From 721dc8d34ace3825fbbf3bc2b0d9bc77128f0df0 Mon Sep 17 00:00:00 2001
From: Donat Zenichev <dzenichev@sipwise.com>
Date: Thu, 13 Apr 2023 10:54:40 +0200
Subject: [PATCH] MT#55897 Move 'daemon/rtpengine.pod' to 'docs/'

Due to a unification of the way we store documentation files,
the 'rtpengine.pod' has been moved to the 'docs/' folder.

This 'docs/rtpengine.pod' will be later used for the RTD a source.

Change-Id: Iba9d77e397c042f7d84e8e51d2367b42ecb5b07c
---
 daemon/rtpengine.pod | 1366 +-----------------------------------------
 docs/rtpengine.pod   | 1365 +++++++++++++++++++++++++++++++++++++++++
 2 files changed, 1366 insertions(+), 1365 deletions(-)
 mode change 100644 => 120000 daemon/rtpengine.pod
 create mode 100644 docs/rtpengine.pod

diff --git a/daemon/rtpengine.pod b/daemon/rtpengine.pod
deleted file mode 100644
index 5dc098fb0..000000000
--- a/daemon/rtpengine.pod
+++ /dev/null
@@ -1,1365 +0,0 @@
-=head1 NAME
-
-rtpengine - NGCP proxy for RTP and other UDP based media traffic
-
-=head1 SYNOPSIS
-
-B<rtpengine> B<--interface>=I<addr>... B<--listen-tcp>|B<--listen-udp>|B<--listen-ng>|B<--listen-tcp-ng>|B<--listen-http>|B<--listen-https>=I<addr>... [I<option>...]
-
-=head1 DESCRIPTION
-
-The Sipwise NGCP rtpengine is a proxy for RTP traffic and other UDP based
-media traffic.
-It is meant to be used with the Kamailio SIP proxy and forms a drop-in
-replacement for any of the other available RTP and media proxies.
-
-=head1 OPTIONS
-
-Most of these options are indeed optional, with two exceptions. It's
-mandatory to specify at least one local IP address through B<--interface>,
-and at least one of the B<--listen->I<...> options must be given.
-
-All options can (and should) be provided in a config file instead of
-at the command line. See the B<--config-file> option below for details.
-
-=over 4
-
-=item B<--help>
-
-Print the usage information.
-
-=item B<-v>, B<--version>
-
-If called with this option, the B<rtpengine> daemon will simply print its
-version number and exit.
-
-=item B<--codecs>
-
-Print a list of supported codecs and exit.
-
-=item B<--config-file=>I<FILE>
-
-Specifies the location of a config file to be used. The config file is an
-I<.ini> style config file, with all command-line options listed here also
-being valid options in the config file.
-For all command-line options, the long name version instead of the
-single-character version (e.g. B<table> instead of just B<t>) must be
-used in the config file.
-For boolean options that are either present or not (e.g. B<no-fallback>), a
-boolean value (either B<true> or B<false>) must be used in the config file.
-If an option is given in both the config file and at the command line,
-the command-line value overrides the value from the config file.
-Options that can be specified multiple times on the command line must be
-given only once in the config file, with the multiple values separated by
-semicolons (see section L<INTERFACES> below for an example).
-
-As a special value, B<none> can be passed here to suppress loading of the
-default config file F</etc/rtpengine/rtpengine.conf>.
-
-=item B<--config-section=>I<STRING>
-
-Specifies the I<.ini> style section to be used in the config file.
-Multiple sections can be present in the config file, but only one can be
-used at a time.
-The default value is B<rtpengine>.
-A config file section is started in the config file using square brackets
-(e.g. B<[rtpengine]>).
-
-=item B<-t>, B<--table=>I<INT>
-
-Takes an integer argument and specifies which kernel table to use for
-in-kernel packet forwarding.
-See the section on in-kernel operation in the F<README.md> for more detail.
-Optional and defaults to zero.
-If in-kernel operation is not desired, a negative number can be specified.
-
-=item B<-F>, B<--no-fallback>
-
-Will prevent fallback to userspace-only operation if the kernel module is
-unavailable.
-In this case, startup of the daemon will fail with an error if this option
-is given.
-
-=item B<-S>, B<--save-interface-ports>
-
-Will bind ports only on the first available local interface, of desired
-family, of logical interface. If no ports available on any local interface
-of desired family, give an error message.
-
-In this case, ICE will be broken.
-
-=item B<-i>, B<--interface=>[I<NAME>B</>]I<IP>[B<!>I<IP>]
-
-Specifies a local network interface for RTP.
-At least one must be given, but multiple can be specified.
-See the section L<INTERFACES> just below for details.
-
-=item B<-l>, B<--listen-tcp=>[I<IP>B<:>]I<PORT>
-
-=item B<-u>, B<--listen-udp=>[I<IP46>B<:>]I<PORT>
-
-=item B<-n>, B<--listen-ng=>[I<IP46>B<:>]I<PORT>
-
-=item B<-n>, B<--listen-tcp-ng=>[I<IP46>B<:>]I<PORT>
-
-These options each enable one of the 4 available control protocols if given
-and each take either just a port number as argument, or an I<address:port>
-pair, separated by colon.
-At least one of these 3 options must be given.
-
-The B<tcp> protocol is obsolete.
-It was used by old versions of B<OpenSER> and its B<mediaproxy> module.
-It is provided for backwards compatibility.
-
-The B<udp> protocol is used by B<Kamailio>'s B<rtpproxy> module.
-In this mode, B<rtpengine> can be used as a drop-in replacement for any
-other compatible RTP proxy.
-
-The B<ng> protocol is an advanced control protocol and can be used with
-B<Kamailio>'s B<rtpengine> module.
-With this protocol, the complete SDP body is passed to B<rtpengine>,
-rewritten and passed back to B<Kamailio>.
-Several additional features are available with this protocol, such as
-ICE handling, SRTP bridging, etc.
-
-The B<tcp-ng> protocol is in fact the B<ng> protocol but transported over TCP.
-
-It is recommended to specify not only a local port number, but also
-B<127.0.0.1> as interface to bind to.
-
-=item B<-c>, B<--listen-cli=>[I<IP46>:]I<PORT>
-
-TCP ip and port to listen for the CLI (command line interface).
-
-=item B<-g>, B<--graphite=>I<IP46>:I<PORT>
-
-Address of the graphite statistics server.
-
-=item B<-w>, B<--graphite-interval=>I<INT>
-
-Interval of the time when information is sent to the graphite server.
-
-=item B<--graphite-prefix=>I<STRING>
-
-Add a prefix for every graphite line.
-
-=item B<--graphite-timeout=>I<INT>
-
-Sets after how much time (seconds) to force fail graphite socket connection,
-when graphite server is filtered out. If set to 0, there are no changes.
-
-=item B<-t>, B<--tos=>I<INT>
-
-Takes an integer as argument and if given, specifies the TOS value that
-should be set in outgoing packets.
-The default is to leave the TOS field untouched.
-A typical value is 184 (B<Expedited Forwarding>).
-
-=item B<--control-tos=>I<INT>
-
-Takes an integer as argument and if given, specifies the TOS value that
-should be set in the control-ng interface packets.
-The default is to leave the TOS field untouched.
-This parameter can also be set or listed via B<rtpengine-ctl>.
-
-=item B<--control-pmtu=>B<want>|B<dont>
-
-Forces a specific PMTU discovery behaviour on IPv4 UDP control sockets,
-overriding the system-wide default. If set to B<want> then path MTU discovery
-is performed, initially enabling the DF (don't fragment) bit on outgoing IPv4
-packets until the path MTU has been discovered through reception of a
-"fragmentation needed" ICMP packet. If set to B<dont> then path MTU discovery
-is disabled, leaving the DF bit unset, and relying on the routers within the
-network path to perform any necessary fragmentation.
-
-The setting of B<dont> is useful in broken IPv4 environments without
-functioning PMTU discovery, for example in networks which unconditionally block
-all ICMP.
-
-=item B<-o>, B<--timeout=>I<SECS>
-
-Takes the number of seconds as argument after which a media stream should
-be considered dead if no media traffic has been received.
-If all media streams belonging to a particular call go dead, then the call
-is removed from B<rtpengine>'s internal state table.
-Defaults to 60 seconds.
-
-=item B<-s>, B<--silent-timeout=>I<SECS>
-
-Ditto as the B<--timeout> option, but applies to muted or inactive media
-streams.
-Defaults to 3600 (one hour).
-
-=item B<-a>, B<--final-timeout=>I<SECS>
-
-The number of seconds since call creation, after call is deleted.
-Useful for limiting the lifetime of a call.
-This feature can be disabled by setting the parameter to 0.
-By default this timeout is disabled.
-
-=item B<--offer-timeout=>I<SECS>
-
-This timeout (in seconds) is applied to calls which only had an B<offer>
-but no B<answer>.
-Defaults to 3600 (one hour).
-
-=item B<-p>, B<--pidfile=>I<FILE>
-
-Specifies a path and file name to write the daemon's PID number to.
-
-=item B<-f>, B<--foreground>
-
-If given, prevents the daemon from daemonizing, meaning it will stay in
-the foreground.
-Useful for debugging.
-
-=item B<-m>, B<--port-min=>I<INT>
-
-=item B<-M>, B<--port-max=>I<INT>
-
-Both take an integer as argument and together define the local port range
-from which B<rtpengine> will allocate UDP ports for media traffic relay.
-Default to 30000 and 40000 respectively.
-
-=item B<-L>, B<--log-level=>I<INT>
-
-Takes an integer as argument and controls the highest log level which will be
-sent to syslog. This is merely the default log level used for logging
-subsystems (see below) that don't explicitly have a separate log level
-configured.
-
-The log levels correspond to the ones found in the L<syslog(3)> man page.
-The default value is B<6>, equivalent to LOG_INFO.
-The highest possible value is B<7> (LOG_DEBUG) which will log everything.
-
-During runtime, the log level can be decreased by sending the signal
-SIGURS1 to the daemon and can be increased with the signal SIGUSR2.
-
-=item B<--log-level->I<subsystem>B<=>I<INT>
-
-Configures a log level for one of the logging subsystems. A logging subsystem
-which doesn't have a log level configured explicitly takes its default value
-from the B<log-level> setting described above, with the exception of the
-B<internals> subsystem which by default has all logging disabled.
-
-The full list of logging subsystems can be viewed by pulling up the B<--help>
-online help. Some (if not all) subsystems are: B<core>, B<spandsp> (messages
-generated by SpanDSP itself), B<ffmpeg> (messages generated by ffmpeg libraries
-themselves), B<transcoding> (messages related to RTP/media transcoding),
-B<codec> (messages related to codec negotiation), B<rtcp>, B<ice>, B<crypto>
-(messages related to crypto/SRTP/SDES/DTLS negotiation), B<srtp> (messages
-related to RTP/SRTP en/decryption), B<internals> (disabled by default), B<http>
-(includes WebSocket), B<control> (messages related to control protocols,
-including SDP exchanges), B<dtx>.
