[e2e] Question the other way round:

Sergey Gorinsky sergey.gorinsky at imdea.org
Wed Nov 20 06:21:58 PST 2013

  Dear Detlef,

  If a sender chooses the D class for all its flows, each of its flows is
served with small queuing delay at the bottleneck link (but with a smaller
forwarding rate than the rate given to a throughput-greedy flow of another
sender that chooses the R class).

  The RD design is work-conserving and does not cause underutilization.
The partition of the bottleneck-link capacity between the two classes is
dynamic and depends on the numbers of R and D flows.

  Trying to fit this into your metro-carriage analogy, one can think of
the D class as quiet (low-delay) carriages and the R class as noisier
(higher-throughput) carriages. The point is that some apps naturally
prefer noisier carriages, i.e., a higher forwarding rate regardless of
queuing delay. Charging differently for the R and D services would only
distort the natural preferences of the customers. Thus, the RD service
differentiation is not an issue of goodness vs. badness (or wealth vs.
poverty) - it is just that some customers prefer noise and the others like

  Best regards,


On 11/19/13 12:05 PM, "Detlef Bosau" <detlef.bosau at web.de> wrote:

>> Sergey,
>> what happen in your approach, when a sender chooses class "D" for all
>> pakets and flows?
>Don't you achieve QoS by underutilization in your approach?
>So, while with metro pricing you make the crowds stay away from the
>upper class carriage by the ticket price - while in your approach
>the sender has to care for a quiet carriage by appropriate pre selection
>- hence, the tickets can be offered for the same price?
>So, the selection is the same, only the bad guy who does the selection
>changed the location?
>Detlef Bosau
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