Merge branch 'master' of git@ettus.sourcerepo.com:ettus/uhd into u1e_uhd

Conflicts:
	host/apps/CMakeLists.txt
	host/lib/usrp/usrp2/usrp2_impl.cpp

7 files changed, 412 insertions, 259 deletions

diff --git a/host/lib/usrp/usrp2/dboard_impl.cpp b/host/lib/usrp/usrp2/dboard_impl.cpp
index 32c64f541..6d957436e 100644
--- a/host/lib/usrp/usrp2/dboard_impl.cpp
+++ b/host/lib/usrp/usrp2/dboard_impl.cpp
@@ -16,6 +16,7 @@
 //
 
 #include <uhd/utils.hpp>
+#include <boost/format.hpp>
 #include "usrp2_impl.hpp"
 #include "dboard_interface.hpp"
 
@@ -70,7 +71,7 @@ void usrp2_impl::rx_dboard_get(const wax::obj &key_, wax::obj &val){
     boost::tie(key, name) = extract_named_prop(key_);
 
     //handle the get request conditioned on the key
-    switch(wax::cast<dboard_prop_t>(key)){
+    switch(key.as<dboard_prop_t>()){
     case DBOARD_PROP_NAME:
         val = std::string("usrp2 dboard (rx unit)");
         return;
@@ -83,8 +84,8 @@ void usrp2_impl::rx_dboard_get(const wax::obj &key_, wax::obj &val){
         val = _dboard_manager->get_rx_subdev_names();
         return;
 
-    case DBOARD_PROP_CODEC:
-        throw std::runtime_error("unhandled prop in usrp2 dboard");
+    //case DBOARD_PROP_CODEC:
+    //    throw std::runtime_error("unhandled prop in usrp2 dboard");
     }
 }
 
@@ -100,7 +101,7 @@ void usrp2_impl::tx_dboard_get(const wax::obj &key_, wax::obj &val){
     boost::tie(key, name) = extract_named_prop(key_);
 
     //handle the get request conditioned on the key
-    switch(wax::cast<dboard_prop_t>(key)){
+    switch(key.as<dboard_prop_t>()){
     case DBOARD_PROP_NAME:
         val = std::string("usrp2 dboard (tx unit)");
         return;
@@ -113,8 +114,8 @@ void usrp2_impl::tx_dboard_get(const wax::obj &key_, wax::obj &val){
         val = _dboard_manager->get_tx_subdev_names();
         return;
 
-    case DBOARD_PROP_CODEC:
-        throw std::runtime_error("unhandled prop in usrp2 dboard");
+    //case DBOARD_PROP_CODEC:
+    //    throw std::runtime_error("unhandled prop in usrp2 dboard");
     }
 }
 
diff --git a/host/lib/usrp/usrp2/dsp_impl.cpp b/host/lib/usrp/usrp2/dsp_impl.cpp
index 22c00d99a..7520c1757 100644
--- a/host/lib/usrp/usrp2/dsp_impl.cpp
+++ b/host/lib/usrp/usrp2/dsp_impl.cpp
@@ -16,11 +16,15 @@
 //
 
 #include <uhd/utils.hpp>
+#include <boost/format.hpp>
 #include <boost/assign/list_of.hpp>
 #include "usrp2_impl.hpp"
 
 using namespace uhd;
 
+static const size_t default_decim = 16;
+static const size_t default_interp = 16;
+
 /***********************************************************************
  * DDC Helper Methods
  **********************************************************************/
@@ -36,6 +40,10 @@ static uint32_t calculate_freq_word_and_update_actual_freq(freq_t &freq, freq_t
     return freq_word;
 }
 
+static uint32_t calculate_iq_scale_word(int16_t i, int16_t q){
+    return (uint16_t(i) << 16) | (uint16_t(q) << 0);
+}
+
 void usrp2_impl::init_ddc_config(void){
     //create the ddc in the rx dsp dict
     _rx_dsps["ddc0"] = wax_obj_proxy(
@@ -44,7 +52,7 @@ void usrp2_impl::init_ddc_config(void){
     );
 
     //initial config and update
-    _ddc_decim = 16;
+    _ddc_decim = default_decim;
     _ddc_freq = 0;
     update_ddc_config();
 
@@ -61,6 +69,10 @@ void usrp2_impl::update_ddc_config(void){
         calculate_freq_word_and_update_actual_freq(_ddc_freq, get_master_clock_freq())
     );
     out_data.data.ddc_args.decim = htonl(_ddc_decim);
+    static const uint32_t default_rx_scale_iq = 1024;
+    out_data.data.ddc_args.scale_iq = htonl(
+        calculate_iq_scale_word(default_rx_scale_iq, default_rx_scale_iq)
+    );
 
     //send and recv
     usrp2_ctrl_data_t in_data = ctrl_send_and_recv(out_data);
@@ -74,6 +86,7 @@ void usrp2_impl::update_ddc_enabled(void){
     out_data.data.streaming.enabled = (_ddc_enabled)? 1 : 0;
     out_data.data.streaming.secs =  htonl(_ddc_stream_at.secs);
     out_data.data.streaming.ticks = htonl(_ddc_stream_at.ticks);
+    out_data.data.streaming.samples = htonl(_max_rx_samples_per_packet);
 
     //send and recv
     usrp2_ctrl_data_t in_data = ctrl_send_and_recv(out_data);
@@ -89,7 +102,7 @@ void usrp2_impl::update_ddc_enabled(void){
 void usrp2_impl::ddc_get(const wax::obj &key, wax::obj &val){
     //handle the case where the key is an expected dsp property
     if (key.type() == typeid(dsp_prop_t)){
-        switch(wax::cast<dsp_prop_t>(key)){
+        switch(key.as<dsp_prop_t>()){
         case DSP_PROP_NAME:
             val = std::string("usrp2 ddc0");
             return;
@@ -98,7 +111,7 @@ void usrp2_impl::ddc_get(const wax::obj &key, wax::obj &val){
                 prop_names_t others = boost::assign::list_of
                     ("rate")
                     ("decim")
-                    ("decim_rates")
+                    ("decims")
                     ("freq")
                     ("enabled")
                     ("stream_at")
@@ -110,7 +123,7 @@ void usrp2_impl::ddc_get(const wax::obj &key, wax::obj &val){
     }
 