-
-=item B<--log-facilty=>B<daemon>|B<local0>|...|B<local7>|...
-
-The syslog facilty to use when sending log messages to the syslog daemon.
-Defaults to B<daemon>.
-
-=item B<--log-facilty-cdr=>B<daemon>|B<local0>|...|B<local7>|...
-
-Same as B<--log-facility> with the difference that only CDRs are written
-to this log facility.
-
-=item B<--log-facilty-rtcp=>B<daemon>|B<local0>|...|B<local7>|...
-
-Same as B<--log-facility> with the difference that only RTCP data is
-written to this log facility.
-Be careful with this parameter since there may be a lot of information
-written to it.
-
-=item B<--log-facilty-dtmf=>B<daemon>|B<local0>|...|B<local7>|...
-
-Same as B<--log-facility> with the difference that only DTMF events are
-written to this log facility.
-DTMF events are extracted from RTP packets conforming to RFC 4733, are
-encoded in JSON format, and written as soon as the end of an event is
-detected.
-
-=item B<--log-format=>B<default>|B<parsable>
-
-Selects between multiple log output styles.
-The default is to prefix log lines with a description of the relevant
-entity, such as B<[CALLID]> or B<[CALLID port 12345]>.
-The B<parsable> output style is similar, but makes the ID easier to
-parse by enclosing it in quotes, such as B<[ID="CALLID"]>
-or B<[ID="CALLID" port="12345"]>.
-
-=item B<--dtmf-log-dest=>I<IP46>:I<PORT>
-
-Configures a target address for logging detected DTMF event. Similar
-to the feature enabled by B<--log-facilty-dtmf>, but instead of writing
-detected DTMF events to syslog, this sends the JSON payload to the
-given address as UDP packets.
-
-=item B<--dtmf-log-ng-tcp>
-
-If B<--listen-tcp-ng> is enabled, this will send DTMF events to all
-connected clients encoded in bencode format.
-
-=item B<--dtmf-no-log-injects>
-If B<--dtmf-no-log-injects> is enabled, DTMF events resulting from a
-call to inject-DTMF won't be sent to B<--dtmf-log-dest=> or B<--listen-tcp-ng>
-
-=item B<--dtmf-no-suppress>
-
-Some RTP clients continue to send audio RTP packets during a DTMF event,
-resulting in both audio packets and DTMF packets appearing simultaneously. By
-default, when transcoding, B<rtpengine> suppresses audio packets during a DTMF
-event and will only send DTMF packets until the DTMF event is over. Setting
-this option disables this feature.
-
-=item B<--log-srtp-keys>
-
-Write SRTP keys to error log instead of debug log.
-
-=item B<-E>, B<--log-stderr>
-
-Log to stderr instead of syslog.
-Only useful in combination with B<--foreground>.
-
-=item B<--split-logs>
-
-Split multi-line log messages into individual log messages so that each
-line receives its own log line prefix.
-
-=item B<--max-log-line-length=>I<INT>
-
-Split log lines into multiple lines when they exceed the character count given
-here. Can be set to a negative value to allow unlimited length log lines. Set
-to zero for the default value, which is unlimited if logging to stderr, or 500
-if logging to syslog.
-
-=item B<--no-log-timestamps>
-
-Don't add timestamps to log lines written to stderr.
-Only useful in combination with B<--log-stderr>.
-
-=item B<--log-name=>I<STRING>
-
-Set the id to be printed in syslog.
-Defaults to B<rtpengine>.
-
-=item B<--log-mark-prefix=>I<STRING>
-
-Prefix to be added to particular data fields in log files that are deemed
-sensitive and/or private information. Defaults to an empty string.
-
-=item B<--log-mark-suffix=>I<STRING>
-
-Suffix to be added to particular data fields in log files that are deemed
-sensitive and/or private information. Defaults to an empty string.
-
-=item B<--num-threads=>I<INT>
-
-How many worker threads to create, must be at least one.
-The default is to create as many threads as there are CPU cores available.
-If the number of CPU cores cannot be determined or if it is less than four,
-then the default is four.
-
-=item B<--media-num-threads=>I<INT>
-
-Number of threads to launch for media playback. Defaults to the same
-number as B<num-threads>. This can be set to zero if no media playback
-functionality is desired.
-
-Media playback is actually handled by two threads: One for reading and
-decoding the media file, and another to schedule and send out RTP packets.
-So for example, if this option is set to 4, in total 8 threads will be
-launched.
-
-=item B<--thread-stack=>I<INT>
-
-Set the stack size of each thread to the value given in kB. Defaults to 2048
-kB. Can be set to -1 to leave the default provided by the OS unchanged.
-
-=item B<--evs-lib-path=>I<FILE>
-
-Points to the shared object file (B<.so>) containing the reference
-implementation for the EVS codec. See the F<README> for more details.
-
-=item B<--sip-source>
-
-The original B<rtpproxy> as well as older version of B<rtpengine> by default
-did not honour IP addresses given in the SDP body, and instead used the
-source address of the received SIP message as default endpoint address.
-Newer versions of B<rtpengine> reverse this behaviour and honour the
-addresses given in the SDP body by default. This option restores the
-old behaviour.
-
-=item B<--dtls-passive>
-
-Enables the B<DTLS=passive> flag for all calls unconditionally.
-
-=item B<-d>, B<--delete-delay=>I<INT>
-
-Delete the call after the specified delay from memory.
-Can be set to zero for immediate call deletion.
-
-=item B<-r>, B<--redis=>[I<PW>B<@>]I<IP>B<:>I<PORT>B</>I<INT>
-
-Connect to specified Redis database (with the given database number) and
-use it for persistence storage.
-The format of this option is I<ADDRESS>:I<PORT>/I<DBNUM>, for example
-I<127.0.0.1:6379/12> to connect to the Redis DB number 12 running on
-localhost on the default Redis port.
-
-If the Redis database is protected with an authentication password, the
-password can be supplied by prefixing the argument value with the password,
-separated by an B<@> symbol, for example I<foobar@127.0.0.1:6379/12>.
-Note that this leaves the password visible in the process list, posing a
-security risk if untrusted users access the same system.
-As an alternative, the password can also be supplied in the shell
-environment through the environment variable B<RTPENGINE_REDIS_AUTH_PW>.
-
-On startup, B<rtpengine> will read the contents of this database and
-restore all calls stored therein.
-During runtime operation, B<rtpengine> will continually update the
-database's contents to keep it current, so that in case of a service
-disruption, the last state can be restored upon a restart.
-
-When this option is given, B<rtpengine> will delay startup until the
-Redis database adopts the master role (but see below).
-
-=item B<-w>, B<--redis-write=>[I<PW>B<@>]I<IP>B<:>I<PORT>B</>I<INT>
-
-Configures a second Redis database for write operations.
-If this option is given in addition to the first one, then the first
-database will be used for read operations (i.e. to restore calls from)
-while the second one will be used for write operations (to update states
-in the database).
-
-For password protected Redis servers, the environment variable for the
-password is B<RTPENGINE_REDIS_WRITE_AUTH_PW>.
-
-When both options are given, B<rtpengine> will start and use the Redis
-database regardless of the database's role (master or slave).
-
-=item B<-k>, B<--subscribe-keyspace=>I<INT>
-
-List of redis keyspaces to subscribe.
-If this is not present, no keyspaces are subscribed (default behaviour).
-Further subscriptions could be added/removed via B<rtpengine-ctl ksadd/ksrm>.
-This may lead to enabling/disabling of the redis keyspace notification feature.
-
-=item B<--redis-num-threads=>I<INT>
-
-How many redis restore threads to create.
-The default is 4.
-
-=item B<--redis-expires=>I<INT>
-
-Expire time in seconds for redis keys.
-Default is 86400.
-
-=item B<--active-switchover>
-
-With this option enabled, any activity (such as signalling or media) on a call
-that was created through a Redis keyspace notification will make B<rtpengine>
-take control of that call. Without this option, an explicit command is required
-for B<rtpengine> to take (or relinquish) control of a call.
-
-=item B<-q>, B<--no-redis-required>
-
-When this parameter is present or B<NO_REDIS_REQUIRED='yes'> or B<'1'> in
-the config file, B<rtpengine> starts even if there is no initial connection
-to redis databases (either to B<-r> or to B<-w> or to both redis).
-
-Be aware that if the B<-r> redis cannot be initially connected, sessions
-are not reloaded upon rtpengine startup, even though rtpengine still starts.
-
-=item B<--redis-allowed-errors>
-
-If this parameter is present and has a value >= 0, it will configure how
-many consecutive errors are allowed when communicating with a redis server
-before the redis communication will be temporarily disabled for that server.
-While the communication is disabled there will be no attempts to reconnect
-to redis or send commands to that server.
-Default value is -1, meaning that this feature is disabled.
-This parameter can also be set or listed via B<rtpengine-ctl>.
-
-=item B<--redis-disable-time>
-
-This parameter configures the number of seconds redis communication is
-disabled because of errors.
-This works together with redis-allowed-errors parameter.
-The default value is 10.
-This parameter can also be set or listed via B<rtpengine-ctl>.
-
-=item B<--redis-cmd-timeout=>I<INT>
-
-If this parameter is set to a non-zero value it will set the timeout,
-in milliseconds, for each command to the redis server.
-If redis does not reply within the specified timeout the command will fail.
-The default value is 0, meaning that the commands will be blocking without
-timeout.
-This parameter can also be set or listed via B<rtpengine-ctl>; note that
-setting the parameter to 0 will require a reconnect on all configured
-redis servers.
-
-=item B<--redis-connect-timeout=>I<INT>
-
-This parameter sets the timeout value, in milliseconds, when connecting
-to a redis server.
-If the connection cannot be made within the specified timeout the
-connection will fail.
-Note that in case of failure, when reconnecting to redis, a B<PING> command
-is issued before attempting to connect so the B<--redis-cmd-timeout> value
-will also be added to the total waiting time.
-This is useful if using B<--redis-allowed-errors>, when attempting to
-estimate the total lost time in case of redis failures.
-The default value for the connection timeout is 1000ms.
-This parameter can also be set or listed via B<rtpengine-ctl>.
-
-=item B<-b>, B<--b2b-url=>I<STRING>
-
-Enables and sets the URI for an XMLRPC callback to be made when a call is
-torn down due to packet timeout.
-The special code B<%%> can be used in place of an IP address, in which case
-the source address of the originating request (or alternatively the address
-specified using the B<xmlrpc-callback> B<ng> protocol option) will be used.
