[mythtv-users] Way out idea on watching same thinginmultiplerooms

Gareth Glaccum gareth.glaccum at btopenworld.com
Thu Jan 7 04:03:20 UTC 2010


----- Original Message ----- 
From: "Eric Sharkey" <eric at lisaneric.org>
To: "Discussion about mythtv" <mythtv-users at mythtv.org>
Sent: Wednesday, January 06, 2010 10:13 PM
Subject: Re: [mythtv-users] Way out idea on watching same 
thinginmultiplerooms


On Wed, Jan 6, 2010 at 5:07 PM, Gareth Glaccum
<gareth.glaccum at btopenworld.com> wrote:
> The problem is, that as standard, most switches do not decode/ perform
> multicast snooping. This means that they do not listen for multicast joins
> and leaves, and instead broadcast multicast communications to all ports.
> This is a major waste of bandwidth.

That doesn't sound so bad to me.  Certainly not for the use case being
discussed here.  Most of that "wasted" bandwidth wasn't going to be
used anyway.  The alternative of using unicast sounds much worse.

But in the case where I have a TV plugged into a GB network, and the TV only 
has a 10Mb/s interface implemented, it means that it is getting a broadcast 
stream of an HD channel that it doesn't need. Its switch on the port starts 
to drop packets because the TV cannot receive data fast enough (10Mb/s ports 
being half duplex as well). This means then that the TV can no longer 
receive perfectly all the data that it was expecting. My TV is only 1 year 
old, I have no wish to upgrade it just because the network port stops 
working because a program is flooding its network port.
This is an edge case example, but a problem none-the-less. 



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