     //handle string-based properties specific to this dsp
-    std::string key_name = wax::cast<std::string>(key);
+    std::string key_name = key.as<std::string>();
     if (key_name == "rate"){
         val = get_master_clock_freq();
         return;
@@ -119,7 +132,7 @@ void usrp2_impl::ddc_get(const wax::obj &key, wax::obj &val){
         val = _ddc_decim;
         return;
     }
-    else if (key_name == "decim_rates"){
+    else if (key_name == "decims"){
         val = _allowed_decim_and_interp_rates;
         return;
     }
@@ -139,20 +152,19 @@ void usrp2_impl::ddc_get(const wax::obj &key, wax::obj &val){
 
 void usrp2_impl::ddc_set(const wax::obj &key, const wax::obj &val){
     //handle string-based properties specific to this dsp
-    std::string key_name = wax::cast<std::string>(key);
+    std::string key_name = key.as<std::string>();
     if (key_name == "decim"){
-        size_t new_decim = wax::cast<size_t>(val);
-        ASSERT_THROW(std::has(
-            _allowed_decim_and_interp_rates.begin(),
-            _allowed_decim_and_interp_rates.end(),
-            new_decim
-        ));
+        size_t new_decim = val.as<size_t>();
+        assert_has(
+            _allowed_decim_and_interp_rates,
+            new_decim, "usrp2 decimation"
+        );
         _ddc_decim = new_decim; //shadow
         update_ddc_config();
         return;
     }
     else if (key_name == "freq"){
-        freq_t new_freq = wax::cast<freq_t>(val);
+        freq_t new_freq = val.as<freq_t>();
         ASSERT_THROW(new_freq <= get_master_clock_freq()/2.0);
         ASSERT_THROW(new_freq >= -get_master_clock_freq()/2.0);
         _ddc_freq = new_freq; //shadow
@@ -160,13 +172,13 @@ void usrp2_impl::ddc_set(const wax::obj &key, const wax::obj &val){
         return;
     }
     else if (key_name == "enabled"){
-        bool new_enabled = wax::cast<bool>(val);
+        bool new_enabled = val.as<bool>();
         _ddc_enabled = new_enabled; //shadow
         update_ddc_enabled();
         return;
     }
     else if (key_name == "stream_at"){
-        time_spec_t new_stream_at = wax::cast<time_spec_t>(val);
+        time_spec_t new_stream_at = val.as<time_spec_t>();
         _ddc_stream_at = new_stream_at; //shadow
         //update_ddc_enabled(); //dont update from here
         return;
@@ -188,7 +200,7 @@ void usrp2_impl::init_duc_config(void){
     );
 
     //initial config and update
-    _duc_interp = 16;
+    _duc_interp = default_interp;
     _duc_freq = 0;
     update_duc_config();
 }
@@ -209,7 +221,9 @@ void usrp2_impl::update_duc_config(void){
         calculate_freq_word_and_update_actual_freq(_duc_freq, get_master_clock_freq())
     );
     out_data.data.duc_args.interp = htonl(_duc_interp);
-    out_data.data.duc_args.scale_iq = htonl(scale);
+    out_data.data.duc_args.scale_iq = htonl(
+        calculate_iq_scale_word(scale, scale)
+    );
 
     //send and recv
     usrp2_ctrl_data_t in_data = ctrl_send_and_recv(out_data);
@@ -222,7 +236,7 @@ void usrp2_impl::update_duc_config(void){
 void usrp2_impl::duc_get(const wax::obj &key, wax::obj &val){
     //handle the case where the key is an expected dsp property
     if (key.type() == typeid(dsp_prop_t)){
-        switch(wax::cast<dsp_prop_t>(key)){
+        switch(key.as<dsp_prop_t>()){
         case DSP_PROP_NAME:
             val = std::string("usrp2 duc0");
             return;
@@ -231,7 +245,7 @@ void usrp2_impl::duc_get(const wax::obj &key, wax::obj &val){
                 prop_names_t others = boost::assign::list_of
                     ("rate")
                     ("interp")
-                    ("interp_rates")
+                    ("interps")
                     ("freq")
                 ;
                 val = others;
@@ -241,7 +255,7 @@ void usrp2_impl::duc_get(const wax::obj &key, wax::obj &val){
     }
 
     //handle string-based properties specific to this dsp
-    std::string key_name = wax::cast<std::string>(key);
+    std::string key_name = key.as<std::string>();
     if (key_name == "rate"){
         val = get_master_clock_freq();
         return;
@@ -250,7 +264,7 @@ void usrp2_impl::duc_get(const wax::obj &key, wax::obj &val){
         val = _duc_interp;
         return;
     }
-    else if (key_name == "interp_rates"){
+    else if (key_name == "interps"){
         val = _allowed_decim_and_interp_rates;
         return;
     }
@@ -266,20 +280,19 @@ void usrp2_impl::duc_get(const wax::obj &key, wax::obj &val){
 
 void usrp2_impl::duc_set(const wax::obj &key, const wax::obj &val){
     //handle string-based properties specific to this dsp
-    std::string key_name = wax::cast<std::string>(key);
+    std::string key_name = key.as<std::string>();
     if (key_name == "interp"){
-        size_t new_interp = wax::cast<size_t>(val);
-        ASSERT_THROW(std::has(
-            _allowed_decim_and_interp_rates.begin(),
-            _allowed_decim_and_interp_rates.end(),
-            new_interp
-        ));
+        size_t new_interp = val.as<size_t>();
+        assert_has(
+            _allowed_decim_and_interp_rates,
+            new_interp, "usrp2 interpolation"
+        );
         _duc_interp = new_interp; //shadow
         update_duc_config();
         return;
     }
     else if (key_name == "freq"){
-        freq_t new_freq = wax::cast<freq_t>(val);
+        freq_t new_freq = val.as<freq_t>();
         ASSERT_THROW(new_freq <= get_master_clock_freq()/2.0);
         ASSERT_THROW(new_freq >= -get_master_clock_freq()/2.0);
         _duc_freq = new_freq; //shadow
diff --git a/host/lib/usrp/usrp2/fw_common.h b/host/lib/usrp/usrp2/fw_common.h
index 3def8ddaa..10c1ef8cf 100644
--- a/host/lib/usrp/usrp2/fw_common.h
+++ b/host/lib/usrp/usrp2/fw_common.h
@@ -27,6 +27,10 @@
 extern "C" {
 #endif
 
+// size of the vrt header and trailer to the host
+#define USRP2_HOST_RX_VRT_HEADER_WORDS32 5
+#define USRP2_HOST_RX_VRT_TRAILER_WORDS32 1 //FIXME fpga sets wrong header size when no trailer present
+
 // udp ports for the usrp2 communication
 // Dynamic and/or private ports: 49152-65535
 #define USRP2_UDP_CTRL_PORT 49152
@@ -87,6 +91,9 @@ typedef enum{
     USRP2_CTRL_ID_SETUP_THIS_DUC_FOR_ME_BRO,
     USRP2_CTRL_ID_TOTALLY_SETUP_THE_DUC_DUDE,
 
