \brief Send packet on a face
+   *
+   * \param p smart pointer to a packet to send
+   */ 
+  virtual void Send (Ptr<Packet> p) = 0;
+
+  ////////////////////////////////////////////////////////////////////
+
+  /**
+   * \brief Associate Node object with face
+   *
+   * \param node smart pointer to a Node object
+   */
+  virtual void SetNode (Ptr<Node> node);
+
+  /**
+   * \brief Assign routing/forwarding metric with face
+   *
+   * \param metric configured routing metric (cost) of this face
    */
   virtual void SetMetric (uint16_t metric);
 
   /**
-   * \returns configured routing metric (cost) of this face
+   * \brief Get routing/forwarding metric assigned to the face
    *
-   * Note:  This is synonymous to the Metric value that ifconfig prints
-   * out.  It is used by ns-3 global routing, but other routing daemons 
-   * may choose to ignore it. 
+   * \returns configured routing/forwarding metric (cost) of this face
    */
   virtual uint16_t GetMetric (void) const;
 
   /**
-   * These are IP face states and may be distinct from 
-   * NetDevice states, such as found in real implementations
-   * (where the device may be down but IP face state is still up).
+   * These are face states and may be distinct from actual lower-layer
+   * device states, such as found in real implementations (where the
+   * device may be down but ccnx face state is still up).
    */
+  
   /**
-   * \returns true if this face is enabled, false otherwise.
+   * \brief Enable this face
    */
-  virtual bool IsUp (void) const;
+  virtual void SetUp ();
 
   /**
-   * \returns true if this face is disabled, false otherwise.
-   */
-  virtual bool IsDown (void) const;
-
-  /**
-   * Enable this face
-   */
-  virtual void SetUp (void);
-
-  /**
-   * Disable this face
+   * \brief Disable this face
    */
   virtual void SetDown (void);
 
   /**
-   * \param p packet to send
-   */ 
-  virtual void Send (Ptr<Packet> p);
+   * \brief Returns true if this face is enabled, false otherwise.
+   */
+  virtual bool IsUp () const;
+
+  /**
+   * \brief Returns true if this face is disabled, false otherwise.
+   */
+  virtual bool IsDown () const;
 
 protected:
   virtual void DoDispose (void);
 
 private:
+  CcnxFace (const CcnxFace &) {} ///< Disabled copy constructor
+  CcnxFace& operator= (const CcnxFace &) {} ///< Disabled copy operator
+  
+protected:
   bool m_ifup;
+  uint32_t m_id; ///< id of the interface in the CCNx stack (per-node uniqueness)
   uint16_t m_metric;
   Ptr<Node> m_node;
-  Ptr<NetDevice> m_device;
 };
 
 std::ostream& operator<< (std::ostream& os, CcnxFace const& face);
diff --git a/model/ccnx-l3-protocol.cc b/model/ccnx-l3-protocol.cc
index 2a13f4c..d698356 100644
--- a/model/ccnx-l3-protocol.cc
+++ b/model/ccnx-l3-protocol.cc
@@ -1,22 +1,22 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil -*- */
-//
-// Copyright (c) 2006 Georgia Tech Research Corporation
-//
-// This program is free software; you can redistribute it and/or modify
-// it under the terms of the GNU General Public License version 2 as
-// published by the Free Software Foundation;
-//
-// This program is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-// GNU General Public License for more details.
-//
-// You should have received a copy of the GNU General Public License
-// along with this program; if not, write to the Free Software
-// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
-//
-// Author: 
-//
+/*
+ * Copyright (c) 2011 University of California, Los Angeles
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation;
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ * Author: Alexander Afanasyev <alexander.afanasyev@ucla.edu>
+ */
 
 #include "ccnx-l3-protocol.h"
 
@@ -72,6 +72,7 @@
 }
 
 CcnxL3Protocol::CcnxL3Protocol()
+: m_faceCounter (0)
 {
   NS_LOG_FUNCTION (this);
 }
@@ -141,18 +142,19 @@
 {
   NS_LOG_FUNCTION (this << *face);
 
-  // Ptr<Node> node = GetObject<Node> (); ///< \todo not sure why this thing should be called...
   face->SetNode (m_node);
+  face->SetId (m_faceCounter); // sets a unique ID of the face. This ID serves only informational purposes
 
