E1.31 : Discovery Packet

Arjan van Vught

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Oct 21, 2016, 2:35:40 PM10/21/16

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Hello group,

I am reading the document "BSR E1.31 — 201x Entertainment Technology Lightweight streaming protocol for transport of DMX512 using ACN", Revision 1.15 02 Jan 2016.

The Root Vector must be VECTOR_ROOT_E131_EXTENDED. Which is defined as 0x00000008.

I have olad/Olad.cpp:94: OLA Daemon version 0.10.2 running on my Raspberry Pi. And investigating the Discovery Packet with Wireshark :

Frame 150522: 159 bytes on wire (1272 bits), 159 bytes captured (1272 bits) on interface 0
Ethernet II, Src: Raspberr_92:c8:80 (b8:27:eb:92:c8:80), Dst: IPv4mcast_7f:fa:d6 (01:00:5e:7f:fa:d6)
Internet Protocol Version 4, Src: 192.168.2.129, Dst: 239.255.250.214
User Datagram Protocol, Src Port: 5568, Dst Port: 5568
Architecture for Control Networks
    Size of preamble: 16
    Size of postamble: 0
    Packet Identifier: ASC-E1.17
    PDU: Root DMX, Src: 3c7d3509-67b9-4671-bf0f-02ed95c16540
        Flags: 0x70
            0... .... = Length: False
            .1.. .... = Vector: True
            ..1. .... = Header: True
            ...1 .... = Data: True
        Length: 101
        Protocol ID: Ratified DMX Protocol (4)
        CID: 3c7d3509-67b9-4671-bf0f-02ed95c16540
        PDU: not valid (4)
            Flags: 0x70
                0... .... = Length: False
                .1.. .... = Vector: True
                ..1. .... = Header: True
                ...1 .... = Data: True
            Length: 79
            Vector: Unknown (4)

Is this draft version supported in OLA 0.10.2 ?

Thanks, Arjan

http://www.raspberrypi-dmx.org/

Andrew Frazer

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Oct 21, 2016, 2:45:37 PM10/21/16

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FYI I would refer to the lastest published standard which is completely up up date

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Peter Newman

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Oct 21, 2016, 4:34:44 PM10/21/16

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As far as I can work out, there was a draft discovery standard at one point, which OLA supports:

https://github.com/OpenLightingProject/ola/pull/472

This seems to use the standard E1.31 ACN Root vector and then just a custom E1.31 vector. In comparison, the 2016 standard has a new E1.31 extended ACN root vector, and then a new E1.31 discovery vector.

So OLA probably needs to add an option to support the new or draft E1.31 discovery protocols and the relevant code changes.

In terms of your Wireshark log, we're therefore sending the E1.31 ACN Root vector "Ratified DMX Protocol (4)", but the old E1.31 (rather than E1.31 Extended) discovery data vector.

On Friday, 21 October 2016 19:45:37 UTC+1, mrpackethead wrote:

FYI I would refer to the lastest published standard which is completely up up date

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Andrew Frazer

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Oct 21, 2016, 5:59:57 PM10/21/16

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Yes things changed. I suggest OLA removes all references to the draft and ONLY supports the published standards. If you run draft stuff you need to understand it is liable to change before it's published

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Arjan van Vught

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Oct 22, 2016, 9:51:13 AM10/22/16

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Hi Andrew, please will you provide the link to the latest published standard.

Thanks, Arjan
http://www.raspberrypi-dmx.org

Op 21-10-2016 om 20:45 schreef Andrew Frazer:

Arjan van Vught

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Oct 22, 2016, 9:51:13 AM10/22/16

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Hi Andrew,

I am reading the latest standard and it looks to me that OLA 0.10.2 does not adhere to the latest standard. Is this a correct observation ?

Thanks, Arjan

Op 21-10-2016 om 20:45 schreef Andrew Frazer:

FYI I would refer to the lastest published standard which is completely up up date

Peter Newman

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Oct 22, 2016, 9:56:12 AM10/22/16

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Correct https://github.com/OpenLightingProject/ola/issues/1139

On Saturday, 22 October 2016 14:51:13 UTC+1, Arjan van Vught wrote:

Hi Andrew,

I am reading the latest standard and it looks to me that OLA 0.10.2 does not adhere to the latest standard. Is this a correct observation ?

