Difference between Multicast Unicast --- and Supporting Cast

[magish01]

Could someone explain multicast and unicast, what it does, how to use it, and which is the best method to use when using E1.31.

Thanks

[john fulkerson]

^{I know you get more universes out of unicast somehow but couldn't tell you how lol}

[Ron Boyd]

My understanding is, and I could be wrong. Multicast sends all commands to all controllers. Unicast sends commands to a single controller with a specific IP address. This is why, in my understanding, how you can get more universes with Unicast. That's the short answer.

[bob]

I don't think multicast will enable you to support more universes.  Maybe there's some reason it would, and I'd be interested in hearing such a reason if so, but I'm unable to imagine one.

 

I think the main high-level functional difference, as relating to E1.31, is basically in ease of configuration.  Either could have advantages or disadvantages:

 

If you set up an E1.31 device to know that it's universe 37, then it will automatically know to listen to any commands that are broadcast on IP address 239.255.0.37 (which is a multicast address).  You don't have to tell it that IP address, or any IP address - it just figures it out automatically from the fact that it's universe 37.  You can then go into the LOR configuration and tell it universe 37 should use multicast.  Similarly, LOR then automatically figures out it should broadcast commands for universe 37 on IP address 239.255.0.37; you don't have to tell LOR that IP address, or any IP address.

 

On the other hand, if you want to use unicast, then you set up the E1.31 device to know that it's universe 37, and you also set up (or figure out) what the device's actual IP address is.  Let's say it happens to be 192.168.0.204.  Then you go into the LOR configuration, and tell it that universe 37 should use IP address 192.168.0.204.  So configuring it might be a bit more complicated than configuring multicast.

 

On the third hand, depending on how things like routers and switches in your home network are set up, it's possible that they'll disallow certain multicasts.  So if multicast E1.31 doesn't just work for you, and for some reason you don't want to use unicast, then you might have to poke around in the configuration of your network hardware, which isn't always entirely straightforward.

 

Another possible high-level functional difference (although I've never tried this myself): Any number of devices can be listening to a single multicast address (whereas there should be only a single device listening to any given unicast address).  So if you had two separate E1.31 devices, and for some reason you wanted the lights hooked up to each of them to act exactly the same as each other, I suppose you could set them both up to be universe 37, and then set up the LOR configuration to say that universe 37 should use multicast.

 

Oh, also: Again depending upon how your networks' switches and such are set up, multicast might cause more ethernet network traffic.  So maybe if you have a bunch of universes, and you've noticed network throughput degradation, you might want to try switching to unicast to see if that helps.

 

Aaaaaaand, now I see that people actually said unicast enables more universes. I misread as "multicast".  Unicast allowing more universes might be the case based on the last thing I said (network throughput).

[viennaxmas]

Multicast is a protocol which makes a lot of sense if the switch does support it. However Multicast support is only included in the more expensive units from HP / Cisco and others. In typical home switches, multicast is just blasted out through all the ports.

 

The idea behind it is that the switch actually handles distribution. If you take IPTV as an example - which can also work on MultiCast - the sending device would send one stream to a multicast enabled switch and the switch would then distribute the packets to the connected clients (let's say 24 clients are watching the same video feed). In this case, there would only be one stream to the switch and 24 leaving the switch. On unicast the sending device would have to serve 24 streams to the switch and from there 24 streams are bing sent to the playback devices.

 

Does it make a difference in what we do? Not really (aside from the added overhead in multicast). The stream leaving the computer does contain all universes on E1.31 if it is multicast or it would contain several streams with a subset of the universes. Aside from that, Bob has listed all teh advantages and disadvantages.

 

One important thing to keep in mind: If you have a managed switch at home and you use a dedicated VLAN for E1.31 - make sure to enable Multicast. Usually this kind of switch filters multicast since it causes a lot of unneccessary traffic in networks.

 

Configuration wise: Multicast is a bit easier to set up, as Bob mentioned you only need to assign the Universe number in the device, LOR does determine the Multicast IP by itself. On Unicast, you have to set it manually in LOR and set the universe in the controller.

 

Personaly I think unicast is the "cleaner" way of doing things ;-)

[magish01]

Thanks for all the input. I plan on making a 360 degree smart pixel tree with either 16 or 24 strands doubled up , and will probably use nutcracker to try and simulate the spiral weber tree with the pixel strands running straight up and down.

Edited June 28, 2013 by magish01

[Ron Boyd]

In reading this, does this mean I can run Unicast with LOR, or does it have to be Multicast. I seem to be trying to do both. I have a specific IP address for the E1.31 device and Multicast set up in LOR. Maybe that's why I can only get test patterns and nothing with a sequence. I guess I need to do some more research.

[viennaxmas]

Ron - it depends what device you are trying to control. J1sys ECG-P2 does understand both. Madrix only Multicast as in and out. LSP only produces MultiCast.

Multicast is usually easier to set up if your switch supports it and Multicast is supported by pretty much every E1.31 capable device.

