1. New to Christmas lighting? Get started with the AusChristmasLighting 101 Manual:
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101 gibberish

Discussion in 'Provide Feedback: 101 Manual' started by AAH, Mar 12, 2018.

  1. AAH

    AAH I love blinky lights :) Community Project Designer Generous Elf

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    Ryan and I are getting close to having the ACL 101 completed and I'm going away for a few days and leaving him unsupervised. This morning I typed up a fairly incoherent page of info that I'd like to get some of into the 101.
    Comments or feedback on the benefits/non benefits/issues/accuracy of what I've typed up would be appreciated. The manual has grown somewhat in size than it used to be and this is among the last major bit of info that may go in.
    Some of the E1.31 unicast/multicast may get referred to the wiki

    Alan

    E1.31
    E1.31 devices need to have an IP address in order for data to be routed to the correct place. The IP address can either be static which means that it is user assigned or it is dynamic and it is assigned via a DHCP server. The DHCP server is typically in the form of a router.

    Unicast data is data that will only follow a path from the sequencer or sequence playback device to the assigned IP address and only transporting Universes and data that are defined.

    Multicast data is data that is sent out from the sequencer or sequence playback device with Universe data but no assigned destination IP. The router or switch will accept the incoming data and alternately send it to all connected E1.31 devices or in the case of IGMP snooping routers it will learn what devices want what and will only send the required universe data to that device/s.

    Benefits of Unicast data
    Only the E1.31 device at the destination IP will receive the data that the sequencer or sequence playback device is sending those packets to.

    Benefits of Multicast data
    There is no need to know the IP address of destination E1.31 devices.
    It is possible to have the same universe going to multiple E1.31 devices if only part of a universe is used on 1 device and the balance is used on another 1. It can also be useful if part of a display is mirrored.

    Pitfalls to Unicast data
    The biggest pitfall to unicast data is that if there is data being sent out to an E1.31 device on an assigned IP and it isn’t connected, powered up or on that IP address then the sequencer or sequence playback device will typically bog down as it continuously tries sending and re-sending out data packets looking for the destination but unable to find it. It can also flood the router.
    The second pitfall is that if the device IP isn’t what is expected or it gets changed then the data won’t get to that device.

    Pitfalls to Multicast data
    If using multicast without a router that has IGMP snooping then every E1.31 devices gets sent every data packet. If using a device that doesn’t have a lot of processing power like a diy Arduino or similar then it can cause them to get bogged down. They have to process every incoming data packet, analyse them to see if they are required and then reject unwanted ones.

    E1.31 IP addresses
    In order to connect to an IP advice it has to have an IP. In order to be connectable the computer and E1.31 must have compatible IP ranges as must the router.

    The 2 settings most commonly associated with E1..31 configurations are the IP and the Network Mask (or netmask).

    The IP is a 32 bit number arranged as 4 8 bit numbers. Each of these 8 bit numbers is known as an octet. Common IP ranges that are used are 10.*.*.* and 192.168.*.* with 172.16.*.* sometimes used. Every computer and device on the network must have its own exclusive IP address. They should all be in the same IP range. ie have the same 1st and possibly 2nd and 3rd octet.

    The network mask (netmask) limits the range of IP’s that are accessible from device to device. A Netmask of 255.255.255.0 which is quite common would allow devices 10.0.0.1 through to 10.0.0.255 to communicate with each other but prevent 10.0.0.1 communicating with 10.0.10.1 or 10.10.0.1. A netmask octet of 255 means that the matching IP octet on 2 devices must be an exact match. A netmask octet of 0 allows the full 0-255 range of IP octets to communicate. It is possible to use other than 0 or 255 but generally for home lighting control these 2 values are all that is required.

    Pixels
    When working with pixels it is necessary to ensure the exact number of pixels is assigned in the sequencer and pixel controller. Because pixels have no addressing then if there is a miscount between what is actually on the display and what the sequencer has then there can be a lot of confusion generated especially if there is more than 1 prop on a given output of a pixel controller. Xlights and potentially other sequencers have the ability to test individual models as part of the test feature. It is always worthwhile using this feature, if available, to check that all of a model turns on as it should and also that no other model turns on.