-  if (face->GetDevice() != 0)
-    {
-      m_node->RegisterProtocolHandler (MakeCallback (&CcnxL3Protocol::ReceiveFromLower, this), 
-                                       CcnxL3Protocol::ETHERNET_FRAME_TYPE, face->GetDevice(), true/*promiscuous mode*/);
-    }
+  face->RegisterProtocolHandler (MakeCallback (&CcnxL3Protocol::ReceiveFromLower, this));
+  // if (face->GetDevice() != 0)
+  //   {
+  //     m_node->RegisterProtocolHandler (MakeCallback (&CcnxL3Protocol::ReceiveFromLower, this), 
+  //                                      CcnxL3Protocol::ETHERNET_FRAME_TYPE, face->GetDevice(), true/*promiscuous mode*/);
+  //   }
 
-  uint32_t index = m_faces.size ();
   m_faces.push_back (face);
-  return index;
+  m_faceCounter ++;
+  return m_faceCounter;
 }
 
 
diff --git a/model/ccnx-l3-protocol.h b/model/ccnx-l3-protocol.h
index e8a0d22..28a8d06 100644
--- a/model/ccnx-l3-protocol.h
+++ b/model/ccnx-l3-protocol.h
@@ -104,7 +104,8 @@
   void SetForwardingStrategy (Ptr<CcnxForwardingStrategy> forwardingStrategy);
   Ptr<CcnxForwardingStrategy> GetForwardingStrategy (void) const;
 
-  virtual void Send (Ptr<Packet> packet, const Ptr<CcnxFace> &face);
+  virtual void Send (const Ptr<CcnxFace> &face, Ptr<Packet> packet);
+  virtual void ReceiveFromLower (const Ptr<Face> &device, Ptr<const Packet> p);
 
   virtual uint32_t AddFace (const Ptr<CcnxFace> &face);
   virtual uint32_t GetNFaces (void) const;
@@ -119,21 +120,6 @@
 
 protected:
   /**
-   * Lower layer calls this method after calling L3Demux::Lookup
-   *
-   * \param device network device
-   * \param p the packet
-   * \param protocol lower layer protocol value
-   * \param from lower layer address of the correspondant
-   * \param to lower layer address of the destination
-   * \param packetType type of the packet (broadcast/multicast/unicast/otherhost)
-   */
-  void ReceiveFromLower (Ptr<NetDevice> device, Ptr<const Packet> p, uint16_t protocol,
-                 const Address &from,
-                 const Address &to,
-                 NetDevice::PacketType packetType);
-
-  /**
    * Actual processing of incoming CCNx packets. Also processing packets coming from local apps
    * 
    * Processing Interest packets
@@ -175,6 +161,7 @@
   ReceiveAndProcess (Ptr<CcnxFace> face, Ptr<Header> header, Ptr<Packet> p);
 
 private:
+  uint32_t m_faceCounter; ///< counter of faces. Increased every time a new face is added to the stack
   typedef std::vector<Ptr<CcnxFace> > CcnxFaceList;
   CcnxFaceList m_faces;
 
diff --git a/model/ccnx.h b/model/ccnx.h
index c7627ab..3ec6058 100644
--- a/model/ccnx.h
+++ b/model/ccnx.h
@@ -109,13 +109,24 @@
   /**
    * \brief Send a packet to a specified face
    *
-   * \param packet fully prepared CCNx packet to send
    * \param face face where to send this packet
+   * \param packet fully prepared CCNx packet to send
    *
    * Higher-level layers (forwarding strategy in particular) call this
    * method to send a packet down the stack to the MAC and PHY layers.
    */
-  virtual void Send (Ptr<Packet> packet, const Ptr<CcnxFace> &face) = 0;
+  virtual void Send (const Ptr<CcnxFace> &face, Ptr<Packet> packet) = 0;
+
+  /**
+   * \brief Lower layers calls this method after demultiplexing
+   *
+   * Lower-layer-dependent implementation of CcnxFace will do actual work
+   * to set up demultiplexing and call this function as a callback
+   *
+   * \param face face from which packet came from
+   * \param p the packet
+   */
+  void ReceiveFromLower (const Ptr<Face> &device, Ptr<const Packet> p);
 
   /**
    * \param face The face number of an Ccnx interface.