-
-=item B<-x>, B<--xmlrpc-format=>I<INT>
-
-Selects the internal format of the XMLRPC callback message for B2BUA call
-teardown.
-0 is for SEMS,
-1 is for a generic format containing the call-ID only,
-2 is for Kamailio.
-
-=item B<--max-sessions=>I<INT>
-
-Limit the number of maximum concurrent sessions.
-Set at startup via B<max-sessions> in config file.
-Set at runtime via B<rtpengine-ctl> util.
-Setting the B<rtpengine-ctl set maxsessions 0> can be used in draining
-rtpengine sessions.
-Enable feature: B<max-sessions=1000>
-Enable feature: B<rtpengine-ctl set maxsessions> >= 0
-Disable feature: B<rtpengine-ctl set maxsessions -1>
-By default, the feature is disabled (i.e. maxsessions == -1).
-
-=item B<--max-load=>I<FLOAT>
-
-If the current 1-minute load average exceeds the value given here,
-reject new sessions until the load average drops below the threshold.
-
-=item B<--max-cpu=>I<FLOAT>
-
-If the current CPU usage (in percent) exceeds the value given here,
-reject new sessions until the CPU usage drops below the threshold.
-CPU usage is sampled in 0.5-second intervals.
-Only supported on systems providing a Linux-style F</proc/stat>.
-
-=item B<--max-bandwidth=>I<INT>
-
-If the current bandwidth usage (in bytes per second) exceeds the value
-given here, reject new sessions until the bandwidth usage drops below
-the threshold.
-Bandwidth usage is sampled in 1-second intervals and is based on
-received packets, not sent packets.
-
-=item B<--homer=>I<IP46>B<:>I<PORT>
-
-Enables sending the decoded contents of RTCP packets to a Homer SIP
-capture server.
-The transport is HEP version 3 and payload format is JSON.
-This argument takes an IP address and a port number as value.
-
-=item B<--homer-protocol=>B<udp>|B<tcp>
-
-Can be either B<udp> or B<tcp> with B<udp> being the default.
-
-=item B<--homer-id=>I<INT>
-
-The HEP protocol used by Homer contains a "capture ID" used to distinguish
-different sources of capture data.
-This ID can be specified using this argument.
-
-=item B<--recording-dir=>I<FILE>
-
-An optional argument to specify a path to a directory where PCAP recording
-files and recording metadata files should be stored. If not specified,
-support for call recording will be disabled.
-
-B<rtpengine> supports multiple mechanisms for recording calls.
-See B<recording-method> below for a list.
-The default recording method B<pcap> is described in this section.
-
-PCAP files will be stored within a F<pcap> subdirectory and metadata
-within a F<metadata> subdirectory.
-
-The format for a metadata file is (with a trailing newline):
-
-	/path/to/recording-pcap.pcap
-
-	SDP mode: offer
-	SDP before RTP packet: 1
-
-	first SDP
-
-	SDP mode: answer
-	SDP before RTP packet: 1
-
-	second SDP
-
-	...
-
-	SDP mode: answer
-	SDP before RTP packet: 100
-
-	n-th and final SDP
-
-
-	start timestamp (YYYY-MM-DDThh:mm:ss)
-	end timestamp   (YYYY-MM-DDThh:mm:ss)
-
-
-	generic metadata
-
-There are two empty lines between each logic block of metadata.
-We write out all answer SDP, each separated from one another by one empty
-line.
-The generic metadata at the end can be any length with any number of
-lines.
-Metadata files will appear in the subdirectory when the call completes.
-PCAP files will be written to the subdirectory as the call is being
-recorded.
-
-Since call recording via this method happens entirely in userspace,
-in-kernel packet forwarding cannot be used for calls that are currently
-being recorded and packet forwarding will thus be done in userspace only.
-
-=item B<--recording-method=>B<pcap>|B<proc>|B<all>
-
-Multiple methods of call recording are supported and this option can be
-used to select one.
-Currently supported are the method B<pcap>, B<proc> and B<all>.
-The default method is B<pcap> and is the one described above.
-
-The recording method B<proc> works by writing metadata files directly into
-the B<recording-dir> (i.e. not into a subdirectory) and instead of recording
-RTP packet data into pcap files, the packet data is exposed via a special
-interface in the F</proc> filesystem.
-Packets must then be retrieved from this interface by a dedicated userspace
-component (usually a daemon such as recording-daemon included in this
-repository).
-
-Packet data is held in kernel memory until retrieved by the userspace
-component, but only a limited number of packets (default 10) per media
-stream.
-If packets are not retrieved in time, they will be simply discarded.
-This makes it possible to flag all calls to be recorded and then leave it
-to the userspace component to decided whether to use the packet data for
-any purpose or not.
-
-In-kernel packet forwarding is fully supported with this recording method
-even for calls being recorded.
-
-The recording method B<all> will enable both B<pcap> and B<proc>
-at the same time.
-
-=item B<--recording-format=>B<raw>|B<eth>
-
-When recording to pcap file in B<raw> (default) format, there is no
-ethernet header.
-When set to B<eth>, a fake ethernet header is added, making each package
-14 bytes larger.
-
-=item B<--record-egress>
-
-Apply media recording to egress media streams (as they are sent by
-B<rtpengine>) instead of media streams as they are received. This makes it
-possible to include manipulated and generated media (such as from the B<play
-media> command) in the recordings.
-
-=item B<--iptables-chain=>I<STRING>
-
-This option enables explicit management of an iptables chain.
-When enabled, B<rtpengine> takes control of the given iptables chain,
-which must exist already prior to starting the daemon.
-Upon startup, B<rtpengine> will flush the chain, and then add one B<ACCEPT>
-rule for each media port (RTP/RTCP) opened.
-Each rule will exactly match the individual port and destination IP address,
-and will be created with the call ID as iptables comment.
-The rule will be deleted when the port is closed.
-
-This option allows creating a firewall with a default B<DROP> policy for
-the entire port range used by B<rtpengine> and then referencing the given
-iptables chain to only selectively allow the ports actually in use.
-
-Note that this applies only to media ports, and does not apply to any other
-ports (such as the control ports) used by B<rtpengine>.
-
-Also note that the iptables API is not the most efficient one around and
-does not lend itself to fast dynamic creation and deletion of rules.
-If you have a high call volume, and especially many call attempts per
-second, you might experience significant performance impact.
-This is not a shortcoming of B<rtpengine> but rather of iptables and its
-API implementation in the Linux kernel.
-In such a case, it is recommended to add a static iptables rule for the
-entire media port range instead, and not use this option.
-
-=item B<--scheduling=>B<default>|...
-
-=item B<--priority=>I<INT>
-
-=item B<--idle-scheduling=>B<default>|...
-
-=item B<--idle-priority=>I<INT>
-
-These options control various thread scheduling parameters.
-The B<scheduling> and B<priority> settings are applied to the main
-worker threads, while the B<idle-> versions of these settings are
-applied to various lower priority threads, such as timer runs.
-
-The B<scheduling> settings take the name of one of the supported
-scheduler policies.
-Setting it to B<default> or B<none> is equivalent to not setting the
-option at all and leaves the system default in place.
-The strings B<fifo> and B<rr> refer to realtime scheduling policies.
-B<other> is the Linux default scheduling policy.
-B<batch> is similar to B<other> except for a small wake-up scheduling
-penalty.
-B<idle> is an extremely low priority scheduling policy.
-The Linux-specific B<deadline> policy is not supported by B<rtpengine>.
-Not all systems necessarily supports all scheduling policies; refer to
-your system's sched(7) man page for details.
-
-The B<priority> settings correspond to the scheduling priority for
-realtime (B<fifo> or B<rr>) scheduling policies and must be in the range
-of 1 (low) through 99 (high).
-For all other scheduling policies (including no policy specified), the
-B<priority> settings correspond to the B<nice> value and should be in
-the range of -20 (high) through 19 (low).
-Not all systems support thread-specific B<nice> values; on such a system,
-using these settings might have unexpected results.
-(Linux does support thread-specific B<nice> values.)
-Refer to your system's sched(7) man page.
-
-=item B<--mysql-host=>I<HOST>|I<IP>
-
-=item B<--mysql-port=>I<INT>
-
-=item B<--mysql-user=>I<USERNAME>
-
-=item B<--mysql-pass=>I<PASSWORD>
-
-Configuration for playing back media files that are stored in a
-B<MySQL> (or B<MariaDB>) database. At least B<mysql-host> must be configured
-for this to work. The others are optional and default to their respective
-values from the B<MySQL>/B<MariaDB> client library.
-
-=item B<--mysql-query=>I<STRING>
-
-Query to be used for retrieving media files from the database. No default
-exist, therefore this is a mandatory configuration for media playback from
-database. The provided query string must contain the single format placeholder
-B<%llu> and must not contain any other format placeholders. The ID value
-passed to B<rtpengine> in the B<db-id> key of the B<play media> message will
-be used in place of the placeholder when querying the database.
-
-An example configuration might look like this:
-
-  mysql-query = select data from voip.files where id = %llu
-
-=item B<--endpoint-learning=>B<delayed>|B<immediate>|B<off>|B<heuristic>
-
-Chooses one of the available algorithms to learn RTP endpoint addresses. The
-legacy setting is B<delayed> which waits 3 seconds before committing to an
-endpoint address, which is then learned from the first incoming RTP packet seen
-after this delay. The setting B<immediate> learns the endpoint address from the
-first incoming packet seen without the 3-second delay. Using B<off> disables
-endpoint learning altogether, likely breaking clients behind NAT. The setting
-B<heuristic> includes the 3-second delay, but source addresses seen from
-incoming RTP packets are ranked according to preference: If a packet with a
-source address and port matching the SDP address is seen, this address is used.
-Otherwise, if a packet with a matching source address (but a different port) is
-seen, that address is used. Otherwise, if a packet with a matching source port
-(but different address) is seen, that address is used. Otherwise, the source
-address of any incoming packet seen is used.
-
-=item B<--jitter-buffer=>I<INT>
-
-Size of (incoming) jitter buffer in packets. A value of zero (the default)
-disables the jitter buffer. The jitter buffer is currently only implemented for
-userspace operation.
-
-=item B<--jb-clock-drift>
-
-Enable clock drift compensation for the jitter buffer.
-
-=item B<--debug-srtp>
-
-Enable extra log messages to help debug SRTP issues. Per-packet details such as
-sequence numbers, ROC, payloads (plain text and encrypted), authentication
-tags, etc are recorded to the log. Every RTCP packet is logged in this way,
-while every 512th RTP packet is logged. Only applies to packets
-forwarded/processed in userspace.
