W5300 High-capacity data communication

Question

Hello. TCP server mode, RX_FIFO size2k。 200 Mbytes of data are received from the PC, but “TCP ZeroWindow” occurs when receiving about 100 Mbytes, error stops with “RST”. What kind of things can be considered? Please give me advice

Eugeny · Answer

Share wireshark log. “TCP zero window” will happen after receiving first 2k if you do not flush data from RX buffers.

tnk · Answer

Thank you for the e-mail. We incorporate W5300 in the receiver of the printer. Below is the contents checked here. Reading from R_FIFO is executed by DMA. //SOCK_ESTABLISHED: Receive if((len=getSn_RX_RSR(s)) > 0) // check the size of received data { // Test200M data len = recv(s,ep3_rxdat,len); // Datalength Read //DMA Dest set HeadAdr = (unsigned long)&FIFOW_0; //DMA dma_EthFIFOtoEgnFIFO_eth(len/2); //Read Only DumyData Send if(getSn_RX_RSR(s) == 0) // check if the window size is full or not { /* Sn_RX_RSR can be compared with another value instead of ??0??, according to the host performance of receiving data */ setSn_TX_WRSR(s,1); // size : 1 byte dummy size setSn_TX_FIFOR(s,0x00); setSn_CR(s,Sn_CR_SEND); // send while(!(getSn_IR(s) & Sn_IR_SENDOK)); // wait SEND command completion setSn_IR(s,Sn_IR_SENDOK); // clear Sn_IR_SENDOK bit } } } break; *Wireshark Error PC:192.168.0.10 W5300:192.1680.3 Overall data amount PC spool: 200 Mbytes Error occurrence: Approximately 100 Mbytes PC⇒zerowindowprob W5300:no replay PC⇒RST Why does W5300 not respond? NGError1280×800 168 KB Thank you in advance.

Eugeny · Answer

The cause of the problem is not W5300, it is your PC. You continuously send one byte to PC from W5300, and PC does not read it from its RX queue. Screenshot shows that PC has window size 4, then 3, then 2, then 1, and finally 0, and next write from W5300 to PC goes nowhere, so PC resets the connection shortly as communication looks broken.

tnk · Answer

Hello. I investigated PC window size. os: window 7 98 M / 200 Mbytes received. Initial value: 64200 Dummy data (ACK) from W 5300 1 byte Receive every -1 os: window 10 180 M / 200 Mbytes received. Initial value: 64200 Dummy data (ACK) from W 5300 1 byte Receive every -1 It returns to the initial value on the way and then -1 after receiving the data. I decided it was not a problem of W5300 but a problem of PC side. I was rude in an unclear English sentence. (I am Japanese.) Please also take a consultation.

tnk · Answer

Dear Great Contributor. I can’t change TCPiPapps in my PC To fix PC Window size, I tried to 0bytes ack data from w5300. setSn_TX_WRSR(s,0); // size :0 byte dummy size setSn_TX_FIFO(s,0x0000) Wiresharklog 175kbytes/200Mbytes 192.168.0.3(w5300) ZeroWindow err07051280×800 155 KB What is the purpose of dummy size transfer? What is the difference between dummy size 0 and dummy size 1? Why does zerowindow occur in dummy size 0 ? Best regards

Eugeny · Answer

tnk: 192.168.0.3(w5300) ZeroWindow You can see in wireshark packet #43 that it reports W5300 window size as 0. The situation simply means that W5300 stopped getting data from its RX buffers. Check your program driving W5300. tnk: What is the purpose of dummy size transfer? What is the difference between dummy size 0 and dummy size 1? What is this “dummy size”? Using TCP you do should not send anything if it is not required by protocol. Does your protocol require sending these bytes? tnk: Why does zerowindow occur in dummy size 0 ? Because now it is W5300 which stops clearing its RX buffer.

tnk · Answer

Dear Great Contributor. What is this “dummy size”? Using TCP you do should not send anything if it is >not required by protocol. Does your protocol require sending these bytes? The following is the TX transfer size. setSn_TX_WRSR(s,0); // size :0 byte dummy size setSn_TX_WRSR(s,1); // size :1 byte dummy size Best regards

tnk · Answer

Dear Eugeny Attached log is basic, flow and please tell me at the timing of a reply of ACK of W5300. %E3%83%87%E3%83%BC%E3%82%BF%E6%B5%81%E3%82%8C%E7%A2%BA%E8%AA%8D1280×800 176 KB No.7,9,24 send the window-update packet when the window size is full *Please tell me at the timing of a reply of No.11,13,15,17,19,21. Best regards

