[e2e] Network level qos support for web services

[Christian Huitema]

> Are there (applications using, requirements for, ...) web services out
> there which really DO require network QoS (i.e. have strict delay
bounds,
> require throughput guarantees... something like this)?

In practice, there are three kinds of networks: those that have enough
capacity for the desired application, those that don't, and those that
are in between. QOS schemes are only useful in the latter case, when the
network almost has enough capacity for the application's demand, but not
quite. They are useless if the network is to narrow: no amount of QOS
will enable HDTV on a narrowband modem line. They are also useless if
the network has enough capacity, since they only serve there to make the
network more complex.

QOS is not the only possible response in the "in between" state. If the
network has "almost enough capacity", one can generally redesign the
application to consume slightly less resource, e.g. use more
compression. If the application is valuable, there will be incentives to
increase the network capacity so it will always work.

The "in between" case is a transient state, and the domain of
applicability of QOS solutions is very narrow.

-- Christian Huitema