Bumping up bandwidth

The theory goes that the demand for bandwidth and increasing network speeds will ultimately overwhelm the processing power and memory bandwidth of your average PC and other network components.

Our Technology Update this week takes a look at a technology that promises to help alleviate this issue: Remote Direct Memory Access (RDMA)

RDMA defines how one computer can directly place information in the another computers’ memory with minimal demands on memory bus bandwidth and CPU processing overhead. RDMA over TCP/IP defines the interoperable protocols to support RDMA operations over standard TCP/IP networks.

According to our author (ariel@topspin.com) RDMA involves implementing a reliable transport protocol in hardware on the network interface card (NIC), and by supporting zero-copy networking with kernel bypass. Zero-copy network support enables the NIC to transfer data directly to or from application memory. This eliminates the need to copy data between application memory and the kernel. Kernel bypass enables applications to issue commands to the NIC without having to execute a kernel call. This reduces the number of context switches required while handling network traffic and ultimately let the devices or NICs handle increased speeds and bandwidth requirements.

A variety of vendors from Adaptec, Cisco and Intel to HP, IBM and Microsoft all support the RDMA effort. For more on this story see: https://www.nwfusion.com/tech/2003/0324techupdate.html