nicholas.hatch at gmail.com
Wed May 11 19:25:56 UTC 2011
On Wed, May 11, 2011 at 11:39 AM, George Bonser <gbonser at seven.com> wrote:
> There are other things to take into account. If you
> increase the time it takes a mobile device to complete a transaction by
> only a couple of seconds, if you multiply those couple of seconds by
> all of the users in a large metro area, you end up with devices
> increased use of network resources (and increased battery drain on the
> devices themselves). Anything that can be done to speed transactions up
> and get those transmitters shut off as quickly as possible is a win.
I agree that seconds sometimes matters, but the latency of a transaction
doesn't have a linear relationship with radio or battery usage on a mobile
device. Because of the timers involved in the state transitions (eg
CELL_FACH -> CELL_DCH), a few seconds of extra latency often is
inconsequential because there is a minimum duration for which the radio will
stay awake anyways. Coalescing techniques like Android's setInexactRepeating
method of the Alarm Manager also optimize radio access across multiple apps.
And if I'm not mistaken, it's the transition to/from CELL_DCH which is the
most expensive resource-wise for network operators, not the duration of
keeping this state.
The argument that IPv6-induced latency is going to affect mobile devices
disproportionally doesn't seem especially compelling.
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