Thanks very much Activecat I have some last questions please : 1- Does the block " Socket PDU" can be used instead of a socket ? It don't understand what is the importance of this block ? what does it take as input ? I know it takes "Pdus"= "Async message " but also I don't understand what is the block that must precedes the socket PDU.
2- Do I have to write a code for socket ?or simply I can write ,in the "UDP source" block in Gnu radio(2nd lap) , the IP address & port number of the Ethernet connection (of 2nd lap) receiving from Twinkle(1st lap) ? Or the UDP source is an interface to socket and So there must exist an external code of socket ? Thanks in advance 2014-06-21 19:43 GMT+03:00 Activecat <active...@gmail.com>: > On Sat, Jun 21, 2014 at 7:31 PM, Sara Chérif <saracheri...@gmail.com> > wrote: > >> Thanks Marcus Müller , Marcus D. Leech , Activecat. >> >> yes , we can call this "Ethernet to wireless bridge using GSM RF channel >> ". I have some questions, please : >> >> 1- Can I use both UDP source & TCP source in this way : >> Can I connect output of" UDP source" & output of "TCP source" to input >> of "Socket PDU " and connect output of "Socket PDU " to the input of the >> "PDU to tagged stream " block ? What is wrong in this connection ? >> >> 2- But when I connect the output of TCP or UDP source to the Socket PDU , >> I got an error ! what does the Socket PDU block take as an input?! >> >> 3- Also when I connect output of "TCP or UDP source" to "PDU to tagged >> stream " I got an error , what must be the input of the PDU to tagged >> stream block ?! Does the "PDU to tagged stream " is used here instead of >> the "stream to tagged stream" block and has same role? >> >> >> 4- Does the block " Socket PDU" can be used instead of a socket ? It >> don't understand what is the importance of this block ? >> >> 5- Is there any flags so that when signaling packets are coming (SIP or >> ARP) : TCP source is enabled while UDP source is disabled ? >> And the inverse happens when there is RTP packets coming? >> Note that , in network settings in Twinkle soft phone , there is a port >> number for RTP different from port number of SIP & we can change these >> ports numbers , I don't know if this may help me . >> >> 6- Do I have to write a code for socket ?or simply I can write ,in the >> "UDP source" block in Gnu radio(2nd lap) , the IP address & port number of >> the Ethernet connection (of 2nd lap) receiving from Twinkle(1st lap) ? >> >> 7- If there is no new packets coming , I want to send zeros instead of >> repeating the sent packets ? How Can I do this ? >> i.e: I want to insert 8 bits zeros after each ofdm symbol as a guard band >> : I tried to insert " pad source " block to do this , after the IFFT block >> and before the cyclic prefixer block >> , but it is not allowed to connect 2 inputs to the cyclic prefixer also >> I don't know how to use the pad source to insert these zeros & I don't know >> if there is a block to concatenate between the zeros coming from the pad >> source & the output of the ifft block . >> >> Thanks in advance . >> > > > Looking at above questions, you doesn't seem to understand OSI 7 layers > model. > > You said this is a "wireless bridge". > If you have decided to have gnuradio (with USRPs) working at layer 2, then > you no longer need to consider TCP, UDP, RTP etc. > Even if you decided to have gnuradio working at layer 3, you also no need > to handle TCP, UDP, RTP etc. > > If you want to have gnuradio (with USRPs) working at layer 7, then you > this will be very complicated and the resulting setup will be very > application specific, i.e. you will need to handle each application one by > one. This approach is unnecessarily complicated and hence not recommended. > > > > An analogue to this: > > Says, now you have a PC that you want to connect to internet. In another > room you have a DSL router which is already connected to internet. > Currently the PC has no connection to the DSL router, it is standalone. > To connect the PC to the DSL router, you have few options: > > Option 1: Use Ethernet Extender > The Externet Extender do not need to understand any IP address, TCP, UDP, > HTTP etc. > In this case the Ethernet Extender is working at OSI layer 1. The > Ethernet Extender doesn't even need to care about the MAC address, right ? > > Option 2: Use a bridge > The bridge need a MAC address but does not need any IP address. It will > perform packet switching based on MAC addresses. It doesn't need to look at > the IP addresses of the packets, no need to talk about the TCP, HTML etc. > In this case the bridge is working at OSI layer 2. > > Option 3: Use a router > If the IP address of your PC is in different subnet from the Ethernet port > of the DSL router, then you need put another router between the PC and the > DSL router. The default gateway of the PC is pointing to the > interconnecting router. > In this case the router is working at OSI layer 3. The router doesn't > need to understand any HTTP protocol, right? > > Option 4: Use a proxy server > The HTTP proxy server needs to understand HTTP traffic, know the contents > of each website etc in order to perform filtering and caching. In this > case the proxy server is working at OSI layer 7. > > > Now let's come back to your question. > As you already decided to have gnuradio working at layer 2, why you still > need to care about the UDP, TCP, RTP etc ? >
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