Instruction manual

C-Bus By Demand 3
Training Manual 14
1.7 Command Routing
When using an Ethernet backbone in a multiple network C‐Bus installation, it is important to
understandthatCNI’sdo not support tunnelling. Tunnelling is when a command is sent from
oneCNItoanother,throughtheEthernetnetwork.
Thismeansthatifaninstallationused5CNI’s(oneoneachfloor),therewouldbenodirectway
toroutemessagesbetweennetworks.However,interconnectivitycanbeprovidedby:
 • running a network bridge between the networks (remembering the li
mitations of the
networkbridge).
 • mappinggroupaddressesvialogicinSchedulePlus.
Iftheinstallationrequiresnetworkinterconnectivitythenusi
ngaCNIbackbonemaynot
bethemostappropriatenetworktopology.

1.8 Network Extending
Times may occurwhenanetworkusing
 a CNIreaches thelimit of oneoftheC‐Busoperating
parameters.Ifthisoccurs,anetworkbridgecanbeusedtoextendthenetworkjustasthoughaif
aPCIn
terfaceisused(seeFigure8).

Figure 4: Extending a network with a CNI.
ThisisexactlythesameasnetworkextendingforaPCInterface.

1.9 C-Bus Network Interface Location
WheninstallingaCNIintoacommercialinstallation,commonpracticeistoinstallthemneara
distributionboardonthenetworkitiscontrollin g. 
Under no circumstances should  a CNI be installed into a distribution board. Wiring
regulationsspecifythatEthernetsh
ouldneverbewiredintoanenclosurewithmains.
Ifitispossible(dependingontheinstallation)installallCNI’sintoacentrallocation,thiscould
be in the basement of a building or a riser. Having all or multiple CNI’
s in one location will
allowtheinstallationtobeeasilyupgradedinthefuture,aswellassimplifyingthemaintenance
ofthenetworks.
This location may not suit every application, and is purely a suggestion to future proof
the
installation.