For reasons of economy, Roberts decided that no direct link was needed between UCLA and Utah, or between Santa Barbara and Utah, so that all traffic destined for Utah had to go through the IMP at SRI. That was fine as long as it was up and running. If it crashed, the network would divide and Utah would be cut off until SRI was brought back on-line. As it would turn out, the four-node network that Roberts designed was not a robust web of redundant connections.