+    USRP2_CTRL_ID_GOT_A_NEW_TIME_FOR_YOU_BRO,
+    USRP2_CTRL_ID_SWEET_I_GOT_THAT_TIME_DUDE,
+
     USRP2_CTRL_ID_PEACE_OUT
 
 } usrp2_ctrl_id_t;
@@ -168,18 +175,25 @@ typedef struct{
         struct {
             uint32_t freq_word;
             uint32_t decim;
+            uint32_t scale_iq;
         } ddc_args;
         struct {
             uint8_t enabled;
             uint8_t _pad[3];
             uint32_t secs;
             uint32_t ticks;
+            uint32_t samples;
         } streaming;
         struct {
             uint32_t freq_word;
             uint32_t interp;
             uint32_t scale_iq;
         } duc_args;
+        struct {
+            uint32_t secs;
+            uint32_t ticks;
+            uint8_t now;
+        } time_args;
     } data;
 } usrp2_ctrl_data_t;
 
diff --git a/host/lib/usrp/usrp2/io_impl.cpp b/host/lib/usrp/usrp2/io_impl.cpp
index 43334ddc6..cc7746720 100644
--- a/host/lib/usrp/usrp2/io_impl.cpp
+++ b/host/lib/usrp/usrp2/io_impl.cpp
@@ -16,12 +16,13 @@
 //
 
 #include <complex>
-#include <boost/shared_array.hpp>
 #include <boost/format.hpp>
 #include "usrp2_impl.hpp"
 
 using namespace uhd;
 using namespace uhd::usrp;
+using namespace uhd::transport;
+namespace asio = boost::asio;
 
 /***********************************************************************
  * Constants
@@ -29,214 +30,228 @@ using namespace uhd::usrp;
 typedef std::complex<float>   fc32_t;
 typedef std::complex<int16_t> sc16_t;
 
-static const float float_scale_factor = pow(2.0, 15);
-
-//max length with header, stream id, seconds, fractional seconds
-static const size_t max_vrt_header_words = 5;
+static const float shorts_per_float = pow(2.0, 15);
+static const float floats_per_short = 1.0/shorts_per_float;
 
 /***********************************************************************
  * Helper Functions
  **********************************************************************/
-static inline void host_floats_to_usrp2_shorts(
-    int16_t *usrp2_shorts,
-    const float *host_floats,
-    size_t num_samps
-){
-    for(size_t i = 0; i < num_samps; i++){
-        usrp2_shorts[i] = htons(int16_t(host_floats[i]*float_scale_factor));
-    }
+void usrp2_impl::io_init(void){
+    //initially empty copy buffer
+    _rx_copy_buff = asio::buffer("", 0);
+
+    //send a small data packet so the usrp2 knows the udp source port
+    uint32_t zero_data = 0;
+    _data_transport->send(asio::buffer(&zero_data, sizeof(zero_data)));
+}
+
+#define unrolled_loop(__i, __len, __inst) {\
+    size_t __i = 0; \
+    while(__i < (__len & ~0x7)){ \
+        __inst; __i++; __inst; __i++; \
+        __inst; __i++; __inst; __i++; \
+        __inst; __i++; __inst; __i++; \
+        __inst; __i++; __inst; __i++; \
+    } \
+    while(__i < __len){ \
+        __inst; __i++;\
+    } \
 }
 
-static inline void usrp2_shorts_to_host_floats(
-    float *host_floats,
-    const int16_t *usrp2_shorts,
+// set a boolean flag that indicates the endianess
+#ifdef HAVE_BIG_ENDIAN
+static const bool is_big_endian = true;
+#else
+static const bool is_big_endian = false;
+#endif
+
+static inline void host_floats_to_usrp2_items(
+    uint32_t *usrp2_items,
+    const fc32_t *host_floats,
     size_t num_samps
 ){
-    for(size_t i = 0; i < num_samps; i++){
-        host_floats[i] = float(ntohs(usrp2_shorts[i])/float_scale_factor);
-    }
+    unrolled_loop(i, num_samps,{
+        uint16_t real = host_floats[i].real()*shorts_per_float;
+        uint16_t imag = host_floats[i].imag()*shorts_per_float;
+        usrp2_items[i] = htonl((real << 16) | (imag << 0));
+    });
 }
 
-static inline void host_shorts_to_usrp2_shorts(
-    int16_t *usrp2_shorts,
-    const int16_t *host_shorts,
+static inline void usrp2_items_to_host_floats(
+    fc32_t *host_floats,
+    const uint32_t *usrp2_items,
     size_t num_samps
 ){
-    for(size_t i = 0; i < num_samps; i++){
-        usrp2_shorts[i] = htons(host_shorts[i]);
-    }
+    unrolled_loop(i, num_samps,{
+        uint32_t item = ntohl(usrp2_items[i]);
+        int16_t real = item >> 16;
+        int16_t imag = item >> 0;
+        host_floats[i] = fc32_t(real*floats_per_short, imag*floats_per_short);
+    });
 }
 
-static inline void usrp2_shorts_to_host_shorts(
-    int16_t *host_shorts,
-    const int16_t *usrp2_shorts,
+static inline void host_items_to_usrp2_items(
+    uint32_t *usrp2_items,
+    const uint32_t *host_items,
     size_t num_samps
 ){
-    for(size_t i = 0; i < num_samps; i++){
-        host_shorts[i] = ntohs(usrp2_shorts[i]);
+    if (is_big_endian){
+        std::memcpy(usrp2_items, host_items, num_samps*sizeof(uint32_t));
+    }
+    else{
+        unrolled_loop(i, num_samps, usrp2_items[i] = htonl(host_items[i]));
     }
 }
 
