Cheap Gigabit switch will allow DHCP thru it?

[Ben Scott]

On Dec 29, 2007 12:31 PM, Bruce Labitt <bruce.labitt at verizon.net> wrote:
> I'm looking to add another hdhomerun tunerbox to my myth setup.  I have
> a DHCP server running to give the existing tuner its IP address.  Can I
> add a cheap gigabit switch to add the other tuner?
> Will the requests for IP address be routed to the server properly?

  Short answer: Buy the switch and it will likely just work.  If it
doesn't just work, it will be a simple matter to make it just work --
just ask here.

  Longer answer:

  A switch is what is called a "layer 2" device; all it does is
forward Ethernet frames.  IP, DHCP, and friends are all "layer 3" or
higher.  So DHCP and everything else will not even be aware that the
switch is there.  It's all one, big happy Ethernet network.

  That means that the DHCP server, and your HDHRs, will all appear to
be peers to each other.  So DHCP will flow just fine, but there will
also be no way for any of the devices to tell how they are physically
connected (i.e., they don't know there is a switch involved, or what
port of the switch they are plugged into).

  All that said, every Ethernet device has an address (sometimes
called a "MAC address") which uniquely identifies the device.  So each
HDHR has a unique Ethernet address.  The DHCP server will be aware of
that address, and can potentially use it to assign a specific IP
address to each one.

  What the right thing to do is depends on how MythTV finds the HDHRs.
 I seem to recall that MythTV uses a broadcast packet to find the
HDHRs.  If that is the case, the IP address of the HDHR won't matter
-- the broadcast packet will reach both of them, and MythTV will have
to tell them apart.

-- Ben