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High speed at reasonable costs are the end-goal. However, it is important to be able to plan for when one will need such links, to know what one will be able to achieve, and for regular users to be ready to use them when the commonly available. This takes some effort up front to achieve and demonstrate.

True, however as it was mentioned before, why not do the same type of testing in a lab environment between a couple >of boxes having the TCP stack insert appropriate delays? When in 1995 we were getting simplex IP links over satellites up that is how we did the testing before bringing them up on the birds.

Following up on and driven by the work leading up to and following the Land Speed Record, some of the Caltech people collaborating on this record together with collaborators from SLAC and elsewhere, are proposing a "WAN in the Lab" that can be used for just such testing. This saves on leasing fibers but there are still considerable expenses to run at 10Gbit/s rates (cpus, NICs, optical multiplexing equipment etc.). It is also a much more controlled environment that simplifies things. On the other hand it misses out on the real world experience, and so eventually has to be tested first on real world lightly used testbeds, and then on advanced research networks and finally on production networks, to understand how issues such as fairness, congestion avoidance, robustness to poor implemementations or configurations etc. really work.