-/***********************************************************************
- * Send Raw Data
- **********************************************************************/
-size_t usrp2_impl::send_raw(
-    const boost::asio::const_buffer &buff,
-    const uhd::metadata_t &metadata
+static inline void usrp2_items_to_host_items(
+    uint32_t *host_items,
+    const uint32_t *usrp2_items,
+    size_t num_samps
 ){
-    std::vector<boost::asio::const_buffer> buffs(2);
-    uint32_t vrt_hdr[max_vrt_header_words];
-    uint32_t vrt_hdr_flags = 0;
-    size_t num_vrt_hdr_words = 1;
-
-    //load the vrt header and flags
-    if(metadata.has_stream_id){
-        vrt_hdr_flags |= (0x1 << 28); //IF Data packet with Stream Identifier
-        vrt_hdr[num_vrt_hdr_words++] = htonl(metadata.stream_id);
+    if (is_big_endian){
+        std::memcpy(host_items, usrp2_items, num_samps*sizeof(uint32_t));
     }
-    if(metadata.has_time_spec){
-        vrt_hdr_flags |= (0x3 << 22) | (0x1 << 20); //TSI: Other, TSF: Sample Count Timestamp
-        vrt_hdr[num_vrt_hdr_words++] = htonl(metadata.time_spec.secs);
-        vrt_hdr[num_vrt_hdr_words++] = htonl(metadata.time_spec.ticks);
-        vrt_hdr[num_vrt_hdr_words++] = 0; //unused part of fractional seconds
+    else{
+        unrolled_loop(i, num_samps, host_items[i] = ntohl(usrp2_items[i]));
     }
-    vrt_hdr_flags |= (metadata.start_of_burst)? (0x1 << 25) : 0;
-    vrt_hdr_flags |= (metadata.end_of_burst)?   (0x1 << 24) : 0;
-
-    //fill in complete header word
-    vrt_hdr[0] = htonl(vrt_hdr_flags |
-        ((_stream_id_to_packet_seq[metadata.stream_id]++ & 0xf) << 16) |
-        ((boost::asio::buffer_size(buff)/sizeof(uint32_t)) & 0xffff)
-    );
-
-    //load the buffer vector
-    size_t vrt_hdr_size = num_vrt_hdr_words*sizeof(uint32_t);
-    buffs[0] = boost::asio::buffer(&vrt_hdr, vrt_hdr_size);
-    buffs[1] = buff;
-
-    //send and return number of samples
-    return (_data_transport->send(buffs) - vrt_hdr_size)/sizeof(sc16_t);
 }
 
 /***********************************************************************
  * Receive Raw Data
  **********************************************************************/
-size_t usrp2_impl::recv_raw(
-    const boost::asio::mutable_buffer &buff,
-    uhd::metadata_t &metadata
-){
-    //load the buffer vector
-    std::vector<boost::asio::mutable_buffer> buffs(2);
-    uint32_t vrt_hdr[max_vrt_header_words];
-    buffs[0] = boost::asio::buffer(vrt_hdr, max_vrt_header_words);
-    buffs[1] = buff;
+void usrp2_impl::recv_raw(rx_metadata_t &metadata){
+    //do a receive
+    _rx_smart_buff = _data_transport->recv();
 
-    //receive into the buffers
-    size_t bytes_recvd = _data_transport->recv(buffs);
+    //unpack the vrt header
+    size_t num_packet_words32 = asio::buffer_size(_rx_smart_buff->get())/sizeof(uint32_t);
+    if (num_packet_words32 == 0){
+        _rx_copy_buff = boost::asio::buffer("", 0);
+        return; //must exit here after setting the buffer
+    }
+    const uint32_t *vrt_hdr = asio::buffer_cast<const uint32_t *>(_rx_smart_buff->get());
+    size_t num_header_words32_out, num_payload_words32_out, packet_count_out;
+    try{
+        vrt::unpack(
+            metadata,                //output
+            vrt_hdr,                 //input
+            num_header_words32_out,  //output
+            num_payload_words32_out, //output
+            num_packet_words32,      //input
+            packet_count_out         //output
+        );
+    }catch(const std::exception &e){
+        std::cerr << "bad vrt header: " << e.what() << std::endl;
+        _rx_copy_buff = boost::asio::buffer("", 0);
+        return; //must exit here after setting the buffer
+    }
 
-    //failure case
-    if (bytes_recvd < max_vrt_header_words*sizeof(uint32_t)) return 0;
+    //handle the packet count / sequence number
+    size_t expected_packet_count = _rx_stream_id_to_packet_seq[metadata.stream_id];
+    if (packet_count_out != expected_packet_count){
+        std::cerr << "bad packet count: " << packet_count_out << std::endl;
+    }
+    _rx_stream_id_to_packet_seq[metadata.stream_id] = (packet_count_out+1)%16;
 
-    //unpack the vrt header
-    metadata = uhd::metadata_t();
-    uint32_t vrt_header = ntohl(vrt_hdr[0]);
-    metadata.has_stream_id = true;
-    metadata.stream_id = ntohl(vrt_hdr[1]);
-    metadata.has_time_spec = true;
-    metadata.time_spec.secs = ntohl(vrt_hdr[2]);
-    metadata.time_spec.ticks = ntohl(vrt_hdr[3]);
-
-    //return the number of samples received
-    size_t num_words = vrt_header & 0xffff;
-    return (num_words*sizeof(uint32_t))/sizeof(sc16_t);
+    //setup the rx buffer to point to the data
+    _rx_copy_buff = asio::buffer(
+        vrt_hdr + num_header_words32_out,
+        num_payload_words32_out*sizeof(uint32_t)
+    );
 }
 
 /***********************************************************************
  * Send Data
  **********************************************************************/
 size_t usrp2_impl::send(
-    const boost::asio::const_buffer &buff,
-    const uhd::metadata_t &metadata,
+    const asio::const_buffer &buff,
+    const tx_metadata_t &metadata,
     const std::string &type
 ){
-    if (type == "fc32"){
-        size_t num_samps = boost::asio::buffer_size(buff)/sizeof(fc32_t);
-        boost::shared_array<sc16_t> raw_mem(new sc16_t[num_samps]);
-        boost::asio::mutable_buffer raw_buff(raw_mem.get(), num_samps*sizeof(sc16_t));
-
-        host_floats_to_usrp2_shorts(
-            boost::asio::buffer_cast<int16_t*>(raw_buff),
-            boost::asio::buffer_cast<const float*>(buff),
-            num_samps*2 //double for complex
-        );
-
-        return send_raw(raw_buff, metadata);
+    uint32_t tx_mem[_mtu/sizeof(uint32_t)];
+    uint32_t *items = tx_mem + vrt::max_header_words32; //offset for data
+    size_t num_samps = _max_tx_samples_per_packet;
+
+    //calculate the number of samples to be copied
+    //and copy the samples into the send buffer
+    if (type == "32fc"){
+        num_samps = std::min(asio::buffer_size(buff)/sizeof(fc32_t), num_samps);
+        host_floats_to_usrp2_items(items, asio::buffer_cast<const fc32_t*>(buff), num_samps);
+    }
+    else if (type == "16sc"){
+        num_samps = std::min(asio::buffer_size(buff)/sizeof(sc16_t), num_samps);
+        host_items_to_usrp2_items(items, asio::buffer_cast<const uint32_t*>(buff), num_samps);
+    }
+    else{
+        throw std::runtime_error(str(boost::format("usrp2 send: cannot handle type \"%s\"") % type));
     }
 