-
-=item B<--reject-invalid-sdp>
-
-With this option set, refuse to process SDP bodies that could not be cleanly
-parsed, instead of skipping over the parsing error and processing the SDP
-anyway. Currently this only affects the processing of SDP bodies that end in a
-blank line.
-
-=item B<--listen-http=>[I<IP>|I<HOSTNAME>B<:>]I<PORT>
-
-=item B<--listen-https=>[I<IP>|I<HOSTNAME>B<:>]I<PORT>
-
-Enable listening for HTTP or WebSocket connections, or their TLS-secured
-counterparts HTTPS and WSS. If no interface is specified, then the listening
-socket will be bound to all interfaces.
-
-The HTTP listener supports both HTTP and WS, while the HTTPS listener supports
-both HTTPS and WSS.
-
-If HTTPS/WSS is enabled, a certificate must also be provided using the options
-below.
-
-=item B<--https-cert=>I<FILE>
-
-=item B<--https-key=>I<FILE>
-
-Provide a server certificate and corresponding private key for the HTTPS/WSS
-listener, in PEM format.
-
-=item B<--http-threads=>I<INT>
-
-Number of worker threads for HTTP/HTTPS/WS/WSS. If not specified, then the same
-number as given under B<num-threads> will be used. If no HTTP listeners are
-enabled, then no threads are created.
-
-=item B<--software-id=>I<STRING>
-
-Sets a free-form string that is used to identify this software towards external
-systems with, for example in outgoing ICE/STUN requests. Defaults to
-B<rtpengine->I<VERSION>. The string is sanitised to replace all
-non-alphanumeric characters with a dash to make it universally usable.
-
-=item B<--dtx-delay=>I<INT>
-
-Processing delay in milliseconds to handle discontinuous transmission (DTX) or
-other transmission gaps. Defaults to zero (disabled) and is applicable to
-transcoded audio streams only. When enabled, delays processing of received
-packets for the specified time (much like a jitter buffer) in order to trigger
-DTX handling when a transmission gap occurs. The decoder is then instructed to
-fill in the missing time during a transmission gap, for example by generating
-comfort noise. The delay should be configured to be higher than the expected
-incoming jitter.
-
-=item B<--max-dtx=>I<INT>
-
-Maximum duration for DTX handling in seconds. If no further RTP media is
-received within this time frame, then DTX processing will stop. Can be set to
-zero or negative to disable and keep DTX processing on indefinitely. Defaults
-to 30 seconds.
-
-=item B<--dtx-buffer=>I<INT>
-
-=item B<--dtx-lag=>I<INT>
-
-These two options together control the maximum number of packets and amount of
-audio that is allowed to be held in the DTX buffer. The B<dtx-buffer> option
-limits the number of packets held in the DTX buffer, while the B<dtx-lag>
-option limits the amount of audio (in milliseconds) to be held in the DTX
-buffer. A DTX buffer overflow is declared when both limits are exceeded, in
-which case DTX processing is sped up by B<dtx-shift> milliseconds.
-
-The defaults are 10 packets and 100 milliseconds.
-
-=item B<--dtx-shift=>I<INT>
-
-Amount of time in milliseconds that DTX processing is shifted forward (sped up)
-or backwards (delayed) in case of a DTX buffer overflow or underflow. An
-underflow occurs when RTP packets are received slower than expected, while an
-overflow occurs when packets are received faster than expected.
-
-If this value is set to zero then no adjustments of the DTX timer will be made.
-Instead, in order to keep up with the flow of received RTP packets, packets
-will be dropped or additional DTX audio will be generated as needed.
-
-=item B<--dtx-cn-params=>I<INT>
-
-Specify one comfort noise parameter. This option follows the same format as
-B<cn-payload> described below.
-
-This option is applicable to audio generated to fill in transmission gaps
-during a DTX event. The default setting is no value, which means silence will
-be generated to fill in DTX gaps.
-
-If any CN parameters are configured, the parameters will be passed to an RFC
-3389 CN decoder, and the generated comfort noise will be used to fill in DTX
-gaps.
-
-=item B<--amr-dtx=>B<native>|B<CN>
-
-Select the DTX behaviour for AMR codecs. The default is use the codec's
-internal processing: during a DTX event, a "no data" frame is passed to the
-decoder and the output is used as audio data.
-
-If B<CN> is selected here, the same DTX mechanism as other codecs use is used
-for AMR, which is to fill in DTX gaps with either silence or RFC 3389 comfort
-noise (see B<dtx-cn-params>). This also affects processing of received SID
-frames: SID frames would not be passed to the codec but instead be replaced by
-generated silence or comfort noise.
-
-=item B<--silence-detect=>I<FLOAT>
-
-Enable silence detection and specify threshold in percent. This option is
-applicable to transcoded stream only and defaults to zero (disabled).
-
-When enabled, silence detection will be performed on all transcoded audio
-streams. The threshold specified here is the sensitivity for detecting silence:
-higher thresholds result in more audio to be detected as silence, while lower
-thresholds result in less audio to be detected as silence. The threshold is
-specified as percent between zero and 100. If set to 100, then all audio would
-be detected as silence; if set to 50, then any audio that is quieter than 50%
-of the maximum volume would be detected as silence; and so on. Setting it to
-zero disables silence detection. To only detect silence that is very near or
-equal to absolute silence, set this value to a low number such as 0.01. (For
-certain codecs such as PCMA, a higher minimum threshold is required to detect
-complete silence, as their compressed payloads don't decode to actual silence
-but instead have a residual DC offset. For PCMA the minimum value is 0.013.)
-
-Audio that is detected as silence will be replaced by comfort noise as
-specified by the B<cn-payload> option (see below). Currently this is applicable
-only to RTP peers that have advertised support for the B<CN> RTP payload type,
-in which case the silence audio frames will be replaced by B<CN> RTP frames.
-
-=item B<--cn-payload=>I<INT>
-
-Specify one comfort noise parameter. This option can be given multiple times
-and the format follows RFC 3389. When specified at the command line, list the
-B<--cn-payload=> option multiple times, each one specifying a single CN
-parameter. When used in the config file, list the option only a single time and
-list multiple CN parameters separated by semicolons (e.g.
-I<cn-payload = 20;40;60>).
-
-The first CN payload value given is the noise level, specified as -dBov as per
-RFC 3389. This means that a noise level of zero corresponds to maximum volume,
-while higher numbers correspond to lower volumes. The highest allowable number
-is 127, corresponding to -127 dBov, which is near silence.
-
-Subsequent CN payload values carry spectral information (reflection
-coefficients) as per RFC 3389. Allowable values for each coefficient are
-between 0 and 254. Specifying spectral information is optional and the number
-of coefficients listed (model order) is variable.
-
-This option is applicable only to B<CN> packets generated from the silence
-detection mechanism described above. The configured CN parameters are used
-directly as payload of B<CN> packets sent by B<rtpengine>.
-
-The default values are 32 (-32 dBov) for the noise level and no spectral
-information.
-
-=item B<--player-cache>
-
-Enable caching of encoded media packets for media player. This is applicable
-for media playback initiated through the I<play media> command. When enabled
-B<rtpengine> will not simply decode given media files and then encode the media
-to RTP on demand and on the fly, but will rather decode and encode each media
-file in full the first time playback is requested, and then cache the resulting
-RTP packets in memory. This is done once for each media file and for each
-output RTP codec requested.
-
-Caching is done based on unique file name (with no consideration given to
-different file names that may point to the same file), or integer index for
-media files played from database. No verification of changing content of files
-or database entries is done. Media files provided as binary I<blob> are also
-cached, although in this case a hash over the entire media file must be
-performed, therefore this usage is not recommended.
-
-It's not possible to choose a different I<start-pos> for playback with this
-option enabled.
-
-RTP data is cached and retained in memory for the lifetime of the process.
-
-=item B<audio-buffer-length=>I<INT>
-
-Set the buffer length used by the audio player (see below) in milliseconds. The
-default is 500 milliseconds.
-
-The buffer must be long enough to accommodate at least two frames of audio from
-all contributing sources, which means at least 40 ms or 60 ms for most cases.
-If media playback (via the B<play media>) command is desired, then the buffer
-must be able to accommodate at least one full frame from the source media file,
-whose length can vary depending on the format of the source media file. For 8
-kHz B<.wav> files this is 256 ms (2048 samples). Therefore 500 ms is the
-recommended value.
-
-=item B<audio-buffer-delay=>I<INT>
-
-Initial delay for new sources contributing to an audio buffer (used by the
-audio player, see below) in milliseconds. The default is 5 ms.
-
-The initial delay is meant to compensate for varying inter-arrival times of
-media packets (jitter). If set too low, intermittent high jitter will result in
-gaps in the output audio. If set too high, output audio will have an
-unnecessary latency added to it.
-
-=item B<audio-player=>B<on-demand>|B<play-media>|B<transcoding>|B<always>
-
-Define when to enable the audio player if not explicitly instructed otherwise.
-The default setting is B<on-demand>.
-
-Enabling the audio player for a party to a call makes B<rtpengine> produce its
-own audio RTP stream (instead of just forwarding an audio stream received from
-elsewhere). The audio is generated from a circular audio buffer (see above) and
-all contributing audio sources are mixed into that one audio buffer.
-Contributing audio sources are audio streams received from elsewhere (that
-would otherwise simply be forwarded) and audio produced by the B<play media>
-command.
-
-With this set to B<on-demand>, the audio player is enabled only if explicitly
-requested by the user for a particular call via the B<audio-player=> option
-used in a signalling message.
-
-When set to B<play-media>, the audio player is enabled only while media
-playback via the B<play media> command is active. After media playback is
-finished, the audio player is again disabled and audio goes back to simply
-being forwarded.
-
-Setting this option to B<transcoding> leaves the audio player disabled unless
-any sort of transcoding is required for a call.
-
-With a setting of B<always>, the audio player is enabled for all calls, unless
-explicitly disabled via the B<audio-player=> option used in a signalling
-message. This forces all audio through the transcoding engine, even if input
-and output codecs are the same.
-
-Audio player usage can be changed on a call-by-call basis by including the
-B<audio-player=> option in a signalling message. This option supports the
-values B<transcoding> and B<always>, which result in the behaviour described
-just above, and B<off> which forces the audio player to be disabled regardless
-of this setting.
-
-=item B<--poller-per-thread>
-
-Enable 'poller per thread' functionality: for every worker thread (see the
---num-threads option) a poller will be created. With this option on, it is
-guaranteed that only a single thread will ever read from a particular socket,
-thus maintaining the order of the packets. Might help when having issues with
-DTMF packets (RFC 2833).
-
-=item B<--dtls-cert-cipher=>B<prime256v1>|B<RSA>
-
-Choose the type of key to use for the signature used by the self-signed
-certificate used for DTLS. The previous default was B<RSA>. The current default
-and the only other option is B<prime256v1> which is a 256-bit elliptic-curve
-key.
