Bandwidth

Bandwidth should be matched to expected load as closely as possible. If the intended message-passing applications have only modest communication requirements and no significant parallel I/O requirements, then a fast, expensive interconnect may be unnecessary. On the other hand, many parallel applications can often benefit from large pipes (high-bandwidth interconnects). Clusters that are likely to handle such applications should use interconnects with sufficient bandwidth to avoid communication bottlenecks. Significant use of parallel I/O would also increase the importance of having a high-bandwidth interconnect.

It is also a good practice to use a high-bandwidth network to connect large nodes (nodes with many CPUs) so that communication capabilities are in balance with computational capabilities.

An example of a low-bandwidth interconnect is the 10 Mbit/s Ethernet. Examples of higher-bandwidth interconnects include SCI, ATM, and switched FastEthernet.