As I think we're virtually all in agreement that E1.31 is a mandate for large channel counts. So USB RS485 controllers are basically out of the picture. So how should we setup a network in order to run E1.31 without loosing any packets or having stability issues. Well, I thought I'd through my $0.02 in on how I think the network should be setup.
First, keep your home and show networks independent of each other. That doesn't mean that you can't pass data between them just make sure if you do there is a router or at least a level 3 switch between them. You don't want your home data interfering with your show network.
My recommendation is to have two network cards on your show computer. One tied to you home network and the other your show network. The one to your home network can be either WiFi or physical ethernet but the show network should be physical ethernet connection, only NO WiFi, and the show computer connection should be Gigabit Ethernet. Also, there is no reason to try and save a few $s on old 100Mbs switches. Get the latest as it should last you a few years. As I said don't use WiFi unless you absolutely have to due to interference from other networks. Stay with ethernet even if you have to run it a couple hundred feet as you'll be happier in the long run.
The Light Show network. A lot has been said about using unicast or multicast transmissions to the E1.31 controllers. In the past the only sensible solution was to use unicast as few if any low cost switches were available for under $600 to $1,000 that could handle IGMP snooping required to do multicast without any problems. Without IGMP snooping if you send multicast packets to the switch it will send those packets to EVERY E1.31 controller on your network which causes several problems. First, since almost every E1.31 controller we'll be using is only 100Mbs if your sending from your nice 1Gbs network off your show computer your going to totally overrun your 100Mbs connections to those E1.31 controllers. Can you say "Switch Kill"? Second, the E1.31 controllers had to sort out their packets from those going to the other E1.31 controllers which can overload the processor in the E1.31 controller which then causes unexplained errors with your display. This issue has already been reported on DIYC.
But that was then and this is now. Now Netgear's has their ProSafe Plus GS1xxE line of switches it's no longer a problem. These switches come with full IGMP snooping as well as several higher end features, such as VLANs, at a price that consumer are willing to pay.
Here is a list of the switches we should be able to use along with the current pricing from NewEgg. Other outlets might have a better price I'm just using them as an example.
Which switch should you get? Well if you really think you won't have more than 4 E1.31 controllers I'd start wit the 8 post since it's only a few $'s more than the 5 port. The 8 port would give you 7 E1.31 controllers which should be enough for all but the largest shows.
Hope this helps and happy blinking lights to all.