-
-=item B<--dtls-signature=>B<SHA-256>|B<SHA-1>
-
-Choose the hash algorithm to use for the signature used by the self-signed
-certificate used for DTLS. The default is B<SHA-256>. Not to be confused with
-the hash algorithm used for the certificate fingerprint inserted into the SDP
-(B<a=fingerprint:>), which is independent of the certificate's signature and
-can be selected during runtime.
-
-=item B<--dtls-rsa-key-size=>I<INT>
-
-Size in bits of the RSA key used by the DTLS certificate, if RSA is in use.
-Default is 2048 bits.
-
-=item B<--dtls-ciphers=>I<STRING>
-
-Ciphers allowed during the DTLS key exchange (not to be confused with the
-cipher used by the DTLS certificate). The format of this string is an OpenSSL
-cipher list. The default is
-B<DEFAULT:!NULL:!aNULL:!SHA256:!SHA384:!aECDH:!AESGCM+AES256:!aPSK>
-
-=item B<--dtls-mtu=>I<INT>
-
-Set DTLS MTU to enable fragmenting of large DTLS packets. Defaults to 1200.
-Minimum value is 576 as the internet protocol requires that hosts must be able to 
-process IP datagrams of at least 576 bytes (for IPv4) or 1280 bytes (for IPv6).
-This does not preclude link layers with an MTU smaller than this minimum MTU from 
-conveying IP data. Internet IPv4 path MTU is 68 bytes.
-
-=item B<--mqtt-host=>I<HOST>|I<IP>
-
-Host or IP address of the Mosquitto broker to connect to. Must be set to enable
-exporting stats to Mosquitto.
-
-=item B<--mqtt-port=>I<INT>
-
-Port of the Mosquitto broker. Defaults to 1883.
-
-=item B<--mqtt-id=>I<STRING>
-
-Client ID to use for Mosquitto. Default is a generated random string.
-
-=item B<--mqtt-keepalive=>I<INT>
-
-Keepalive interval in seconds. Defaults to 30.
-
-=item B<--mqtt-user=>I<USERNAME>
-
-=item B<--mqtt-pass=>I<PASSWORD>
-
-Credentials to connect to Mosquitto broker. At least a username must be given
-to enable authentication.
-
-=item B<--mqtt-cafile=>I<FILE>
-
-=item B<--mqtt-capath=>I<PATH>
-
-=item B<--mqtt-certfile=>I<FILE>
-
-=item B<--mqtt-keyfile=>I<FILE>
-
-=item B<--mqtt-tls-alpn=>I<STRING>
-
-Enable TLS to connect to Mosquitto broker, optionally with client certificate
-authentication. At least B<cafile> or B<capath> must be given to enable TLS. To
-enable client certificate authentication, both B<certfile> and B<keyfile> must
-be set. All files must be in PEM format. Password-proteted files are not
-supported. The B<tls-alpn> can be set (e.g. mqtt) if a service like AWS IoT
-Core shares the same TLS port for two different network protocols.
-
-=item B<--mqtt-publish-qos=>B<0>|B<1>|B<2>
-
-QoS value to use for publishing to Mosquitto. See Mosquitto docs for details.
-
-=item B<--mqtt-publish-topic=>I<STRING>
-
-Topic string to use for publishing to Mosquitto. Must be set to a non-empty
-string.
-
-=item B<--mqtt-publish-interval=>I<MILLISECONDS>
-
-Interval in milliseconds to publish to Mosquitto. Defaults to 5000 (5 seconds).
-
-=item B<--mqtt-publish-scope=>B<global>|B<summary>|B<call>|B<media>
-
-When set to B<summary>, one message will be published to Mosquitto every
-I<interval> milliseconds containing all global stats. A setting of B<global>
-has the same effect as B<summary> but will also contain a list of all running
-calls with stats for each call. When set to B<call>, one message per call will
-be published to Mosquitto with stats for that call every I<interval>
-milliseconds, plus one message every I<interval> milliseconds with global
-stats. When set to B<media>, one message per call media (usually one media per
-call participant, so usually 2 media per call) will be published to Mosquitto
-with stats for that call media every I<interval> milliseconds, plus one message
-every I<interval> milliseconds with global stats.
-
-=item B<--mos=>B<CQ>|B<LQ>
-
-MOS (Mean Opinion Score) calculation formula. Defaults to B<CQ> (conversational
-quality) which takes RTT into account and therefore requires peers to correctly
-send RTCP. If set to B<LQ> (listening quality) RTT is ignored, allowing a MOS to
-be calculated in the absence of RTCP.
-
-=item B<--measure-rtp>
-
-Enable measuring RTP metrics even for plain RTP passthrough scenarios. Without
-that option, RTP metrics are measured only in transcoding scenarios.
-
-=item B<--socket-cpu-affinity=>I<INT>
-
-Enables setting the socket CPU affinity via the B<SO_INCOMING_CPU> socket
-option if available. The default value is zero which disables this feature. If
-set to a positive number then the CPU affinity for all sockets belonging to the
-same call will be set to the same value. The number specifies the upper limit
-of the affinity to be set, and values will be used in a round-robin fashion
-(e.g. if set to B<8> then the values B<0> through B<7> will be used to set the
-affinity). If this option is set to a negative number, then the number of
-available CPU cores will be used.
-
-=back
-
-=head1 INTERFACES
-
-The command-line options B<-i> or B<--interface>, or equivalently the
-B<interface> config file option, specify local network interfaces for RTP.
-At least one must be given, but multiple can be specified.
-The format of the value is [I<NAME>B</>]I<IP>[!I<IP>] with I<IP> being
-either an IPv4 address, an IPv6 address, the name of a system network interface
-(such as I<eth0>), a DNS host name (such as I<test.example.com>), or B<any>.
-
-The possibility of configuring a network interface by name rather than
-by address should not be confused with the logical interface name used
-internally by B<rtpengine> (as described below).
-The I<NAME> token in the syntax above refers to the internal logical
-interface name, while the name of a system network interface is used
-in place of the first I<IP> token in the syntax above.
-For example, to configure a logical network interface called I<int>
-using all the addresses from the existing system network interface
-I<eth0>, you would use the syntax I<int/eth0>.
-(Unless omitted, the second I<IP> token used for the advertised address
-must be an actual network address and cannot be an interface name.)
-
-If DNS host names are used instead of addresses or interface names, the lookup
-will be done only once during daemon start-up.
-
-The special keyword B<any> can be used to listen on any and all available local
-interface addresses except from loopback devices. This keyword should only be
-given once in place of a more explicit interface configuration.
-
-To configure multiple interfaces using the command-line options,
-simply present multiple B<-i> or B<--interface> options.
-When using the config file, only use a single B<interface> line,
-but specify multiple values separated by semicolons (e.g.
-I<interface = internal/12.23.34.45;external/23.34.45.54>).
-
-If an interface option is given using a system interface name in place
-of a network address, and if multiple network address are found
-configured on that network interface, then B<rtpengine> behaves as
-if multiple B<--interface> options had been specified.
-For example, if interface I<eth0> exists with both addresses
-I<192.168.1.120> and I<2001:db8:85a3::7334> configured on it, and if
-the option I<--interface=ext/eth0> is given, then B<rtpengine> would
-behave as if both options I<--interface=ext/192.168.1.120> and
-I<--interface=ext/2001:db8:85a3::7334> had been specified.
-
-The second IP address after the exclamation point is optional and can
-be used if the address to advertise in outgoing SDP bodies should be
-different from the actual local address.
-This can be useful in certain cases, such as your SIP proxy being behind NAT.
-For example, I<--interface=10.65.76.2!192.0.2.4> means that I<10.65.76.2>
-is the actual local address on the server, but outgoing SDP bodies should
-advertise I<192.0.2.4> as the address that endpoints should talk to.
-Note that you may have to escape the exclamation point from your shell
-when using command-line options, e.g. using I<\!>.
-
-Giving an interface a name (separated from the address by a slash) is
-optional; if omitted, the name B<default> is used.
-Names are useful to create logical interfaces which consist of one or
-more local addresses.
-It is then possible to instruct B<rtpengine> to use particular interfaces
-when processing an SDP message, to use different local addresses when
-talking to different endpoints.
-The most common use case for this is to bridge between one or more
-private IP networks and the public internet.
-
-For example, if clients coming from a private IP network must communicate
-their RTP with the local address I<10.35.2.75>, while clients coming from
-the public internet must communicate with your other local address
-I<192.0.2.67>, you could create one logical interface I<pub> and a second
-one I<priv> by using I<--interface=pub/192.0.2.67 --interface=priv/10.35.2.75>.
-You can then use the B<direction> option to tell B<rtpengine> which local
-address to use for which endpoints (either I<pub> or I<priv>).
-
-If multiple logical interfaces are configured, but the B<direction>
-option is not given in a particular call, then the first interface
-given on the command line will be used.
-
-It is possible to specify multiple addresses for the same logical
-interface (the same name).
-Most commonly this would be one IPv4 addrsess and one IPv6 address,
-for example: I<--interface=192.168.63.1 --interface=fe80::800:27ff:fe00:0>.
-In this example, no interface name is given, therefore both addresses
-will be added to a logical interface named B<default>.
-You would use the B<address family> option to tell B<rtpengine> which
-address to use in a particular case.
-
-It is also possible to have multiple addresses of the same family in a
-logical network interface.
-In this case, the first address (of a particular family) given for an
-interface will be the primary address used by B<rtpengine> for most
-purposes.
-Any additional addresses will be advertised as additional ICE candidates
-with increasingly lower priority.
-This is useful on multi-homed systems and allows endpoints to choose the
-best possible path to reach the RTP proxy.
-If ICE is not being used, then additional addresses will go unused,
-even though ports would still get allocated on those interfaces.
-
-Another option is to give interface names in the format I<BASE:SUFFIX>.
-This allows interfaces to be used in a round-robin fashion, useful
-for load-balancing the port ranges of multiple interfaces.
-For example, consider the following configuration:
-I<--interface=pub:1/192.0.2.67 --interface=pub:2/10.35.2.75>.
-These two interfaces can still be referenced directly by name (e.g.
-I<direction=pub:1>), but it is now also possible to reference only
-the base name (i.e. I<direction=pub>).
-If the base name is used, one of the two interfaces is selected in a
-round-robin fashion, and only if the interface actually has enough
-open ports available.
-This makes it possible to effectively increase the number of available
-media ports across multiple IP addresses.
-There is no limit on how many interfaces can share the same base name.
-
-It is possible to combine the I<BASE:SUFFIX> notation with specifying
-multiple addresses for the same interface name.