    Generally speaking it is possible to assign virtually any universe and channels to any output on a pixel controller. There will be practical limitations as to the number of pixels per output (typically under 1020) and they are normally limited to contiguous universe numbers. Output 1 may use Universe 1 Channel 1 through to Universe 4 Channel 10 for a mega tree or instance. It is possible to use the balance of Universe 4 on output 2 if required or alternately another Universe could be assigned on the pixel controller for output 2.

    As far as data goes it is better to fill universes as close to 512 channels as is feasible. The full 512 channels of a universe is typically sent to the E1.31 devices so having universes with only a small number of channels used means that there is a lot more data being sent out unnecessarily. Usually it would be normal to ensure that universes aren’t spanned across different E1.31 devices although this can be handled with multicast.
     
  2. keithsw1111

    keithsw1111 Full Time Elf

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    The pitfalls of unicast data is true on the pi but not on PCs or macs.
     
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  3. OzAz

    OzAz Senior Elf Generous Elf

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    Will there be more explanation of the 512 channels per universe limit and how if you have 171 pixels the 3rd colour of the last pixel will be on the first channel of the next universe. Which is why some prefer 510 as (arbitrary) max limit per universe; because a) it helps reduce confusion in planning outputs, b) some controllers may have issues (falcons don't of course :) ).
    I've seen this question many times since I started in this hobby, including from myself :laugh:
    Also will there be a full explanation of how pixels, universes and channels work, ie the math behind it? I've used the picture from the holidaycoro site a few times to help myself and others understand this. Obviously you can't use that one, but perhaps someone can draw up a generic version?
    See this thread where I used it to explain such information.
     
  4. AntinOz

    AntinOz New Elf

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    Some other comments:

    Unicast - more resources required on the sender as it has to send a packet to every receiver vs multicast where it only sends one packet
    Netmasks - with the mask you highlighted (255.255.255.0) 0 and 255 are both reserved addresses (network and broadcast), so you can only use 1 to 254
    Possibly worth mentioning DHCP reservation, I do this so my devices don't change addresses
    Those IP address ranges you mentioned are RFC1597 addresses and are specifically designed as private (non-routable) addresses, don't go randomly picking a subnet to use.
     
  5. keithsw1111

    keithsw1111 Full Time Elf

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    Your unicast resources comment would almost never be true unless you had multiple controllers sharing a single universe. I think I have only ever seen one user do that. I wouldn’t mention it on that basis.
     
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  6. AntinOz

    AntinOz New Elf

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    Thanks, I stand corrected, know a lot more about networking than I do about lighting!
     
  7. Derf

    Derf Full Time Elf Generous Elf

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    Sounds Good Alan.

    Just when this is implimented I would recommend stating that understanding basic networking is highly recommended. Just from facebook as a general survey people are having issues with ip ranges and how netmasks are implemented into a network. I would suggest basic breakdown diagrams for this topic to make it stand out whilst people are reading the manual.
    Using basic terminology and not dumping technical jargon all out at once then having an equivilent example below or above the information. For example IP addresses: have 2 diagrams one saying there is a router and a controller and naming them "router" and "Falcon f16v3" then explaing there has to be a unique identifier to locate a device and then introduce the Internet protocol. Then have the second diagram showing the router and falcon with assigned ip addresses.

    I am currently whipping up a few small animations on how multicast and unicast data flows as this will be the easiest way to show new users how this type of networking works.

    Thanks
    Derf | Jack
     
  8. David_AVD

    David_AVD Bite my shiny metal ass! Community Project Designer Generous Elf

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    I think a lot of the networking stuff should go in the wiki / forums. Trying to cram it all into the 101 is not the best way imo.
     
  9. OP
    OP
    AAH

    AAH I love blinky lights :) Community Project Designer Generous Elf

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    There is 1 thing I noticed on a read through tonight was that 1 of the suggested tools in the 101 is a multimeter. I suggested to Ryan that it would be good if there was a good video on how to use a multimeter for testing as noobs may not know the settings required for Volts, Amps, Continuity, AC/DC or what leads plug into where for those measurements.
    Maybe @JeffL98 could knock 1 up over the weekend :D
     
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