[whatwg] RWD Heaven: if browsers reported device capabilities in a request header (Boris Zbarsky)

Ryosuke Niwa rniwa at webkit.org
Mon Feb 6 14:49:14 PST 2012

2012/2/6 Kornel Lesiński <kornel at geekhood.net>

> On Mon, 06 Feb 2012 20:00:45 -0000, Irakli Nadareishvili <irakli at gmail.com>
> wrote:
>  1. Adaptive images:
>> To optimize user-experience on smart-phones (most of which have
>> relatively small screens, and are on slow connections most of the time)
> Be careful with generalizations like that.
> Mobile devices can be connected to high-speed networks. Laptops can be
> tethered via mobile networks.

Right.  When I had a smart phone, it was on WiFi 90%+ of the time because
I'm either at work or at home although I browsed on the phone when I was on
move disproportionally more than I was at work or home.

I appreciate optimisations you're trying to make, but simply reporting
> basic capabilities in an HTTP header isn't going to work well in other than
> few most common cases.
> I hope we could come up with a better solution that can all the
> optimisations and improved experience you want to achieve, but doesn't have
> pitfalls of assuming that slow networks and touch screens go hand-in-hand,
> or that devices with keyboards also have mouse and < 100dpi screen, etc.

I'm totally with you. While I do sympathize with the view that we need some
ways to let servers figure out which resource to be sent and how it should
be sent, I don't think web developers should be making such decisions
solely based on the types of devices they're serving.

On Mon, Feb 6, 2012 at 2:30 PM, Boris Zbarsky <bzbarsky at mit.edu> wrote:
> And even if you are on the move, EVDO rev B is in the 5-15 Mbit/s range,
> and HSPA+ services that deliver 28 Mbit/s are on the market right now, with
> theoretical peak bandwidth for the standard closer to either 84 Mbit/s or
> 168Mbit/s depending on the hardware configuration.
> A real problem with network performance on many cell networks is not the
> bandwidth, which is at least comparable to basic DSL, but latency.  Of
> course for latency issues image size is a smaller problem, and desktops on
> sattelite connections have latency issues of their own....

On the other hand, mobile networks tend to have a huge variance on the
packet loss rate (sometimes 100% if the user is moving into an elevator)
and websites need to behave differently, e.g. cache more images on Map app.

On that note, it might be more useful to add a header indicating that
they're on slow network, mobile network, and such although it might be
better for servers to auto-detect latency and bandwidth for that kind of
use cases.

- Ryosuke

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