-An advanced example could be (using config file notation, and omitting
-actual network addresses):
-
-  interface = pub:1/IPv4 pub:1/IPv4 pub:1/IPv6 pub:2/IPv4 pub:2/IPv6 pub:3/IPv6 pub:4/IPv4
-
-In this example, when I<direction=pub> is IPv4 is needed as a primary
-address, either I<pub:1>, I<pub:2>, or I<pub:4> might be selected.
-When I<pub:1> is selected, one IPv4 and one IPv6 address will be used
-as additional ICE alternatives.
-For I<pub:2>, only one IPv6 is used as ICE alternative, and for I<pub:4>
-no alternatives would be used.
-When IPv6 is needed as a primary address, either I<pub:1>, I<pub:2>, or
-I<pub:3> might be selected.
-If at any given time not enough ports are available on any interface,
-it will not be selected by the round-robin algorithm.
-
-It is possible to use the round-robin algorithm even if the B<direction>
-is not given.
-If the first given interface has the I<BASE:SUFFIX> format then the
-round-robin algorithm is used and will select interfaces with the
-same I<BASE> name.
-
-If you are not using the NG protocol but rather the legacy UDP protocol
-used by the B<rtpproxy> module, the interfaces must be named B<internal>
-and B<external> corresponding to the B<i> and B<e> flags if you wish to
-use network bridging in this mode.
-
-=head1 EXIT STATUS
-
-=over
-
-=item B<0>
-
-Successful termination.
-
-=item B<1>
-
-An error occurred.
-
-=back
-
-=head1 ENVIRONMENT
-
-=over
-
-=item B<RTPENGINE_REDIS_AUTH_PW>
-
-Redis server password for persistent state storage.
-
-=item B<RTPENGINE_REDIS_WRITE_AUTH_PW>
-
-Redis server password for write operations, if B<--redis> has been
-specified, in which case the one specified in B<--redis> will be used for
-read operations only.
-
-=back
-
-=head1 FILES
-
-=over
-
-=item F</etc/rtpengine/rtpengine.conf>
-
-Configuration file.
-
-=back
-
-=head1 EXAMPLES
-
-A typical command line (enabling both UDP and NG protocols) may look like:
-
-  rtpengine --table=0 --interface=10.64.73.31 --interface=2001:db8::4f3:3d \
-    --listen-udp=127.0.0.1:22222 --listen-ng=127.0.0.1:2223 --tos=184 \
-    --pidfile=/run/rtpengine.pid
-
-=head1 SEE ALSO
-
-L<kamailio(8)>.
diff --git a/daemon/rtpengine.pod b/daemon/rtpengine.pod
new file mode 120000
index 000000000..2c53748da
--- /dev/null
+++ b/daemon/rtpengine.pod
@@ -0,0 +1 @@
+../docs/rtpengine.pod
\ No newline at end of file
diff --git a/docs/rtpengine.pod b/docs/rtpengine.pod
new file mode 100644
index 000000000..5dc098fb0
--- /dev/null
+++ b/docs/rtpengine.pod
@@ -0,0 +1,1365 @@
+=head1 NAME
+
+rtpengine - NGCP proxy for RTP and other UDP based media traffic
+
+=head1 SYNOPSIS
+
+B<rtpengine> B<--interface>=I<addr>... B<--listen-tcp>|B<--listen-udp>|B<--listen-ng>|B<--listen-tcp-ng>|B<--listen-http>|B<--listen-https>=I<addr>... [I<option>...]
+
+=head1 DESCRIPTION
+
+The Sipwise NGCP rtpengine is a proxy for RTP traffic and other UDP based
+media traffic.
+It is meant to be used with the Kamailio SIP proxy and forms a drop-in
+replacement for any of the other available RTP and media proxies.
+
+=head1 OPTIONS
+
+Most of these options are indeed optional, with two exceptions. It's
+mandatory to specify at least one local IP address through B<--interface>,
+and at least one of the B<--listen->I<...> options must be given.
+
+All options can (and should) be provided in a config file instead of
+at the command line. See the B<--config-file> option below for details.
+
+=over 4
+
+=item B<--help>
+
+Print the usage information.
+
+=item B<-v>, B<--version>
+
+If called with this option, the B<rtpengine> daemon will simply print its
+version number and exit.
+
+=item B<--codecs>
+
+Print a list of supported codecs and exit.
+
+=item B<--config-file=>I<FILE>
+
+Specifies the location of a config file to be used. The config file is an
+I<.ini> style config file, with all command-line options listed here also
+being valid options in the config file.
+For all command-line options, the long name version instead of the
+single-character version (e.g. B<table> instead of just B<t>) must be
+used in the config file.
+For boolean options that are either present or not (e.g. B<no-fallback>), a
+boolean value (either B<true> or B<false>) must be used in the config file.
+If an option is given in both the config file and at the command line,
+the command-line value overrides the value from the config file.
+Options that can be specified multiple times on the command line must be
+given only once in the config file, with the multiple values separated by
+semicolons (see section L<INTERFACES> below for an example).
+
+As a special value, B<none> can be passed here to suppress loading of the
+default config file F</etc/rtpengine/rtpengine.conf>.
+
+=item B<--config-section=>I<STRING>
+
+Specifies the I<.ini> style section to be used in the config file.
+Multiple sections can be present in the config file, but only one can be
+used at a time.
+The default value is B<rtpengine>.
+A config file section is started in the config file using square brackets
+(e.g. B<[rtpengine]>).
+
+=item B<-t>, B<--table=>I<INT>
+
+Takes an integer argument and specifies which kernel table to use for
+in-kernel packet forwarding.
+See the section on in-kernel operation in the F<README.md> for more detail.
+Optional and defaults to zero.
+If in-kernel operation is not desired, a negative number can be specified.
+
+=item B<-F>, B<--no-fallback>
+
+Will prevent fallback to userspace-only operation if the kernel module is
+unavailable.
+In this case, startup of the daemon will fail with an error if this option
+is given.
+
+=item B<-S>, B<--save-interface-ports>
+
+Will bind ports only on the first available local interface, of desired
+family, of logical interface. If no ports available on any local interface
+of desired family, give an error message.
+
+In this case, ICE will be broken.
+
+=item B<-i>, B<--interface=>[I<NAME>B</>]I<IP>[B<!>I<IP>]
+
+Specifies a local network interface for RTP.
+At least one must be given, but multiple can be specified.
+See the section L<INTERFACES> just below for details.
+
+=item B<-l>, B<--listen-tcp=>[I<IP>B<:>]I<PORT>
+
+=item B<-u>, B<--listen-udp=>[I<IP46>B<:>]I<PORT>
+
+=item B<-n>, B<--listen-ng=>[I<IP46>B<:>]I<PORT>
+
+=item B<-n>, B<--listen-tcp-ng=>[I<IP46>B<:>]I<PORT>
+
+These options each enable one of the 4 available control protocols if given
+and each take either just a port number as argument, or an I<address:port>
+pair, separated by colon.
+At least one of these 3 options must be given.
+
+The B<tcp> protocol is obsolete.
+It was used by old versions of B<OpenSER> and its B<mediaproxy> module.
+It is provided for backwards compatibility.
+
+The B<udp> protocol is used by B<Kamailio>'s B<rtpproxy> module.
+In this mode, B<rtpengine> can be used as a drop-in replacement for any
+other compatible RTP proxy.
+
+The B<ng> protocol is an advanced control protocol and can be used with
+B<Kamailio>'s B<rtpengine> module.
+With this protocol, the complete SDP body is passed to B<rtpengine>,
+rewritten and passed back to B<Kamailio>.
+Several additional features are available with this protocol, such as
+ICE handling, SRTP bridging, etc.
+
+The B<tcp-ng> protocol is in fact the B<ng> protocol but transported over TCP.
+
+It is recommended to specify not only a local port number, but also
+B<127.0.0.1> as interface to bind to.
+
+=item B<-c>, B<--listen-cli=>[I<IP46>:]I<PORT>
+
+TCP ip and port to listen for the CLI (command line interface).
+
+=item B<-g>, B<--graphite=>I<IP46>:I<PORT>
+
+Address of the graphite statistics server.
+
+=item B<-w>, B<--graphite-interval=>I<INT>
+
+Interval of the time when information is sent to the graphite server.
+
+=item B<--graphite-prefix=>I<STRING>
+
+Add a prefix for every graphite line.
+
+=item B<--graphite-timeout=>I<INT>
+
+Sets after how much time (seconds) to force fail graphite socket connection,
+when graphite server is filtered out. If set to 0, there are no changes.
+
+=item B<-t>, B<--tos=>I<INT>
+
+Takes an integer as argument and if given, specifies the TOS value that
+should be set in outgoing packets.
+The default is to leave the TOS field untouched.
+A typical value is 184 (B<Expedited Forwarding>).
+
+=item B<--control-tos=>I<INT>
+
+Takes an integer as argument and if given, specifies the TOS value that
+should be set in the control-ng interface packets.
+The default is to leave the TOS field untouched.
+This parameter can also be set or listed via B<rtpengine-ctl>.
+
+=item B<--control-pmtu=>B<want>|B<dont>
+
+Forces a specific PMTU discovery behaviour on IPv4 UDP control sockets,
+overriding the system-wide default. If set to B<want> then path MTU discovery
+is performed, initially enabling the DF (don't fragment) bit on outgoing IPv4
+packets until the path MTU has been discovered through reception of a
+"fragmentation needed" ICMP packet. If set to B<dont> then path MTU discovery
+is disabled, leaving the DF bit unset, and relying on the routers within the
+network path to perform any necessary fragmentation.
+
+The setting of B<dont> is useful in broken IPv4 environments without
+functioning PMTU discovery, for example in networks which unconditionally block
+all ICMP.
+
+=item B<-o>, B<--timeout=>I<SECS>
+
+Takes the number of seconds as argument after which a media stream should
+be considered dead if no media traffic has been received.
+If all media streams belonging to a particular call go dead, then the call
+is removed from B<rtpengine>'s internal state table.
+Defaults to 60 seconds.
+
+=item B<-s>, B<--silent-timeout=>I<SECS>
+
+Ditto as the B<--timeout> option, but applies to muted or inactive media
+streams.
+Defaults to 3600 (one hour).
+
+=item B<-a>, B<--final-timeout=>I<SECS>
+
+The number of seconds since call creation, after call is deleted.
+Useful for limiting the lifetime of a call.
+This feature can be disabled by setting the parameter to 0.
+By default this timeout is disabled.
+
+=item B<--offer-timeout=>I<SECS>
+
+This timeout (in seconds) is applied to calls which only had an B<offer>
+but no B<answer>.
+Defaults to 3600 (one hour).
+
+=item B<-p>, B<--pidfile=>I<FILE>
+
+Specifies a path and file name to write the daemon's PID number to.
