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Re: 2.0 and Radio Impacts/battery efficiency

From: Roberto Peon <grmocg@gmail.com>
Date: Fri, 13 Apr 2012 00:27:21 -0700
Message-ID: <CAP+FsNcGfj_G1U9nWA5qj+tW8rWwMn0+HVhYA40XXQg_hWfTuA@mail.gmail.com>
To: Zhong Yu <zhong.j.yu@gmail.com>
Cc: Salvatore Loreto <salvatore.loreto@ericsson.com>, HTTP Working Group <ietf-http-wg@w3.org>
The most obvious reason would be that the server sends a packet which
requires the radio to awaken (e.g. because the tcp stack emits a packet
back).
-=R

On Thu, Apr 12, 2012 at 8:23 AM, Zhong Yu <zhong.j.yu@gmail.com> wrote:

> I don't get it. Cerntainly a new connection requires an extra round
> trip which drains extra power, but only for the duration of the round
> trip. Why is it "extremely expensive"?
>
> The article says
>
>    "Every time you create a new network connection, the radio
> transitions to the full power state."
>
> which I don't think implies that,
>
>    "If you reuse a network connection, the radio does NOT necessarily
> transition to the full power state."
>
> To compress all network activities(including FIN-FIN) into a shorter
> time span, the article event suggests that
>
>    "so it's also good practice to close your connections when they
> aren't in use"
>
>
> On Thu, Apr 12, 2012 at 3:52 AM, Salvatore Loreto
> <salvatore.loreto@ericsson.com> wrote:
> > Hi there,
> >
> > here a good read about "Optimizing Downloads for Efficient Network
> Access"
> >
> http://developer.android.com/training/efficient-downloads/efficient-network-access.html
> >
> > the major points are
> >
> > 1) reducing the number of connections is a MUST as each new network
> > connection is extremely expensive
> > from a Radio/Battery prospective
> >
> > It is also worth to add that the server-initiated closing of  idle
> > connection is also something to avoid.
> > So if the client keeps the connection open longer, then the specification
> > has to mandate servers to keep
> > the connection open for very long.
> >
> >
> > 2) the ping frequency is also very important:
> > "An app that pings the server every 20 seconds, just to acknowledge that
> the
> > app is running and visible to the user, will keep the radio powered on
> > indefinitely"
> >
> >
> > 3) also Prefetching data need some consideration from the radio
> prospective
> > as Prefetching data (on a wireless connection)
> >  may cost money but for sure has a cost from a battery prospective
> >
> >
> > cheers
> > Sal
> >
> > --
> > Salvatore Loreto, PhD
> > www.sloreto.com
>
>
Received on Friday, 13 April 2012 07:27:50 GMT

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