[mythtv-users] Back of the envelope calcs for minimum network speed

[Robert Denier]

I suspect that if it isn't too hard to do a gigabit switch and adapters
combined with cat 5e/6 will give you a more responsive system,
especially when you jump around in the video, but the numbers below make
it look like the wireless would work...

On Mon, 2005-09-05 at 22:32 -0700, Fedor Pikus wrote:
> On 9/5/05, Brian McEntire <brian.mcentire at gmail.com> wrote:
>         Hi -
>         A question about network capacity:
>         
>         I'm planning to put a front end by the TV, and a back end in a
>         different part of the house. The primary purpose for this
>         MythTV setup is HDTV viewing.
>         
>         Some early HDTV recordings are about 2.4 GB for 30 minutes.
>         
>         This works out to 2.4 * 10^9 * 8 bits/B / 30 min / 60 sec/min=
>         10.7 Mbps
> 
> About 1.37 MB/sec. You can get this from 802.11g, but it's right at
> the limit of the standard 54 MBps (and only if you don't use the
> network in mixed mode, if you add 802.11b clients the throughput will
> drop). However, this is well within the limits for the "fast" 11g,
> i.e. proprietary extensions which typically double the speed of the
> network (you've probably seen 108 Mbps devices advertised, that's
> them). The catch is, they are usually 108 Mbps to each other, and 54
> Mbps to another brand, if you're lucky. 
> 
> I have a network of several Viewsonic WAP/Bridge devices (WAPBR-100,
> CompUsa sells them on-line if you can't find them) and I get 2.4
> MB/sec transfer rate to and from my Myth box. These are ethernet to
> wireless bridges, not wireless adapters, which is the best since you
> don't have to mess with wireless drivers - you just take all your
> bridges to one place, connect them to a PC one by one, configure them
> all, one as a WAP and the rest as bridges, and then connect them to
> any ethernet-enabled device, and with no changes to the device you're
> now connected to wireless.
> 
> Fedor
> 
> 
>         For streaming from the backend to the frontend (aka accessing
>         via NFS?) it appears it will exceed Ethernet speed and require
>         fast ethernet. I don't have cable run, so my question is, for
>         a strong signal, is it reasonable to expect a quality stream
>         over 54 Mbps wireless-g or is running CAT5/6 a better bet?
>         
>         Thanks!
>         
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>         
> 
> 
> 
> -- 
> Fedor G Pikus (fpikus at gmail.com)
> http://www.pikus.net
> http://wild-light.com 
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