The landscape of high-speed data transmission is in a constant state of evolution, as new technologies emerge to meet the ever-growing demands of bandwidth-intensive applications. While the User Datagram Protocol (UDP) has been the preferred protocol for streaming data for GigE Vision cameras due to its efficient streaming performance and simplicity, it has limitations when it comes to flow control and packet retransmissions on higher Ethernet bandwidth cameras such as 10GigE and 25Gige cameras. Remote Direct Memory Access (RDMA) is a viable alternative for high bandwidth, multi-camera applications, offering a more robust and efficient data transmission method. RDMA bypasses the CPU and operating system to store image data directly onto the host PC’s memory, making it the ideal choice for managing large amounts of data in modern high-bandwidth Ethernet camera applications.
The current implementation of UDP for GigE Vision was designed for 1 GigE bandwidth, and the reliability features missing from UDP are built into the GigE Vision standard at the application layer. This means the OS and CPU must monitor and manage the data stream for missing packets and interrupt the camera to retransmit missing packets. At 1 GigE speeds, host PC resources needed to monitor and resend dropped packets are readily available. However, for higher bandwidth cameras RDMA offers a better solution by enabling data movement between devices on a network without any CPU involvement on a per-packet basis. By implementing RDMA, network adapters can write data directly into the host PC’s main memory, bypassing the operating system entirely, and reducing CPU overhead.