1. Myrinet 2Gbps Networks (http://www.myri.com)

2. Overview
Myrinet is a high-performance, packet-communication and switching technology that can be used to interconnect clusters of workstations, PCs, servers, or single-board computers.
Cluster computing has the following advantages:
high performance
high availability
Cluster computing needs:
High throughput bulk data transfer
Low latency message passing

3. Pictures of Myrinet

4. Myrinet’s Features
Full-duplex 2+2 Gigabit/second links, switch ports, and interface ports
Flow control, error control, and "heartbeat" continuity monitoring on every link
Low-latency, cut-through, crossbar switches, with monitoring capability
Switch networks that can scale to tens of thousands of hosts
Host interfaces that execute a control program to interact directly with host processes ("OS bypass") for low-latency communication, and directly with the network to send, receive, and buffer packets

5. A Possible Configuration
Two computers can also be
connected directly through
a cable.

6. Packet Format and Routing
Source routing
An IP packet can be carried by a Myrinet packet as its payload.

7. Deadlocks May Form Source routing is used.
A network mapping program needs to be run on one host to discover the map of the network. It then distributes the map to all other host interfaces.)
Cut-through switching is used to reduce message latency. (wormhole routing)
For high-performance distributed application programs, latency will be more important than throughput (because latency cannot be improved whereas throughput can be improved.)
Thus deadlock situations may form.
Myrinet thus provides a monitoring and timeout mechanism to break deadlock situations.

8. Myrinet Host Interface
1995 version
We can write the firmware source code, compile it, download it, and run it on the host interface!!!!

9. Myrinet Host Software
Myrient can use zero-copy and checksum offload capabilities to improve transfer throughput.