-    if (type == "sc16"){
-        #ifdef HAVE_BIG_ENDIAN
-        return send_raw(buff, metadata);
-        #else
-        size_t num_samps = boost::asio::buffer_size(buff)/sizeof(sc16_t);
-        boost::shared_array<sc16_t> raw_mem(new sc16_t[num_samps]);
-        boost::asio::mutable_buffer raw_buff(raw_mem.get(), num_samps*sizeof(sc16_t));
-
-        host_shorts_to_usrp2_shorts(
-            boost::asio::buffer_cast<int16_t*>(raw_buff),
-            boost::asio::buffer_cast<const int16_t*>(buff),
-            num_samps*2 //double for complex
-        );
+    uint32_t vrt_hdr[vrt::max_header_words32];
+    size_t num_header_words32, num_packet_words32;
+    size_t packet_count = _tx_stream_id_to_packet_seq[metadata.stream_id]++;
+
+    //pack metadata into a vrt header
+    vrt::pack(
+        metadata,            //input
+        vrt_hdr,             //output
+        num_header_words32,  //output
+        num_samps,           //input
+        num_packet_words32,  //output
+        packet_count         //input
+    );
 
-        return send_raw(raw_buff, metadata);
-        #endif
-    }
+    //copy in the vrt header (yes we left space)
+    items -= num_header_words32;
+    std::memcpy(items, vrt_hdr, num_header_words32*sizeof(uint32_t));
 
-    throw std::runtime_error(str(boost::format("usrp2 send: cannot handle type \"%s\"") % type));
+    //send and return number of samples
+    _data_transport->send(asio::buffer(items, num_packet_words32*sizeof(uint32_t)));
+    return num_samps;
 }
 
 /***********************************************************************
  * Receive Data
  **********************************************************************/
 size_t usrp2_impl::recv(
-    const boost::asio::mutable_buffer &buff,
-    uhd::metadata_t &metadata,
+    const asio::mutable_buffer &buff,
+    rx_metadata_t &metadata,
     const std::string &type
 ){
-    if (type == "fc32"){
-        size_t num_samps = boost::asio::buffer_size(buff)/sizeof(fc32_t);
-        boost::shared_array<sc16_t> raw_mem(new sc16_t[num_samps]);
-        boost::asio::mutable_buffer raw_buff(raw_mem.get(), num_samps*sizeof(sc16_t));
-
-        num_samps = recv_raw(raw_buff, metadata);
-
-        usrp2_shorts_to_host_floats(
-            boost::asio::buffer_cast<float*>(buff),
-            boost::asio::buffer_cast<const int16_t*>(raw_buff),
-            num_samps*2 //double for complex
-        );
-
-        return num_samps;
+    //perform a receive if no rx data is waiting to be copied
+    if (asio::buffer_size(_rx_copy_buff) == 0){
+        recv_raw(metadata);
+    }
+    //otherwise flag the metadata to show that is is a fragment
+    else{
+        metadata = rx_metadata_t();
+        metadata.is_fragment = true;
     }
 
-    if (type == "sc16"){
-        #ifdef HAVE_BIG_ENDIAN
-        return recv_raw(buff, metadata);
-        #else
-        size_t num_samps = boost::asio::buffer_size(buff)/sizeof(sc16_t);
-        boost::shared_array<sc16_t> raw_mem(new sc16_t[num_samps]);
-        boost::asio::mutable_buffer raw_buff(raw_mem.get(), num_samps*sizeof(sc16_t));
-
-        num_samps = recv_raw(raw_buff, metadata);
-
-        usrp2_shorts_to_host_shorts(
-            boost::asio::buffer_cast<int16_t*>(buff),
-            boost::asio::buffer_cast<const int16_t*>(raw_buff),
-            num_samps*2 //double for complex
-        );
-
-        return num_samps;
-        #endif
+    //extract the number of samples available to copy
+    //and a pointer into the usrp2 received items memory
+    size_t bytes_to_copy = asio::buffer_size(_rx_copy_buff);
+    if (bytes_to_copy == 0) return 0; //nothing to receive
+    size_t num_samps = bytes_to_copy/sizeof(uint32_t);
+    const uint32_t *items = asio::buffer_cast<const uint32_t*>(_rx_copy_buff);
+
+    //calculate the number of samples to be copied
+    //and copy the samples from the recv buffer
+    if (type == "32fc"){
+        num_samps = std::min(asio::buffer_size(buff)/sizeof(fc32_t), num_samps);
+        usrp2_items_to_host_floats(asio::buffer_cast<fc32_t*>(buff), items, num_samps);
+    }
+    else if (type == "16sc"){
+        num_samps = std::min(asio::buffer_size(buff)/sizeof(sc16_t), num_samps);
+        usrp2_items_to_host_items(asio::buffer_cast<uint32_t*>(buff), items, num_samps);
     }
+    else{
+        throw std::runtime_error(str(boost::format("usrp2 recv: cannot handle type \"%s\"") % type));
+    }
+
+    //update the rx copy buffer to reflect the bytes copied
+    _rx_copy_buff = asio::buffer(
+        items + num_samps, bytes_to_copy - num_samps*sizeof(uint32_t)
+    );
 
-    throw std::runtime_error(str(boost::format("usrp2 recv: cannot handle type \"%s\"") % type));
+    return num_samps;
 }
diff --git a/host/lib/usrp/usrp2/mboard_impl.cpp b/host/lib/usrp/usrp2/mboard_impl.cpp
index cc73b229c..4b15c7f3e 100644
--- a/host/lib/usrp/usrp2/mboard_impl.cpp
+++ b/host/lib/usrp/usrp2/mboard_impl.cpp
@@ -16,6 +16,7 @@
 //
 
 #include <uhd/utils.hpp>
+#include <boost/assign/list_of.hpp>
 #include "usrp2_impl.hpp"
 
 using namespace uhd;
@@ -28,6 +29,10 @@ void usrp2_impl::mboard_init(void){
         boost::bind(&usrp2_impl::mboard_get, this, _1, _2),
         boost::bind(&usrp2_impl::mboard_set, this, _1, _2)
     );
+
+    //set the time on the usrp2 as close as possible to the system utc time
+    boost::posix_time::ptime now(boost::posix_time::microsec_clock::universal_time());
+    set_time_spec(time_spec_t(now, get_master_clock_freq()), true);
 }
 
 void usrp2_impl::init_clock_config(void){
@@ -64,6 +69,19 @@ void usrp2_impl::update_clock_config(void){
     ASSERT_THROW(htonl(in_data.id) == USRP2_CTRL_ID_GOT_THE_NEW_CLOCK_CONFIG_DUDE);
 }
 
