Manual

84
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In BRIC Normal mode, the default mode of operaon, NX transfers all its audio data via the UDP protocol. This is in
contrast to most web-based connecons, such as web browsing and e-mail. These use TCP protocol. UDP, unlike TCP, is
not “connecon oriented”; that is, no virtual connecon actually exists in this protocol layer between the devices.
In UDP, the transmier simply launches packets into the network with the correct address, hoping the network will
deliver the packets in a mely fashion. Since there is no intelligent connecon built between the codecs, there isn’t
actually any connecon to break in the event of network failure.
If a packet is delayed or lost, no error message is sent and no packets are retransmied. It is up to the receiver to cover
up any lost data, if it can. This allows delivery of the packets with the smallest amount of overhead and delay.
Therefore, the usability of the network is the important factor, not the existence of a physical connecon. Loss of the
remote will usually be due to a network failure. (If the network fails and is later restored, the packets stream will be
restored to the decoder.)
For most applicaons, such as remote broadcasng, it’s useful to simulate a connecon-oriented stream, so NX uses a
low-bandwidth sub channel to deliver informaon back to the encoder about overall connecon status. It does this in its
“applicaon layer”, rather than the “transport layer”, which is where UDP exists.
By default, it monitors the health of a connecon. If no data is detected as received by the decoder during the preset
user adjustable meout, it “tears down” this connecon and goes back to idle state. This can give an indicaon to the
user that the network has failed and it’s me to look at the problem.
The good thing about having the connecon protocol in the applicaon layer is that its use is oponal. For 24/7
operaon, there’s no advantage to having the connecon end if no data is received for a meout interval.
To set NX for 24/7 operaon, several parameters are changed:
1 The meout value is set to innity - the connecon will never be torn down regardless of data.
2 NX is congured to re-establish the connecon in the event of a power re-cycling.
3 The local Disconnect control is disabled. The Disconnect funcon on the receiving side is sll en-
abled, but will result in an immediate reconnecon by the iniang side.