+
+=item B<-f>, B<--foreground>
+
+If given, prevents the daemon from daemonizing, meaning it will stay in
+the foreground.
+Useful for debugging.
+
+=item B<-m>, B<--port-min=>I<INT>
+
+=item B<-M>, B<--port-max=>I<INT>
+
+Both take an integer as argument and together define the local port range
+from which B<rtpengine> will allocate UDP ports for media traffic relay.
+Default to 30000 and 40000 respectively.
+
+=item B<-L>, B<--log-level=>I<INT>
+
+Takes an integer as argument and controls the highest log level which will be
+sent to syslog. This is merely the default log level used for logging
+subsystems (see below) that don't explicitly have a separate log level
+configured.
+
+The log levels correspond to the ones found in the L<syslog(3)> man page.
+The default value is B<6>, equivalent to LOG_INFO.
+The highest possible value is B<7> (LOG_DEBUG) which will log everything.
+
+During runtime, the log level can be decreased by sending the signal
+SIGURS1 to the daemon and can be increased with the signal SIGUSR2.
+
+=item B<--log-level->I<subsystem>B<=>I<INT>
+
+Configures a log level for one of the logging subsystems. A logging subsystem
+which doesn't have a log level configured explicitly takes its default value
+from the B<log-level> setting described above, with the exception of the
+B<internals> subsystem which by default has all logging disabled.
+
+The full list of logging subsystems can be viewed by pulling up the B<--help>
+online help. Some (if not all) subsystems are: B<core>, B<spandsp> (messages
+generated by SpanDSP itself), B<ffmpeg> (messages generated by ffmpeg libraries
+themselves), B<transcoding> (messages related to RTP/media transcoding),
+B<codec> (messages related to codec negotiation), B<rtcp>, B<ice>, B<crypto>
+(messages related to crypto/SRTP/SDES/DTLS negotiation), B<srtp> (messages
+related to RTP/SRTP en/decryption), B<internals> (disabled by default), B<http>
+(includes WebSocket), B<control> (messages related to control protocols,
+including SDP exchanges), B<dtx>.
+
+=item B<--log-facilty=>B<daemon>|B<local0>|...|B<local7>|...
+
+The syslog facilty to use when sending log messages to the syslog daemon.
+Defaults to B<daemon>.
+
+=item B<--log-facilty-cdr=>B<daemon>|B<local0>|...|B<local7>|...
+
+Same as B<--log-facility> with the difference that only CDRs are written
+to this log facility.
+
+=item B<--log-facilty-rtcp=>B<daemon>|B<local0>|...|B<local7>|...
+
+Same as B<--log-facility> with the difference that only RTCP data is
+written to this log facility.
+Be careful with this parameter since there may be a lot of information
+written to it.
+
+=item B<--log-facilty-dtmf=>B<daemon>|B<local0>|...|B<local7>|...
+
+Same as B<--log-facility> with the difference that only DTMF events are
+written to this log facility.
+DTMF events are extracted from RTP packets conforming to RFC 4733, are
+encoded in JSON format, and written as soon as the end of an event is
+detected.
+
+=item B<--log-format=>B<default>|B<parsable>
+
+Selects between multiple log output styles.
+The default is to prefix log lines with a description of the relevant
+entity, such as B<[CALLID]> or B<[CALLID port 12345]>.
+The B<parsable> output style is similar, but makes the ID easier to
+parse by enclosing it in quotes, such as B<[ID="CALLID"]>
+or B<[ID="CALLID" port="12345"]>.
+
+=item B<--dtmf-log-dest=>I<IP46>:I<PORT>
+
+Configures a target address for logging detected DTMF event. Similar
+to the feature enabled by B<--log-facilty-dtmf>, but instead of writing
+detected DTMF events to syslog, this sends the JSON payload to the
+given address as UDP packets.
+
+=item B<--dtmf-log-ng-tcp>
+
+If B<--listen-tcp-ng> is enabled, this will send DTMF events to all
+connected clients encoded in bencode format.
+
+=item B<--dtmf-no-log-injects>
+If B<--dtmf-no-log-injects> is enabled, DTMF events resulting from a
+call to inject-DTMF won't be sent to B<--dtmf-log-dest=> or B<--listen-tcp-ng>
+
+=item B<--dtmf-no-suppress>
+
+Some RTP clients continue to send audio RTP packets during a DTMF event,
+resulting in both audio packets and DTMF packets appearing simultaneously. By
+default, when transcoding, B<rtpengine> suppresses audio packets during a DTMF
+event and will only send DTMF packets until the DTMF event is over. Setting
+this option disables this feature.
+
+=item B<--log-srtp-keys>
+
+Write SRTP keys to error log instead of debug log.
+
+=item B<-E>, B<--log-stderr>
+
+Log to stderr instead of syslog.
+Only useful in combination with B<--foreground>.
+
+=item B<--split-logs>
+
+Split multi-line log messages into individual log messages so that each
+line receives its own log line prefix.
+
+=item B<--max-log-line-length=>I<INT>
+
+Split log lines into multiple lines when they exceed the character count given
+here. Can be set to a negative value to allow unlimited length log lines. Set
+to zero for the default value, which is unlimited if logging to stderr, or 500
+if logging to syslog.
+
+=item B<--no-log-timestamps>
+
+Don't add timestamps to log lines written to stderr.
+Only useful in combination with B<--log-stderr>.
+
+=item B<--log-name=>I<STRING>
+
+Set the id to be printed in syslog.
+Defaults to B<rtpengine>.
+
+=item B<--log-mark-prefix=>I<STRING>
+
+Prefix to be added to particular data fields in log files that are deemed
+sensitive and/or private information. Defaults to an empty string.
+
+=item B<--log-mark-suffix=>I<STRING>
+
+Suffix to be added to particular data fields in log files that are deemed
+sensitive and/or private information. Defaults to an empty string.
+
+=item B<--num-threads=>I<INT>
+
+How many worker threads to create, must be at least one.
+The default is to create as many threads as there are CPU cores available.
+If the number of CPU cores cannot be determined or if it is less than four,
+then the default is four.
+
+=item B<--media-num-threads=>I<INT>
+
+Number of threads to launch for media playback. Defaults to the same
+number as B<num-threads>. This can be set to zero if no media playback
+functionality is desired.
+
+Media playback is actually handled by two threads: One for reading and
+decoding the media file, and another to schedule and send out RTP packets.
+So for example, if this option is set to 4, in total 8 threads will be
+launched.
+
+=item B<--thread-stack=>I<INT>
+
+Set the stack size of each thread to the value given in kB. Defaults to 2048
+kB. Can be set to -1 to leave the default provided by the OS unchanged.
+
+=item B<--evs-lib-path=>I<FILE>
+
+Points to the shared object file (B<.so>) containing the reference
+implementation for the EVS codec. See the F<README> for more details.
+
+=item B<--sip-source>
+
+The original B<rtpproxy> as well as older version of B<rtpengine> by default
+did not honour IP addresses given in the SDP body, and instead used the
+source address of the received SIP message as default endpoint address.
+Newer versions of B<rtpengine> reverse this behaviour and honour the
+addresses given in the SDP body by default. This option restores the
+old behaviour.
+
+=item B<--dtls-passive>
+
+Enables the B<DTLS=passive> flag for all calls unconditionally.
+
+=item B<-d>, B<--delete-delay=>I<INT>
+
+Delete the call after the specified delay from memory.
+Can be set to zero for immediate call deletion.
+
+=item B<-r>, B<--redis=>[I<PW>B<@>]I<IP>B<:>I<PORT>B</>I<INT>
+
+Connect to specified Redis database (with the given database number) and
+use it for persistence storage.
+The format of this option is I<ADDRESS>:I<PORT>/I<DBNUM>, for example
+I<127.0.0.1:6379/12> to connect to the Redis DB number 12 running on
+localhost on the default Redis port.
+
+If the Redis database is protected with an authentication password, the
+password can be supplied by prefixing the argument value with the password,
+separated by an B<@> symbol, for example I<foobar@127.0.0.1:6379/12>.
+Note that this leaves the password visible in the process list, posing a
+security risk if untrusted users access the same system.
+As an alternative, the password can also be supplied in the shell
+environment through the environment variable B<RTPENGINE_REDIS_AUTH_PW>.
+
+On startup, B<rtpengine> will read the contents of this database and
+restore all calls stored therein.
+During runtime operation, B<rtpengine> will continually update the
+database's contents to keep it current, so that in case of a service
+disruption, the last state can be restored upon a restart.
+
+When this option is given, B<rtpengine> will delay startup until the
+Redis database adopts the master role (but see below).
+
+=item B<-w>, B<--redis-write=>[I<PW>B<@>]I<IP>B<:>I<PORT>B</>I<INT>
+
+Configures a second Redis database for write operations.
+If this option is given in addition to the first one, then the first
+database will be used for read operations (i.e. to restore calls from)
+while the second one will be used for write operations (to update states
+in the database).
+
+For password protected Redis servers, the environment variable for the
+password is B<RTPENGINE_REDIS_WRITE_AUTH_PW>.
+
+When both options are given, B<rtpengine> will start and use the Redis
+database regardless of the database's role (master or slave).
+
+=item B<-k>, B<--subscribe-keyspace=>I<INT>
+
+List of redis keyspaces to subscribe.
+If this is not present, no keyspaces are subscribed (default behaviour).
+Further subscriptions could be added/removed via B<rtpengine-ctl ksadd/ksrm>.
+This may lead to enabling/disabling of the redis keyspace notification feature.
+
+=item B<--redis-num-threads=>I<INT>
+
+How many redis restore threads to create.
+The default is 4.
+
+=item B<--redis-expires=>I<INT>
+
+Expire time in seconds for redis keys.
+Default is 86400.
+
+=item B<--active-switchover>
+
+With this option enabled, any activity (such as signalling or media) on a call
+that was created through a Redis keyspace notification will make B<rtpengine>
+take control of that call. Without this option, an explicit command is required
+for B<rtpengine> to take (or relinquish) control of a call.
+
+=item B<-q>, B<--no-redis-required>
+
+When this parameter is present or B<NO_REDIS_REQUIRED='yes'> or B<'1'> in
+the config file, B<rtpengine> starts even if there is no initial connection
+to redis databases (either to B<-r> or to B<-w> or to both redis).
+
+Be aware that if the B<-r> redis cannot be initially connected, sessions
+are not reloaded upon rtpengine startup, even though rtpengine still starts.
+
+=item B<--redis-allowed-errors>
+
+If this parameter is present and has a value >= 0, it will configure how
+many consecutive errors are allowed when communicating with a redis server
+before the redis communication will be temporarily disabled for that server.
+While the communication is disabled there will be no attempts to reconnect
+to redis or send commands to that server.
+Default value is -1, meaning that this feature is disabled.
