Here’s another new twist on converged networking: the InfiniBand Trade Association (IBTA) has released a new specification for building Remote Direct Memory Access (RDMA) into 10-Gigabit Data Center Ethernet (DCE) networks.
InfiniBand providers claim their value proposition is the same as Fibre Channel over Ethernet (FCoE) — the ability to combine multiple types of network traffic over one wide pipe. But according to Brian Sparks, senior director of marketing communications at Mellanox and co-chair of the IBTA’s Marketing Working Group, RDMA over Converged Ethernet (RoCE, pronounced “Rocky”) can theoretically be run over DCE alongside Fibre Channel traffic. “With priority flow control in DCE, you can do both, but it’s up to the NIC provider,” Sparks said.
Sparks said Mellanox is planning to release products that support RoCE, and that other members of the IBTA manufacturers including Broadcom, Intel and Chelsio, may be working on 10-gigE NICs that support RoCE as well. The IBTA envisions RoCE finding use cases in financial services companies or businesses with a similar reliance on databases and low tolerance for latency.
IBTA is also hoping this spec will fare better than its last attempt to drive RDMA into the Ethernet world, a spec for RDMA over 1 Gigabit Ethernet iSCSI links called iSER, known in its Intel incarnation as iWARP. “It’s had a hard time getting market adoption, since the adapters are a little high on the power side,” Sparks said. “They require a slightly more expensive NIC and maybe only get a microsecond or two latency benefit.”
RoCE will be different, Sparks said, because latency is much improved over 10-Gig networks, and DCE will do away with the need to offload TCP/IP traffic, one of the hindrances to better performance with iWARP.