Data loss occurs when using TCP to send data on the nRF7002 DK.

RE: Data loss occurs when using TCP to send data on the nRF7002 DK.

Benjamin — Tue, 06 Jan 2026 11:22:04 GMT

Hi,

I had a look at your code. The reason is that the send function may send fewer bytes than requested. This is normal behavior when working with TCP. TCP is a byte stream protocol, so partial sends are expected. It is correct to repeatedly call send until all data has been sent, as you’ve done in the second function.

Regards,
Benjamin

RE: Data loss occurs when using TCP to send data on the nRF7002 DK.

Ziyao Zhou — Tue, 06 Jan 2026 02:13:33 GMT

[deleted]

RE: Data loss occurs when using TCP to send data on the nRF7002 DK.

Benjamin — Mon, 05 Jan 2026 15:47:59 GMT

[deleted]

RE: Data loss occurs when using TCP to send data on the nRF7002 DK.

Ziyao Zhou — Tue, 30 Dec 2025 01:45:30 GMT

Hi,

ChatGPT ask me to change cam send

from

void cam_send(const void *buf, size_t len){
		#if defined(CONFIG_SAMPLE_SCOKET_TCP)
			if (send(tcp_server_socket, buf, len, 0) == -1) {
				perror("Sending failed");
				close(tcp_server_socket);
				FATAL_ERROR();
				return;
			}
		#else
			sendto(udp_socket, buf, len, 0, (struct sockaddr *)&pc_addr,  sizeof(pc_addr));
		#endif
}

void cam_send(const void *buf, size_t len){
    #if defined(CONFIG_SAMPLE_SCOKET_TCP)
        size_t total_sent = 0;
        int retry_count = 0;
        const int MAX_RETRIES = 3;
        
        while (total_sent < len && retry_count < MAX_RETRIES) {
            ssize_t sent = send(tcp_server_socket,
                               (uint8_t*)buf + total_sent,
                               len - total_sent, 0);
            if (sent == -1) {
                if (errno == EAGAIN || errno == EWOULDBLOCK) {
                    // 缓冲区满，稍后重试
                    k_sleep(K_MSEC(10));
                    retry_count++;
                    continue;
                }
                // 其他错误，连接断开
                perror("Sending failed");
                close(tcp_server_socket);
                return;
            }
            total_sent += sent;
            retry_count = 0; // 成功发送后重置重试计数
        }
        
        if (total_sent < len) {
            LOG_ERR("Failed to send all data after retries");
        }
    #else
        sendto(udp_socket, buf, len, 0, (struct sockaddr *)&pc_addr, sizeof(pc_addr));
    #endif
}

The the data loss will be sloved. But I am not so sure about why this will work.

RE: Data loss occurs when using TCP to send data on the nRF7002 DK.

Benjamin — Tue, 23 Dec 2025 10:17:55 GMT

Hi Zhou,

Thanks for reaching out, we are currently understaffed due to Christmas holidays. Answers may take longer.

I am starting to look into this, we'll come back to you when I have an update.

Best regards,
Benjamin