Thanks, Arjan

Op 21-10-2016 om 20:45 schreef Andrew Frazer:

FYI I would refer to the lastest published standard which is completely up up date

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Andrew Frazer

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Oct 22, 2016, 12:40:17 PM10/22/16

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It was published about a week ago, so its very new.. however it is online.

ANSI E1.31 - 2016, Entertainment Technology - Lightweight streaming protocol for transport of DMX512 using ACN, is a revision of the 2009 standard. It describes a mechanism to transfer DMX512A packets over a TCP/IP network using a subset of the ACN protocol suite. It covers data format, data protocol, data addressing, and network management It also outlines a synchronization method to help ensure that multiple sinks can process this data concurrently when supervised by the same controller. This revision includes DMX512 universe synchronization.

http://tsp.esta.org/tsp/documents/published_docs.php

Arjan van Vught

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Oct 22, 2016, 3:16:00 PM10/22/16

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Thanks Andrew

I am almost ready implementing the new specification for the Raspberry Pi Zero/A+ Wifi sACN E1.31 Bridge -> http://www.raspberrypi-dmx.org/raspberry-pi-e131-wifi-bridge

The updated source is not pushed to Github, yet. The implementation for the previous specification -> https://github.com/vanvught/rpidmx512/tree/master/lib-e131

As Wireshark is not known with the new specification, I have written a Java tool for sniffering the Discocery packages. So far, it looks good.

It would be great to have OLA for doing more testing before making a new release.

Thanks, Arjan

Op 22-10-2016 om 18:40 schreef Andrew Frazer:

Peter Newman

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Oct 22, 2016, 5:47:28 PM10/22/16

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I see you've pushed now. Technically that's the 2016 variant, rather than 2009.

https://github.com/vanvught/rpidmx512/commit/0c35f4e4d833765420558f1433ce7f71bc8f00cd#diff-b210e04e8f674fd65d5f215f8b4b3abd

I'd agree, the main Wireshark code doesn't seem to handle the new version yet.

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Arjan van Vught

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Oct 23, 2016, 7:08:20 AM10/23/16

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Hi Peter,

The commit you are referring to is the full implementation of the 2009 specifications.

I am not sure why the Discovery function is in it. It shouldn't be, my mistake. I was just prototyping as I noticed that both OLA and sACN Viewer supports Discovery. My apologize for the confusing in the code.

- Arjan

Op 22-10-2016 om 23:47 schreef Peter Newman:

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Peter Newman

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Oct 23, 2016, 7:30:32 AM10/23/16

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Ah yes, I see that although you're defining the 2016 E1.31 extended root vector for 2016 discovery, you're not actually using it yet.

Arjan van Vught

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Oct 23, 2016, 11:43:30 AM10/23/16

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I have made the E131 Discovery Sniffer available here -> https://github.com/vanvught/rpidmx512/tree/master/E131

It is a simple Java utility which joins the group "239.255.250.214" (131_DISCOVERY_UNIVERSE 64214) and dumps the Discovery packet in an easy to read format.

Sample output :

Sun, 23 Oct 2016 12:48:57 CEST /192.168.2.134 [122]
Preamble size : 0010
Post size : 0000
ACN Packet id : ASC-E1.17
Flags and Length : 707a[122]
Vector : 00000008
CID : 54154852-f21f-4ec3-bba8-fec6cf37c
Flags and Length : 7054[84]
Vector : 00000002
Source Name : Raspberry Pi Wifi sACN E1.31 http://www.raspberrypi-dmx.org....
Flags and Length : 700a[10]
Vector : 00000001
Page : 00
Last Page : 00
Universe list entries : 1
0001

- Arjan

Op 23-10-2016 om 13:30 schreef Peter Newman:

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Naohiro Higashida

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Nov 17, 2016, 7:43:05 AM11/17/16

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Hi Arjan.

ANSI E1.31-2016 Section 5.4
"The RLP PDU length is computed starting with octet 16 and counting all octets in the packet."

I think RLP PDU length is 106 at your sample.

I'm not good at Reading & Writing English, I am sorry if it was my misunderstanding.

2016年10月24日月曜日 0時43分30秒 UTC+9 Arjan van Vught:

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