Re: [LCtalk] LanBox UDP disclosed

[Matthijs van Duin]

A bit better explanation of announce vs write messages:


A write message says to the receiving LanBox: "write this data into the 
specified buffer".  It is an active "push"-model of data transfer, and 
the lanbox will accept it as long as it's from the configured UDP-In IP 
address, and the target buffer+channelrange exists and is writeable.

An announce message instead says:  "Here is (part of) the contents of 
one of my (the sender's) buffers... do with it whatever you like".  The 
lanbox can in particular be configured to accept mixer data (buffer 254) 
from other lanboxes and copy (parts of) it into the mixer or a layer.


Typically an announce message is broadcast (sent to every device on the 
network), informing every receipient about your (the sender's) buffer, 
while the recipient decides what to do with this data, if anything.

Typically a write message is unicast (sent to one device), directly 
writing into a buffer of the recipient lanbox.  The recipient can only 
decide whether to accept the message, but doesn't do any mapping.

Note that you can unicast an announce message or broadcast a write 
message, but neither of these are likely to be useful.


Announce messages for buffers other than 254 are perfectly valid, but 
the LanBox currently just ignores any such messages received.  Other 
software applications may care about them though.


A list of all buffer IDs:

0        <Invalid for UDP - current/no layer>
1-26     Layers A - Z
27-52    Layers AA - AZ
53-63    Layers BA - BK
64       <Invalid for UDP - create new layer>
65-127   <Invalid for UDP - internal use only>
128-251  <Reserved for future use>
252      DMX Input
253      External Inputs
254      Mixer
255      DMX Output

--
Matthijs van Duin  --  May the Forth be with you!