+void usrp2_impl::set_time_spec(const time_spec_t &time_spec, bool now){
+    //setup the out data
+    usrp2_ctrl_data_t out_data;
+    out_data.id = htonl(USRP2_CTRL_ID_GOT_A_NEW_TIME_FOR_YOU_BRO);
+    out_data.data.time_args.secs  = htonl(time_spec.secs);
+    out_data.data.time_args.ticks = htonl(time_spec.ticks);
+    out_data.data.time_args.now   = (now)? 1 : 0;
+
+    //send and recv
+    usrp2_ctrl_data_t in_data = ctrl_send_and_recv(out_data);
+    ASSERT_THROW(htonl(in_data.id) == USRP2_CTRL_ID_SWEET_I_GOT_THAT_TIME_DUDE);
+}
+
 /***********************************************************************
  * MBoard Get Properties
  **********************************************************************/
@@ -71,17 +89,54 @@ void usrp2_impl::mboard_get(const wax::obj &key_, wax::obj &val){
     wax::obj key; std::string name;
     boost::tie(key, name) = extract_named_prop(key_);
 
+    //handle the other props
+    if (key.type() == typeid(std::string)){
+        if (key.as<std::string>() == "mac-addr"){
+            //setup the out data
+            usrp2_ctrl_data_t out_data;
+            out_data.id = htonl(USRP2_CTRL_ID_GIVE_ME_YOUR_MAC_ADDR_BRO);
+
+            //send and recv
+            usrp2_ctrl_data_t in_data = ctrl_send_and_recv(out_data);
+            ASSERT_THROW(htonl(in_data.id) == USRP2_CTRL_ID_THIS_IS_MY_MAC_ADDR_DUDE);
+
+            //extract the address
+            val = reinterpret_cast<mac_addr_t*>(in_data.data.mac_addr)->to_string();
+            return;
+        }
+
+        if (key.as<std::string>() == "ip-addr"){
+            //setup the out data
+            usrp2_ctrl_data_t out_data;
+            out_data.id = htonl(USRP2_CTRL_ID_GIVE_ME_YOUR_IP_ADDR_BRO);
+
+            //send and recv
+            usrp2_ctrl_data_t in_data = ctrl_send_and_recv(out_data);
+            ASSERT_THROW(htonl(in_data.id) == USRP2_CTRL_ID_THIS_IS_MY_IP_ADDR_DUDE);
+
+            //extract the address
+            val = boost::asio::ip::address_v4(ntohl(in_data.data.ip_addr)).to_string();
+            return;
+        }
+    }
+
     //handle the get request conditioned on the key
-    switch(wax::cast<mboard_prop_t>(key)){
+    switch(key.as<mboard_prop_t>()){
     case MBOARD_PROP_NAME:
         val = std::string("usrp2 mboard");
         return;
 
-    case MBOARD_PROP_OTHERS:
-        val = prop_names_t(); //empty other props
+    case MBOARD_PROP_OTHERS:{
+            prop_names_t others = boost::assign::list_of
+                ("mac-addr")
+                ("ip-addr")
+            ;
+            val = others;
+        }
         return;
 
     case MBOARD_PROP_RX_DBOARD:
+        ASSERT_THROW(_rx_dboards.has_key(name));
         val = _rx_dboards[name].get_link();
         return;
 
@@ -90,6 +145,7 @@ void usrp2_impl::mboard_get(const wax::obj &key_, wax::obj &val){
         return;
 
     case MBOARD_PROP_TX_DBOARD:
+        ASSERT_THROW(_tx_dboards.has_key(name));
         val = _tx_dboards[name].get_link();
         return;
 
@@ -97,17 +153,12 @@ void usrp2_impl::mboard_get(const wax::obj &key_, wax::obj &val){
         val = prop_names_t(_tx_dboards.get_keys());
         return;
 
-    case MBOARD_PROP_MTU:
-        // FIXME we dont know the real MTU...
-        // give them something to fragment about
-        val = size_t(1500);
-        return;
-
     case MBOARD_PROP_CLOCK_RATE:
         val = freq_t(get_master_clock_freq());
         return;
 
     case MBOARD_PROP_RX_DSP:
+        ASSERT_THROW(_rx_dsps.has_key(name));
         val = _rx_dsps[name].get_link();
         return;
 
@@ -116,6 +167,7 @@ void usrp2_impl::mboard_get(const wax::obj &key_, wax::obj &val){
         return;
 
     case MBOARD_PROP_TX_DSP:
+        ASSERT_THROW(_tx_dsps.has_key(name));
         val = _tx_dsps[name].get_link();
         return;
 
@@ -154,36 +206,73 @@ void usrp2_impl::mboard_get(const wax::obj &key_, wax::obj &val){
  * MBoard Set Properties
  **********************************************************************/
 void usrp2_impl::mboard_set(const wax::obj &key, const wax::obj &val){
+    //handle the other props
+    if (key.type() == typeid(std::string)){
+        if (key.as<std::string>() == "mac-addr"){
+            //setup the out data
+            usrp2_ctrl_data_t out_data;
+            out_data.id = htonl(USRP2_CTRL_ID_HERE_IS_A_NEW_MAC_ADDR_BRO);
+            mac_addr_t mac_addr(val.as<std::string>());
+            std::memcpy(out_data.data.mac_addr, &mac_addr, sizeof(mac_addr_t));
+
+            //send and recv
+            usrp2_ctrl_data_t in_data = ctrl_send_and_recv(out_data);
+            ASSERT_THROW(htonl(in_data.id) == USRP2_CTRL_ID_THIS_IS_MY_MAC_ADDR_DUDE);
+            return;
+        }
+
+        if (key.as<std::string>() == "ip-addr"){
+            //setup the out data
+            usrp2_ctrl_data_t out_data;
+            out_data.id = htonl(USRP2_CTRL_ID_HERE_IS_A_NEW_IP_ADDR_BRO);
+            out_data.data.ip_addr = htonl(boost::asio::ip::address_v4::from_string(val.as<std::string>()).to_ulong());
+
+            //send and recv
+            usrp2_ctrl_data_t in_data = ctrl_send_and_recv(out_data);
+            ASSERT_THROW(htonl(in_data.id) == USRP2_CTRL_ID_THIS_IS_MY_IP_ADDR_DUDE);
+            return;
+        }
+    }
+
     //handle the get request conditioned on the key
-    switch(wax::cast<mboard_prop_t>(key)){
+    switch(key.as<mboard_prop_t>()){
 
     case MBOARD_PROP_PPS_SOURCE:{
-            std::string name = wax::cast<std::string>(val);
-            ASSERT_THROW(_pps_source_dict.has_key(name));
+            std::string name = val.as<std::string>();
+            assert_has(_pps_source_dict.get_keys(), name, "usrp2 pps source");
             _pps_source = name; //shadow
             update_clock_config();
         }
         return;
 
     case MBOARD_PROP_PPS_POLARITY:{
-            std::string name = wax::cast<std::string>(val);
-            ASSERT_THROW(_pps_polarity_dict.has_key(name));
+            std::string name = val.as<std::string>();
+            assert_has(_pps_polarity_dict.get_keys(), name, "usrp2 pps polarity");
             _pps_polarity = name; //shadow
             update_clock_config();
         }
         return;
 
     case MBOARD_PROP_REF_SOURCE:{
-            std::string name = wax::cast<std::string>(val);
-            ASSERT_THROW(_ref_source_dict.has_key(name));
+            std::string name = val.as<std::string>();
+            assert_has(_ref_source_dict.get_keys(), name, "usrp2 reference source");
             _ref_source = name; //shadow
             update_clock_config();
         }
         return;
 
