usrp2: added notes on multiple device network setup, improved warnings for buff size stuff

3 files changed, 41 insertions, 11 deletions

diff --git a/host/docs/usrp2.rst b/host/docs/usrp2.rst
index d3ae1dec7..76b27fd31 100644
--- a/host/docs/usrp2.rst
+++ b/host/docs/usrp2.rst
@@ -88,7 +88,7 @@ Setup the host interface
 The USRP2 communicates at the IP/UDP layer over the gigabit ethernet.
 The default IP address of the USRP2 is **192.168.10.2**
 You will need to configure the host's ethernet interface with a static IP address to enable communication.
-An address of **192.168.10.1** is recommended.
+An address of **192.168.10.1** and a subnet mask of **255.255.255.0** is recommended.
 
 **Note:**
 When using the UHD, if an IP address for the USRP2 is not specified,
@@ -97,6 +97,26 @@ On some systems, the firewall will block UDP broadcast packets.
 It is recommended that you change or disable your firewall settings. 
 
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+Multiple device configuration
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+As described above, you will need one ethernet interface per USRP2.
+Each ethernet interface should have its own subnet,
+and the corresponding USRP2 device should be assigned an address in that subnet.
+Example:
+
+**Configuration for USRP2 device 0:**
+
+* Ethernet interface IPv4 address: 192.168.10.1
+* Ethernet interface subnet mask: 255.255.255.0
+* USRP2 device IPv4 address: 192.168.10.2
+
+**Configuration for USRP2 device 1:**
+
+* Ethernet interface IPv4 address: 192.168.20.1
+* Ethernet interface subnet mask: 255.255.255.0
+* USRP2 device IPv4 address: 192.168.20.2
+
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 Change the USRP2's IP address
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 You may need to change the USRP2's IP address for several reasons:
@@ -122,7 +142,7 @@ Run the following commands:
 ::
 
     cd <prefix>/share/uhd/utils
-    ./usrp2_recovery.py --ifc=eth0 --new-ip=192.168.10.3
+    sudo ./usrp2_recovery.py --ifc=eth0 --new-ip=192.168.10.3
 
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 Debugging networking problems
@@ -181,7 +201,6 @@ The device address string representation for 2 USRP2s with IPv4 addresses 192.16
 
     addr=192.168.10.2 192.168.20.2
 
-
 ------------------------------------------------------------------------
 Resize the send and receive buffers
 ------------------------------------------------------------------------
diff --git a/host/lib/transport/udp_zero_copy_asio.cpp b/host/lib/transport/udp_zero_copy_asio.cpp
index 86ea275c1..e3f3ef5bf 100644
--- a/host/lib/transport/udp_zero_copy_asio.cpp
+++ b/host/lib/transport/udp_zero_copy_asio.cpp
@@ -155,17 +155,17 @@ template<typename Opt> static void resize_buff_helper(
         else std::cout << boost::format(
             "Current %s sock buff size: %d bytes"
         ) % name % actual_size << std::endl;
+        if (actual_size < target_size) std::cerr << boost::format(
+            "Warning:\n"
+            "    The %s buffer is smaller than the requested size.\n"
+            "    The minimum recommended buffer size is %d bytes.\n"
+            "    See the USRP2 application notes on buffer resizing.\n"
+        ) % name % MIN_SOCK_BUFF_SIZE << std::endl;
     }
 
     //otherwise, ensure that the buffer is at least the minimum size
     else if (udp_trans->get_buff_size<Opt>() < MIN_SOCK_BUFF_SIZE){
         resize_buff_helper<Opt>(udp_trans, MIN_SOCK_BUFF_SIZE, name);
-        if (udp_trans->get_buff_size<Opt>() < MIN_SOCK_BUFF_SIZE){
-            std::cerr << boost::format(
-                "Warning: the %s buffer size is smaller than the recommended size of %d bytes.\n"
-                "    See the USRP2 application notes on buffer resizing."
-            ) % name % MIN_SOCK_BUFF_SIZE << std::endl;
-        }
     }
 }
 
diff --git a/host/lib/usrp/usrp2/usrp2_impl.cpp b/host/lib/usrp/usrp2/usrp2_impl.cpp
index 9d1ac991f..02f53bc69 100644
--- a/host/lib/usrp/usrp2/usrp2_impl.cpp
+++ b/host/lib/usrp/usrp2/usrp2_impl.cpp
@@ -127,14 +127,25 @@ static uhd::device_addrs_t usrp2_find(const device_addr_t &hint){
 /***********************************************************************
  * Make
  **********************************************************************/
+template <typename out_type, typename in_type>
+out_type lexical_cast(const in_type &in){
+    try{
+        return boost::lexical_cast<out_type>(in);
+    }catch(...){
+        throw std::runtime_error(str(boost::format(
+            "failed to cast \"%s\" to type \"%s\""
+        ) % boost::lexical_cast<std::string>(in) % typeid(out_type).name()));
+    }
+}
+
 static device::sptr usrp2_make(const device_addr_t &device_addr){
     //extract the receive and send buffer sizes
     size_t recv_buff_size = 0, send_buff_size= 0 ;
     if (device_addr.has_key("recv_buff_size")){
-        recv_buff_size = size_t(boost::lexical_cast<double>(device_addr["recv_buff_size"]));
+        recv_buff_size = size_t(lexical_cast<double>(device_addr["recv_buff_size"]));
     }
     if (device_addr.has_key("send_buff_size")){
-        send_buff_size = size_t(boost::lexical_cast<double>(device_addr["send_buff_size"]));
+        send_buff_size = size_t(lexical_cast<double>(device_addr["send_buff_size"]));
     }
 
     //create a ctrl and data transport for each address