MPPs contain high performance proprietary interconnection networks that are much faster than the typical Ethernet local area network. The availability of such fast networks allows for the construction of workstation clusters that rival the performance of MPPs. ATM Concepts, Architectures, and Protocols. Ronald J. Vetter. ATM Concepts, Architectures, and Protocols.
Heterogeneity is also evident in the underlying network.
System failure is yet another consideration. If an application is using a large number of machines to execute for a long period of time, failures during program execution are likely. Processor heterogeneity complicates support for fault tolerance. ATM Concepts, architectures, and protocols. With traditional LANs such as 10 Mpbs Ethernet, the relative communication overhead is high and will even get worse as processors become faster.