Eugeny · Answer

tnk: please tell me at the timing of a reply of ACK of W5300. Not sure what you want to know about this picture. It just shows that IP address 10 connects to IP address 3, sends some data and then closes connection, and IP address 3 confirms the end of session. There seem to be no issue in the communication. The only strange thing is IP address 3 having PSH flag set in its ACK packets.

tnk · Answer

Dear Eugeny IP address

tnk · Answer

Dear Eugeny IP address10:PC IP address3:W5300 No.6 192.168.0.10 192.168.0.3 TCP 2974 [ACK] Seq=1 Ack=1 Win=64240 Len=2920 No.7 192.168.0.3 192.168.0.10 TCP 60 [PSH,ACK] Seq=2921 Ack=1 Win=10238 Len=1 Under the condition of (Sn_Rx_RSR==0) we can understand that IP address3 sends [PSH,ACK] to IP address10. The question is the condition of W5300 transferring [PSH,ACK] from IP address3 to IP address10 in the transfer below. No.10 192.168.0.10 192.168.0.3 TCP 10274 [ACK] Seq=8761 Ack=3 Win=64238 Len=10220 No.11 192.168.0.3 192.168.0.10 TCP 60 [PSH,ACK] Seq=3 Ack=18981 Win=10238 Len=0 Best regards

Eugeny · Answer

tnk: Under the condition of (Sn_Rx_RSR==0) we can understand that IP address3 sends [PSH,ACK] to IP address10. Where did you see this condition from this Wireshark log? tnk: The question is the condition of W5300 transferring [PSH,ACK] from IP address3 to IP address10 in the transfer below. What is your problem with this TCP/IP session? What are you trying to find in it? For me another strange thing in the output is that W5300 is explicitly saying that it wants MSS=1460, but another device sends packets of 10KB in size. You must: explain why this log is important for you and what you want to see in it; attach this log, bit only picture of it.

tnk · Answer

Dear Eugeny Where did you see this condition from this Wireshark log? It corresponds to the length of DumyData of Window size update in the reading process of the data receive buffer of W5300. setSn_TX_WRSR(s,1); // size :1 byte dummy size setSn_TX_FIFO(s,0x0000) 1.explain why this log is important for you and what you want to see in it; I use it with read only. I am investigating ways to not subtract Window Size of IP address10. I want to know how flow control is done. Best regards

tnk · Answer

Dear Eugeny \file socket.c Implemetation of WIZnet SOCKET API fucntions uint32 recv(SOCKET s, uint8 * buf, uint32 len) { setSn_CR(s,Sn_CR_RECV); // recv /* \warning send a packet for updating window size. This code block must be only used when W5300 do only receiving data. */ // ------------------------ // WARNING CODE BLOCK START // M_04072008 : Replace Sn_CR_SEND_KEP with Sn_CR_SEND. ①//if(getSn_RX_RSR(s) == 0) // send the window-update packet when the window size is full //{ // uint8 keep_time = 0; // if((keep_time=getSn_KPALVTR(s)) != 0x00) setSn_KPALVTR(s,0x00); // disables the auto-keep-alive-process // setSn_CR(s,Sn_CR_SEND_KEEP); // send a keep-alive packet by command // setSn_KPALVTR(s,keep_time); // restore the previous keep-alive-timer value //} ②// if(getSn_RX_RSR(s) == 0) // check if the window size is full or not // { /* Sn_RX_RSR can be compared with another value instead of ==0, // according to the host performance of receiving data */ // setSn_TX_WRSR(s,1); // size : 1 byte dummy size // IINCHIP_WRITE(Sn_TX_FIFOR(s),0x0000); // write dummy data into tx memory // setSn_CR(s,Sn_CR_SEND); // send // while(!(getSn_IR(s) & Sn_IR_SENDOK)); // wait SEND command completion // setSn_IR(s,Sn_IR_SENDOK); // clear Sn_IR_SENDOK bit // } //｝ ● Please tell me the difference between ① and ② in processing after receiving w5300 data. ● When ① is executed, normal transfer can not be performed. What do you think? ● How can I determine the comment of ②, the setting value of "another value instead of ==0" ? Best regards

tnk · Answer

Dear midnigtcow I use it with ReceiveOnly. Transfer 1 Gbytes of data from the PC as one document. ZeroWindow Error on the PC side is occurring. When it is W5300 ReadOnly Mode, it is necessary to send 1 bytedummy, so in PC it is necessary to read 1 bytedummy? thank you.

tnk · Answer

Dear midnigtcow In the case of ReceiveOnly, it does not conform to protocol standards such as OSI. thank you.

tnk · Answer

Dear midnigtcow When tried by the method of ①, is it necessary to change W5300’s COMMONreg, SOCKETreg etc? We build a program with reference to W5300_Drv_V1.2.5. Thank you.