+    case MBOARD_PROP_TIME_NOW:{
+        set_time_spec(val.as<time_spec_t>(), true);
+        return;
+    }
+
+    case MBOARD_PROP_TIME_NEXT_PPS:{
+        set_time_spec(val.as<time_spec_t>(), false);
+        return;
+    }
+
     case MBOARD_PROP_NAME:
     case MBOARD_PROP_OTHERS:
-    case MBOARD_PROP_MTU:
     case MBOARD_PROP_CLOCK_RATE:
     case MBOARD_PROP_RX_DSP:
     case MBOARD_PROP_RX_DSP_NAMES:
@@ -195,8 +284,6 @@ void usrp2_impl::mboard_set(const wax::obj &key, const wax::obj &val){
     case MBOARD_PROP_TX_DBOARD_NAMES:
     case MBOARD_PROP_PPS_SOURCE_NAMES:
     case MBOARD_PROP_REF_SOURCE_NAMES:
-    case MBOARD_PROP_TIME_NOW:
-    case MBOARD_PROP_TIME_NEXT_PPS:
         throw std::runtime_error("Error: trying to set read-only property on usrp2 mboard");
 
     }
diff --git a/host/lib/usrp/usrp2/usrp2_impl.cpp b/host/lib/usrp/usrp2/usrp2_impl.cpp
index 5aa5d6e8d..e1371a094 100644
--- a/host/lib/usrp/usrp2/usrp2_impl.cpp
+++ b/host/lib/usrp/usrp2/usrp2_impl.cpp
@@ -23,6 +23,12 @@
 
 using namespace uhd;
 using namespace uhd::usrp;
+using namespace uhd::transport;
+namespace asio = boost::asio;
+
+STATIC_BLOCK(register_usrp2_device){
+    device::register_device(&usrp2::discover, &usrp2::make);
+}
 
 /***********************************************************************
  * Discovery over the udp transport
@@ -30,30 +36,26 @@ using namespace uhd::usrp;
 uhd::device_addrs_t usrp2::discover(const device_addr_t &hint){
     device_addrs_t usrp2_addrs;
 
+    if (not hint.has_key("addr")) return usrp2_addrs;
+
     //create a udp transport to communicate
     //TODO if an addr is not provided, search all interfaces?
     std::string ctrl_port = boost::lexical_cast<std::string>(USRP2_UDP_CTRL_PORT);
-    transport::udp::sptr udp_transport = \
-        transport::udp::make(hint["addr"], ctrl_port, true);
+    udp_simple::sptr udp_transport = udp_simple::make_broadcast(
+        hint["addr"], ctrl_port
+    );
 
     //send a hello control packet
     usrp2_ctrl_data_t ctrl_data_out;
     ctrl_data_out.id = htonl(USRP2_CTRL_ID_GIVE_ME_YOUR_IP_ADDR_BRO);
     udp_transport->send(boost::asio::buffer(&ctrl_data_out, sizeof(ctrl_data_out)));
 
-    //loop and recieve until the time is up
-    size_t num_timeouts = 0;
+    //loop and recieve until the timeout
     while(true){
         usrp2_ctrl_data_t ctrl_data_in;
-        size_t len = udp_transport->recv(
-            boost::asio::buffer(&ctrl_data_in, sizeof(ctrl_data_in))
-        );
+        size_t len = udp_transport->recv(asio::buffer(&ctrl_data_in, sizeof(ctrl_data_in)));
         //std::cout << len << "\n";
-        if (len < sizeof(usrp2_ctrl_data_t)){
-            //sleep a little so we dont burn cpu
-            if (num_timeouts++ > 50) break;
-            boost::this_thread::sleep(boost::posix_time::milliseconds(1));
-        }else{
+        if (len >= sizeof(usrp2_ctrl_data_t)){
             //handle the received data
             switch(ntohl(ctrl_data_in.id)){
             case USRP2_CTRL_ID_THIS_IS_MY_IP_ADDR_DUDE:
@@ -61,12 +63,14 @@ uhd::device_addrs_t usrp2::discover(const device_addr_t &hint){
                 boost::asio::ip::address_v4 ip_addr(ntohl(ctrl_data_in.data.ip_addr));
                 device_addr_t new_addr;
                 new_addr["name"] = "USRP2";
-                new_addr["type"] = "usrp2";
+                new_addr["transport"] = "udp";
                 new_addr["addr"] = ip_addr.to_string();
                 usrp2_addrs.push_back(new_addr);
-                break;
+                //dont break here, it will exit the while loop
+                //just continue on to the next loop iteration
             }
         }
+        if (len == 0) break; //timeout
     }
 
     return usrp2_addrs;
@@ -75,16 +79,18 @@ uhd::device_addrs_t usrp2::discover(const device_addr_t &hint){
 /***********************************************************************
  * Make
  **********************************************************************/
-#define num2str(num) (boost::lexical_cast<std::string>(num))
+template <class T> std::string num2str(T num){
+    return boost::lexical_cast<std::string>(num);
+}
 
 device::sptr usrp2::make(const device_addr_t &device_addr){
     //create a control transport
-    transport::udp::sptr ctrl_transport = transport::udp::make(
+    udp_simple::sptr ctrl_transport = udp_simple::make_connected(
         device_addr["addr"], num2str(USRP2_UDP_CTRL_PORT)
     );
 
     //create a data transport
-    transport::udp::sptr data_transport = transport::udp::make(
+    udp_zero_copy::sptr data_transport = udp_zero_copy::make(
         device_addr["addr"], num2str(USRP2_UDP_DATA_PORT)
     );
 
@@ -98,8 +104,8 @@ device::sptr usrp2::make(const device_addr_t &device_addr){
  * Structors
  **********************************************************************/
 usrp2_impl::usrp2_impl(
-    transport::udp::sptr ctrl_transport,
-    transport::udp::sptr data_transport
+    udp_simple::sptr ctrl_transport,
+    udp_zero_copy::sptr data_transport
 ){
     _ctrl_transport = ctrl_transport;
     _data_transport = data_transport;
@@ -132,9 +138,8 @@ usrp2_impl::usrp2_impl(
     //init the tx and rx dboards (do last)
     dboard_init();
 
