The MEMORY CHANNEL network is a dedicated cluster interconnect that provides virtual shared memory among nodes by means of internodal address space mapping. The interconnect implements direct user-level messaging and guarantees strict message ordering under all conditions, including transmission errors. These characteristics allow industry-standard communication interfaces and parallel programming paradigms to achieve much higher efficiency than on conventional networks. This paper presents an overview of the MEMORY CHANNEL network architecture and describes DIGITAL‘s crossbarbased implementation of the second-generation MEMORY CHANNEL network, MEMORY CHANNEL 2. This network provides bisection bandwidths of 1,000 to 2,000 megabytes per second and a sustained process-to-process bandwidth of 88 megabytes per second. One-way, processto-process message latency is less than 2.2 microseconds.