1 /*!

     2   \page net-device How to create a new OSI layer 1 + 2 implementation ?

     3   \anchor howtos-net-device

     4 

     5   <b>Question:</b> How do I integrate a new OSI layer 1 + 2 implementation ?

     6 

     7   <b>Answer:</b> The OSI layers 1 and 2 are represented by the ns3::NetDevice

     8   and ns3::Channel classes. To plug transparently in ns-3, a new layer 1+2 model

     9   thus simply needs to provide two new subclasses of these two base classes.

    10 

    11   To make that subclassing process easy, two skeleton classes are provided in

    12   the src/node directory: simple-net-device.h (ns3::SimpleNetDevice) and 

    13   simple-channel.h (ns3::SimpleChannel) implement a broadcast passthru medium 

    14   using 48bit MAC addresses without any kind of MAC access algorithm or PHY 

    15   layer modeling.

    16 

    17   The ns3::SimpleChannel class is really very simple: it provides

    18   an implementation for the ns3::Channel::GetNDevices and ns3::Channel::GetDevice

    19   methods defined in the Channel base class and, then defines the channel-specific

    20   send and add methods:

    21 - The Add method is used by SimpleNetDevice::SetChannel to register a new 

    22   SimpleNetDevice with its associated channel.

    23 - The Send method is used by SimpleNetDevice::Send to send a packet over the

    24   broadcast medium and ensure that it gets delivered to all associated devices

    25   (except the sender).

    26 

    27 \code

    28 class SimpleChannel : public Channel

    29 {

    30 public:

    31   static TypeId GetTypeId (void);

    32   SimpleChannel ();

    33 

    34   void Send (Ptr<Packet> p, uint16_t protocol, Mac48Address to, Mac48Address from,

    35 	     Ptr<SimpleNetDevice> sender);

    36 

    37   void Add (Ptr<SimpleNetDevice> device);

    38 

    39   // inherited from ns3::Channel

    40   virtual uint32_t GetNDevices (void) const;

    41   virtual Ptr<NetDevice> GetDevice (uint32_t i) const;

    42 

    43 private:

    44   std::vector<Ptr<SimpleNetDevice> > m_devices;

    45 };

    46 \endcode

    47 

    48 The SimpleNetDevice class is also trivial since it implements no special

    49 MAC-layer processing:

    50 \code

    51 class SimpleNetDevice : public NetDevice

    52 {

    53 public:

    54   static TypeId GetTypeId (void);

    55   SimpleNetDevice ();

    56 

    57   void Receive (Ptr<Packet> packet, uint16_t protocol, Mac48Address to, Mac48Address from);

    58   void SetChannel (Ptr<SimpleChannel> channel);

    59   void SetAddress (Mac48Address address);

    60 

    61   // inherited from NetDevice base class.

    62   virtual void SetName(const std::string name);

    63   ...

    64 };

    65 \endcode

    66 

    67 The code below illustrates how the three model-specific methods defined above are

    68 implemented:

    69 

    70 \code

    71 void 

    72 SimpleNetDevice::Receive (Ptr<Packet> packet, uint16_t protocol, 

    73 			  Mac48Address to, Mac48Address from)

    74 {

    75   if (to == m_address || to == Mac48Address::GetBroadcast ())

    76     {

    77       m_rxCallback (this, packet, protocol, from);

    78     }

    79 }

    80 void 

    81 SimpleNetDevice::SetChannel (Ptr<SimpleChannel> channel)

    82 {

    83   m_channel = channel;

    84   m_channel->Add (this);

    85 }

    86 void 

    87 SimpleNetDevice::SetAddress (Mac48Address address)

    88 {

    89   m_address = address;

    90 }

    91 \endcode

    92 

    93 */