User guide
5
Designing the network layout
Selecting the right kind of switches is the rst stage; ensuring they are laid out
correctly is the next.
General recommendaons
• The general rule is: Keep it at. This means adopting a basic line cascade
structure with a at structure rather than a pyramid or tree arrangement.
• Keep the distances between the switches as short as possible.
• Ensure sufcient bandwidth between switches to eliminate bottlenecks.
• Where the AIM box is used to administer multiple ALIF transceivers, you must
ensure that the AIM box and all the ALIF units under its control are located
within the same subnet.
• Avoid using VGA-to-DVI converters, where possible, instead replace VGA video
cards in older systems with suitable DVI replacements. This is because VGA-
to-DVI converters create sufcient background noise (even in static images)
that an ALIF transmitter would be forced to send all of every video frame, thus
creating large amounts of unnecessary network trafc.
• Where a sizeable number of ALIF units (e.g. ten or more) will be used on a
subnet, create a private network, i.e. no competing trafc from other network
devices.
Layouts
The main problem with a pyramid or tree layout is that essential IGMP trafc
issued by the Querier device (Layer 3 switch) at the top of the pyramid will
only travel down each leg of the pyramid. What this means is that an AdderLink
Innity unit located in one leg cannot communicate with an AdderLink Innity unit
situated in another leg.
Layer 2 Switch Layer 2 Switch Layer 2 Switch
ALIF RX ALIF RX ALIF TXALIF TX ALIF RX ALIF RX
Layer 3
Switch
(Querier)
continued