[k6ccc]

The recent firmware for the SanDevices E682 and E6804 support multicast (as they always have) and now also unicast.  I have updated one of my E682s to the current firmware and configured it for unicast.  I will be switching all of my SanDevices boards to unicast before they are put into service.  I am not exactly running a normal home LAN, and I am using managed switches with a dedicated VLAN for my E1.31 operation.

 

One thing to keep in mind if you use a more normal home LAN and use WiFi.  If you are using multicast, all the E1.31 traffic will tie up your WiFi (especially if it's an older one).  When E1.31 first came out last year there were a number of complaints about that problem.  Using unicast will generally keep the E1.31 traffic off your WiFi.  If someone wants a detailed explanation, I can give it.

[Ron Boyd]

The recent firmware for the SanDevices E682 and E6804 support multicast (as they always have) and now also unicast.  I have updated one of my E682s to the current firmware and configured it for unicast.  I will be switching all of my SanDevices boards to unicast before they are put into service.  I am not exactly running a normal home LAN, and I am using managed switches with a dedicated VLAN for my E1.31 operation.

 

One thing to keep in mind if you use a more normal home LAN and use WiFi.  If you are using multicast, all the E1.31 traffic will tie up your WiFi (especially if it's an older one).  When E1.31 first came out last year there were a number of complaints about that problem.  Using unicast will generally keep the E1.31 traffic off your WiFi.  If someone wants a detailed explanation, I can give it.

OK Jim, Do you have a write-up on how to configure a 2, 682s and a 6804 on, a PC with a switch for Unicast. If LOR supports Unicast, how do I configure LOR for that. I already have all 3 set-up with a specific IP address and the latest firmware. I can get the test patterns to work just fine, but I can't get anything going to the Pixels while a sequence is running.

 

I'm going to try to set it back up today and work on configuring it again and a step by step in laymens terms would be great to have.

 

I'm nowhere a newbie with a PC, but I am a newbie at setting up network protocols and these Sandevices units.

 

Thanks for any help.

 

Ron

Edited June 29, 2013 by Ron Boyd

[k6ccc]

Yea Ron, it's easy.  I will type it up and do some screen shots this evening.

[k6ccc]

OK here goes some instructions.  First to configure the E682 or E6804 for unicast.  First, you must be running at least version 4 firmware.  Second, under receive mode, select unicast E1.31 instead of multicast E1.31.  That's it for the E682.

 

Now for the DMX setup in LOR Network preferences.  Select the desired DMX Universe on the Network Preferences screen (shown with the unicast already set).

 

On the settings for the selected DMX universe, select "Use E1.31", and then select "Specify" and enter the IP address of the desired E682.

 

 

If you are going to have more than one E1.31 board, I would suggest keeping DMX universes separated logically.  For example, the board I am showing is used for my pixel tree and it is allocated DMX universes 11-20 (although only using 11-16 at this time).  The E682 that will be used for year round landscape lighting will be allocated DMX universes 1-8 (although it will only use 2 universes normally), and the E6804 which will also be used for year round landscape lighting is allocated DMX universe 9 (it's only going to have 17 RGB pixels on it).

 

Hope that helped.

[Ron Boyd]

So, In the DMX set-up, if a Universe is not used, you just leave those at the default LOR settings, ie: "Adapter Address = None". Is this correct?

That's pretty much how I have it set, except I went ahead and assigned the un-used Universes to the devices.

 

Last week when I hooked 1 of them up, I got test patterns all working as expected, but no lights during a sequence.

 

Thanks for the write up Jim. I didn't mean for you to do this last night so late, but thanks anyway. I really do appreciate it as I'm sure everyone else will too.

 

Ron

[k6ccc]

Correct, unused DMX universes should be left unassigned.

 

As for no lights from a sequence, make sure that the comm listener is open (should open up with the control panel is started), and that control lights is checked.

 

BTW, no problem on doing the writeup late last night.  I tend to be a night owl on the weekends.

[bob]

In reading this, does this mean I can run Unicast with LOR, or does it have to be Multicast. I seem to be trying to do both.

 

This might have already been answered by others, but just in case: LOR supports both unicast and multicast E1.31.

[Ron Boyd]

Thanks Bob. That was what I was needing to know. Maybe if I get the settings for Unicast only and not both, I might get this thing up and running this weekend.

[k6ccc]

I have used both Unicast and multicast (although not at the same time).  I see no reason that it would not work with one or more universes on unicast and others on multicast.

[Frybread]

Thanks folks good info but I want to make sure that I get this correct.

 

I have 1 e682 and I want to control 8 strings of 100 ws2811 with it.  I want this to be only on 8 of the ports on the E682 and on 8 universes. 

Do I need to 

1) update the firmware to version 4

2) run the system in Unicast.?

 

Thank You

[k6ccc]

If you insist on using 8 universes, yes you would have to use Unicast and version 4 firmware.  However there is no need to run each string as it's own universe.  If you are running 800 pixels or 2400 channels, that is a little under 5 universes - which would not require unicast on your E682.

[Frybread]

7f I have 100 pixel strings how do I configure the E682?