diff options
2 files changed, 18 insertions, 6 deletions
diff --git a/interfaces.tex b/interfaces.tex
index 72f9651..c1bab47 100644
--- a/interfaces.tex
+++ b/interfaces.tex
@@ -122,8 +122,8 @@ section~\ref{sec:zeromq} below.}.
EDI can be carried over UDP or other unreliable links, and offers a protection
layer to correct bit-errors. Over network connections where the occasional
congestion can occur, EDI can also be carried over TCP, which will ensure lost
-packets get retransmit. Unless you are able to reserve bandwidth for the EDI
-traffic, using TCP is the safer option.
+packets get retransmitted. Unless you are able to guarantee reserved bandwidth
+for the EDI traffic, using TCP is the safer option.
While the main reason to use EDI is to put the different tools on different
computers, it is not necessary to do so.
@@ -135,7 +135,9 @@ same machine, for increased flexibility.
Between ODR-AudioEnc and ODR-DabMux, the EDI protocol carries \dabplus{}
superframes or DAB frames, with additional metadata that contains the audio
-level indication for monitoring purposes.
+level indication, a version field and a free-form identifier string for
+monitoring purposes.\footnote{This metadata is carried in the custom EDI TAGs
+\texttt{ODRv} and \texttt{ODRa}.}
The multiplexer cannot easily derive the audio level from the encoded bitstream
without decoding it, so it makes more sense to calculate this in the encoder and
carry it along the encoded data.
@@ -241,6 +243,11 @@ by third parties. Usually, some form of VPN is set up for this case.
The EDI protocol can also carry data of a complete ensemble from ODR-DabMux to
one or more instanced of ODR-DabMod.
+In case you with to interface ODR-DabMux with a modulator that does not support
+EDI over TCP, but your network is not stable enough to use UDP, you can use
+ODR-EDI2EDI. See \url{http://github.com/Opendigitalradio/ODR-EDI2EDI} for
+information about that tool.
Previous versions of this guide described an IP protocol based on
diff --git a/systemenvironments.tex b/systemenvironments.tex
index 1267c0d..14e656f 100644
--- a/systemenvironments.tex
+++ b/systemenvironments.tex
@@ -146,13 +146,18 @@ synchronised to the clock time which is being transmitted by the multiplex to
which it has been tuned.
The system needs to run a NTP client that synchronises the system time over the
-network. Correct synchronisation can be checked using the \texttt{lpeers}
-command of the \texttt{ntpq} tool. The magnitude of the offset should be below
+network. Correct synchronisation can be checked using \texttt{chronyc tracking}
+or the the \texttt{lpeers} command of the \texttt{ntpq} tool, depending on if
+you use chrony or openntp.
+The magnitude of the offset should be below $10$\ms.
The performance of the NTP synchronisation should also be monitored permanently
during operation.
+ODR-DabMux can run a command at startup to verify if the NTP client is properly
+working, using the \texttt{startupcheck} setting. This can be used to call
+\texttt{ntp-wait} or \texttt{chronyc waitsync} to wait for proper NTP sync.
\subsection{Monitoring through SNMP}
There is ongoing work to make the monitoring of the tools possible using SNMP.
Please see \url{https://wiki.opendigitalradio.org/SNMP} for information about