-    //send a small data packet so the usrp2 knows the udp source port
-    uint32_t zero_data = 0;
-    _data_transport->send(boost::asio::buffer(&zero_data, sizeof(zero_data)));
+    //init the send and recv io
+    io_init();
 
 }
 
@@ -160,24 +165,15 @@ usrp2_ctrl_data_t usrp2_impl::ctrl_send_and_recv(const usrp2_ctrl_data_t &out_da
     out_copy.seq = htonl(++_ctrl_seq_num);
     _ctrl_transport->send(boost::asio::buffer(&out_copy, sizeof(usrp2_ctrl_data_t)));
 
-    //loop and recieve until the time is up
-    size_t num_timeouts = 0;
+    //loop until we get the packet or timeout
     while(true){
         usrp2_ctrl_data_t in_data;
-        size_t len = _ctrl_transport->recv(
-            boost::asio::buffer(&in_data, sizeof(in_data))
-        );
-        if (len < sizeof(usrp2_ctrl_data_t)){
-            //sleep a little so we dont burn cpu
-            if (num_timeouts++ > 50) break;
-            boost::this_thread::sleep(boost::posix_time::milliseconds(1));
-        }else{
-            //handle the received data
-            if (ntohl(in_data.seq) == _ctrl_seq_num){
-                return in_data;
-            }
-            //didnt get seq, continue on...
+        size_t len = _ctrl_transport->recv(asio::buffer(&in_data, sizeof(in_data)));
+        if (len >= sizeof(usrp2_ctrl_data_t) and ntohl(in_data.seq) == _ctrl_seq_num){
+            return in_data;
         }
+        if (len == 0) break; //timeout
+        //didnt get seq or bad packet, continue looking...
     }
     throw std::runtime_error("usrp2 no control response");
 }
@@ -190,18 +186,28 @@ void usrp2_impl::get(const wax::obj &key_, wax::obj &val){
     boost::tie(key, name) = extract_named_prop(key_);
 
     //handle the get request conditioned on the key
-    switch(wax::cast<device_prop_t>(key)){
+    switch(key.as<device_prop_t>()){
     case DEVICE_PROP_NAME:
         val = std::string("usrp2 device");
         return;
 
     case DEVICE_PROP_MBOARD:
+        ASSERT_THROW(_mboards.has_key(name));
         val = _mboards[name].get_link();
         return;
 
     case DEVICE_PROP_MBOARD_NAMES:
         val = prop_names_t(_mboards.get_keys());
         return;
+
+    case DEVICE_PROP_MAX_RX_SAMPLES:
+        val = size_t(_max_rx_samples_per_packet);
+        return;
+
+    case DEVICE_PROP_MAX_TX_SAMPLES:
+        val = size_t(_max_tx_samples_per_packet);
+        return;
+
     }
 }
 
diff --git a/host/lib/usrp/usrp2/usrp2_impl.hpp b/host/lib/usrp/usrp2/usrp2_impl.hpp
index 9a4c42d42..fc713c2bf 100644
--- a/host/lib/usrp/usrp2/usrp2_impl.hpp
+++ b/host/lib/usrp/usrp2/usrp2_impl.hpp
@@ -22,7 +22,9 @@
 #include <boost/thread.hpp>
 #include <boost/shared_ptr.hpp>
 #include <boost/function.hpp>
-#include <uhd/transport/udp.hpp>
+#include <uhd/transport/vrt.hpp>
+#include <uhd/transport/udp_simple.hpp>
+#include <uhd/transport/udp_zero_copy.hpp>
 #include <uhd/usrp/dboard_manager.hpp>
 #include "fw_common.h"
 
@@ -81,8 +83,8 @@ public:
      * \param data_transport the udp transport for data
      */
     usrp2_impl(
-        uhd::transport::udp::sptr ctrl_transport,
-        uhd::transport::udp::sptr data_transport
+        uhd::transport::udp_simple::sptr ctrl_transport,
+        uhd::transport::udp_zero_copy::sptr data_transport
     );
 
     ~usrp2_impl(void);
@@ -98,18 +100,32 @@ public:
     double get_master_clock_freq(void);
 
     //the io interface
-    size_t send(const boost::asio::const_buffer &, const uhd::metadata_t &, const std::string &);
-    size_t recv(const boost::asio::mutable_buffer &, uhd::metadata_t &, const std::string &);
+    size_t send(const boost::asio::const_buffer &, const uhd::tx_metadata_t &, const std::string &);
+    size_t recv(const boost::asio::mutable_buffer &, uhd::rx_metadata_t &, const std::string &);
 
 private:
     //the raw io interface (samples are in the usrp2 native format)
-    size_t send_raw(const boost::asio::const_buffer &, const uhd::metadata_t &);
-    size_t recv_raw(const boost::asio::mutable_buffer &, uhd::metadata_t &);
-    uhd::dict<uint32_t, size_t> _stream_id_to_packet_seq;
+    void recv_raw(uhd::rx_metadata_t &);
+    uhd::dict<uint32_t, size_t> _tx_stream_id_to_packet_seq;
+    uhd::dict<uint32_t, size_t> _rx_stream_id_to_packet_seq;
+    static const size_t _mtu = 1500; //FIXME we have no idea
+    static const size_t _hdrs = (2 + 14 + 20 + 8); //size of headers (pad, eth, ip, udp)
+    static const size_t _max_rx_samples_per_packet =
+        (_mtu - _hdrs)/sizeof(uint32_t) -
+        USRP2_HOST_RX_VRT_HEADER_WORDS32 -
+        USRP2_HOST_RX_VRT_TRAILER_WORDS32
+    ;
+    static const size_t _max_tx_samples_per_packet =
+        (_mtu - _hdrs)/sizeof(uint32_t) -
+        uhd::transport::vrt::max_header_words32
+    ;
+    uhd::transport::smart_buffer::sptr _rx_smart_buff;
+    boost::asio::const_buffer _rx_copy_buff;
+    void io_init(void);
 
     //udp transports for control and data
-    uhd::transport::udp::sptr _ctrl_transport;
-    uhd::transport::udp::sptr _data_transport;
+    uhd::transport::udp_simple::sptr _ctrl_transport;
+    uhd::transport::udp_zero_copy::sptr _data_transport;
 
     //private vars for dealing with send/recv control
     uint32_t _ctrl_seq_num;
@@ -119,6 +135,7 @@ private:
     std::string _pps_source, _pps_polarity, _ref_source;
     void init_clock_config(void);
     void update_clock_config(void);
+    void set_time_spec(const uhd::time_spec_t &time_spec, bool now);
 
     //mappings from clock config strings to over the wire enums
     uhd::dict<std::string, usrp2_pps_source_t>   _pps_source_dict;