The Memory-Integrated Network Interface

• Authors: Ron Minnich;Dan Burns;Frank Hady
• Venue: IEEE Micro
• Year: 1995

We are designing a zero-copy ATM interface call MInetwork interface, the Memory Integrated Network interface. MInetwork interface has a target bandwidth of 1 Gbps and will support application-to-application latency of 1.2 microseconds. MInetwork interface is a multiuser ATM interface which resides in the memory space of the computer system, as opposed to I/O space. Applications will have direct access to pages of memory which are used for the network I/O; thus applications can send and receive packets with no operating system support needed. An application can initiate packet transmission with one memory write; it can determine if a packet has arrived by checking a per-circuit control and status word. At the same time, the operating system can use MInetwork interface for its own communications and for supporting standard networking software such as TCP/IP and NFS. Initial structural VHDL simulations have shown that for single ATM cells we can "bounce" an ATM cell from application to application in a round-trip time of 3.9 microseconds (including software overhead on the relaying node), at a bandwidth of 10 Mbytes/s. For 960-byte packets, the bandwidth is 103 Mbytes/s. The architecture of MInetwork interface is motivated by our experiences with applicatio ns we have run in cluster and distributed computing environments. We have used from 48 to 200 computers per application, and have observed that successful applications are ones that use the network very little. The MInetwork interface design is targeted at the kinds of applications we cannot currently run, those that need to send or receive data at very frequent intervals.