[mythtv-users] myth on separate subnet

Ben Kamen bkamen at benjammin.net
Thu Jan 14 17:54:55 UTC 2010


On 1/14/2010 11:33 AM, Jay Foster wrote:
>
> I built my first MythTV system 1 year ago (combined FE/BE) and did
> the same thing. The MB has 2 GB ethernet interfaces, both of which
> are statically configured. The first interface connects to my in home
> network/router/DSL. The second is connected to a GB switch with 2 HD
> Home Runs attached (I may add a third). The BE runs a DHCP server on the
> second interface to provide IP addresses for the HD Home Runs. This
> works great. When I designed this FE/BE, I was concerned about running
> out of network bandwidth recording 4 (future 6) HD programs at once, so
> opted for a dedicated private network for the HD Home Runs (my in home
> network is 10/100 only).
>
> The only down side is the HD Home Runs are not accessible from any other
> machine in my home (none of my other machines are powerful enough to use
> them anyway).

In a layer 2 switched network you havent' gained anything except isolating your tuners from the rest of the network.

Switching is layer 2 routing. After a while when layer 2 switches came out, you started to hear a lot of
marketspeak of layer3 switches. (Cisco had a lot of products declared this way). And it's ok.. because they are
the same thing in basic concept.

You have a packet. It has a source and destination.
The switch (router) then makes an intelligent decision where to send that packet (port based table MAC lookup) and then
sends it there. If you have a 24 port layer 2 switch, then 2 ports can have a conversation while the other 22 see nothing.

In your case of taking it up a notch to layer 3 with static IP's, it doesn't matter because ARP figures out the MAC address on that NIC and sends the traffic there anyway.

You could always change back to flat and keep all the benefits with none of the isolation effects you have now.

  -Ben


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