+This parameter can also be set or listed via B<rtpengine-ctl>.
+
+=item B<--redis-disable-time>
+
+This parameter configures the number of seconds redis communication is
+disabled because of errors.
+This works together with redis-allowed-errors parameter.
+The default value is 10.
+This parameter can also be set or listed via B<rtpengine-ctl>.
+
+=item B<--redis-cmd-timeout=>I<INT>
+
+If this parameter is set to a non-zero value it will set the timeout,
+in milliseconds, for each command to the redis server.
+If redis does not reply within the specified timeout the command will fail.
+The default value is 0, meaning that the commands will be blocking without
+timeout.
+This parameter can also be set or listed via B<rtpengine-ctl>; note that
+setting the parameter to 0 will require a reconnect on all configured
+redis servers.
+
+=item B<--redis-connect-timeout=>I<INT>
+
+This parameter sets the timeout value, in milliseconds, when connecting
+to a redis server.
+If the connection cannot be made within the specified timeout the
+connection will fail.
+Note that in case of failure, when reconnecting to redis, a B<PING> command
+is issued before attempting to connect so the B<--redis-cmd-timeout> value
+will also be added to the total waiting time.
+This is useful if using B<--redis-allowed-errors>, when attempting to
+estimate the total lost time in case of redis failures.
+The default value for the connection timeout is 1000ms.
+This parameter can also be set or listed via B<rtpengine-ctl>.
+
+=item B<-b>, B<--b2b-url=>I<STRING>
+
+Enables and sets the URI for an XMLRPC callback to be made when a call is
+torn down due to packet timeout.
+The special code B<%%> can be used in place of an IP address, in which case
+the source address of the originating request (or alternatively the address
+specified using the B<xmlrpc-callback> B<ng> protocol option) will be used.
+
+=item B<-x>, B<--xmlrpc-format=>I<INT>
+
+Selects the internal format of the XMLRPC callback message for B2BUA call
+teardown.
+0 is for SEMS,
+1 is for a generic format containing the call-ID only,
+2 is for Kamailio.
+
+=item B<--max-sessions=>I<INT>
+
+Limit the number of maximum concurrent sessions.
+Set at startup via B<max-sessions> in config file.
+Set at runtime via B<rtpengine-ctl> util.
+Setting the B<rtpengine-ctl set maxsessions 0> can be used in draining
+rtpengine sessions.
+Enable feature: B<max-sessions=1000>
+Enable feature: B<rtpengine-ctl set maxsessions> >= 0
+Disable feature: B<rtpengine-ctl set maxsessions -1>
+By default, the feature is disabled (i.e. maxsessions == -1).
+
+=item B<--max-load=>I<FLOAT>
+
+If the current 1-minute load average exceeds the value given here,
+reject new sessions until the load average drops below the threshold.
+
+=item B<--max-cpu=>I<FLOAT>
+
+If the current CPU usage (in percent) exceeds the value given here,
+reject new sessions until the CPU usage drops below the threshold.
+CPU usage is sampled in 0.5-second intervals.
+Only supported on systems providing a Linux-style F</proc/stat>.
+
+=item B<--max-bandwidth=>I<INT>
+
+If the current bandwidth usage (in bytes per second) exceeds the value
+given here, reject new sessions until the bandwidth usage drops below
+the threshold.
+Bandwidth usage is sampled in 1-second intervals and is based on
+received packets, not sent packets.
+
+=item B<--homer=>I<IP46>B<:>I<PORT>
+
+Enables sending the decoded contents of RTCP packets to a Homer SIP
+capture server.
+The transport is HEP version 3 and payload format is JSON.
+This argument takes an IP address and a port number as value.
+
+=item B<--homer-protocol=>B<udp>|B<tcp>
+
+Can be either B<udp> or B<tcp> with B<udp> being the default.
+
+=item B<--homer-id=>I<INT>
+
+The HEP protocol used by Homer contains a "capture ID" used to distinguish
+different sources of capture data.
+This ID can be specified using this argument.
+
+=item B<--recording-dir=>I<FILE>
+
+An optional argument to specify a path to a directory where PCAP recording
+files and recording metadata files should be stored. If not specified,
+support for call recording will be disabled.
+
+B<rtpengine> supports multiple mechanisms for recording calls.
+See B<recording-method> below for a list.
+The default recording method B<pcap> is described in this section.
+
+PCAP files will be stored within a F<pcap> subdirectory and metadata
+within a F<metadata> subdirectory.
+
+The format for a metadata file is (with a trailing newline):
+
+	/path/to/recording-pcap.pcap
+
+	SDP mode: offer
+	SDP before RTP packet: 1
+
+	first SDP
+
+	SDP mode: answer
+	SDP before RTP packet: 1
+
+	second SDP
+
+	...
+
+	SDP mode: answer
+	SDP before RTP packet: 100
+
+	n-th and final SDP
+
+
+	start timestamp (YYYY-MM-DDThh:mm:ss)
+	end timestamp   (YYYY-MM-DDThh:mm:ss)
+
+
+	generic metadata
+
+There are two empty lines between each logic block of metadata.
+We write out all answer SDP, each separated from one another by one empty
+line.
+The generic metadata at the end can be any length with any number of
+lines.
+Metadata files will appear in the subdirectory when the call completes.
+PCAP files will be written to the subdirectory as the call is being
+recorded.
+
+Since call recording via this method happens entirely in userspace,
+in-kernel packet forwarding cannot be used for calls that are currently
+being recorded and packet forwarding will thus be done in userspace only.
+
+=item B<--recording-method=>B<pcap>|B<proc>|B<all>
+
+Multiple methods of call recording are supported and this option can be
+used to select one.
+Currently supported are the method B<pcap>, B<proc> and B<all>.
+The default method is B<pcap> and is the one described above.
+
+The recording method B<proc> works by writing metadata files directly into
+the B<recording-dir> (i.e. not into a subdirectory) and instead of recording
+RTP packet data into pcap files, the packet data is exposed via a special
+interface in the F</proc> filesystem.
+Packets must then be retrieved from this interface by a dedicated userspace
+component (usually a daemon such as recording-daemon included in this
+repository).
+
+Packet data is held in kernel memory until retrieved by the userspace
+component, but only a limited number of packets (default 10) per media
+stream.
+If packets are not retrieved in time, they will be simply discarded.
+This makes it possible to flag all calls to be recorded and then leave it
+to the userspace component to decided whether to use the packet data for
+any purpose or not.
+
+In-kernel packet forwarding is fully supported with this recording method
+even for calls being recorded.
+
+The recording method B<all> will enable both B<pcap> and B<proc>
+at the same time.
+
+=item B<--recording-format=>B<raw>|B<eth>
+
+When recording to pcap file in B<raw> (default) format, there is no
+ethernet header.
+When set to B<eth>, a fake ethernet header is added, making each package
+14 bytes larger.
+
+=item B<--record-egress>
+
+Apply media recording to egress media streams (as they are sent by
+B<rtpengine>) instead of media streams as they are received. This makes it
+possible to include manipulated and generated media (such as from the B<play
+media> command) in the recordings.
+
+=item B<--iptables-chain=>I<STRING>
+
+This option enables explicit management of an iptables chain.
+When enabled, B<rtpengine> takes control of the given iptables chain,
+which must exist already prior to starting the daemon.
+Upon startup, B<rtpengine> will flush the chain, and then add one B<ACCEPT>
+rule for each media port (RTP/RTCP) opened.
+Each rule will exactly match the individual port and destination IP address,
+and will be created with the call ID as iptables comment.
+The rule will be deleted when the port is closed.
+
+This option allows creating a firewall with a default B<DROP> policy for
+the entire port range used by B<rtpengine> and then referencing the given
+iptables chain to only selectively allow the ports actually in use.
+
+Note that this applies only to media ports, and does not apply to any other
+ports (such as the control ports) used by B<rtpengine>.
+
+Also note that the iptables API is not the most efficient one around and
+does not lend itself to fast dynamic creation and deletion of rules.
+If you have a high call volume, and especially many call attempts per
+second, you might experience significant performance impact.
+This is not a shortcoming of B<rtpengine> but rather of iptables and its
+API implementation in the Linux kernel.
+In such a case, it is recommended to add a static iptables rule for the
+entire media port range instead, and not use this option.
+
+=item B<--scheduling=>B<default>|...
+
+=item B<--priority=>I<INT>
+
+=item B<--idle-scheduling=>B<default>|...
+
+=item B<--idle-priority=>I<INT>
+
+These options control various thread scheduling parameters.
+The B<scheduling> and B<priority> settings are applied to the main
+worker threads, while the B<idle-> versions of these settings are
+applied to various lower priority threads, such as timer runs.
+
+The B<scheduling> settings take the name of one of the supported
+scheduler policies.
+Setting it to B<default> or B<none> is equivalent to not setting the
+option at all and leaves the system default in place.
+The strings B<fifo> and B<rr> refer to realtime scheduling policies.
+B<other> is the Linux default scheduling policy.
+B<batch> is similar to B<other> except for a small wake-up scheduling
+penalty.
+B<idle> is an extremely low priority scheduling policy.
+The Linux-specific B<deadline> policy is not supported by B<rtpengine>.
+Not all systems necessarily supports all scheduling policies; refer to
+your system's sched(7) man page for details.
+
+The B<priority> settings correspond to the scheduling priority for
+realtime (B<fifo> or B<rr>) scheduling policies and must be in the range
+of 1 (low) through 99 (high).
+For all other scheduling policies (including no policy specified), the
+B<priority> settings correspond to the B<nice> value and should be in
+the range of -20 (high) through 19 (low).
+Not all systems support thread-specific B<nice> values; on such a system,
+using these settings might have unexpected results.
+(Linux does support thread-specific B<nice> values.)
+Refer to your system's sched(7) man page.
+
+=item B<--mysql-host=>I<HOST>|I<IP>
+
+=item B<--mysql-port=>I<INT>
+
+=item B<--mysql-user=>I<USERNAME>
+
+=item B<--mysql-pass=>I<PASSWORD>
+
+Configuration for playing back media files that are stored in a
+B<MySQL> (or B<MariaDB>) database. At least B<mysql-host> must be configured
+for this to work. The others are optional and default to their respective
+values from the B<MySQL>/B<MariaDB> client library.
+
+=item B<--mysql-query=>I<STRING>
+
+Query to be used for retrieving media files from the database. No default
+exist, therefore this is a mandatory configuration for media playback from
+database. The provided query string must contain the single format placeholder
+B<%llu> and must not contain any other format placeholders. The ID value
+passed to B<rtpengine> in the B<db-id> key of the B<play media> message will
+be used in place of the placeholder when querying the database.
+
+An example configuration might look like this:
+
+  mysql-query = select data from voip.files where id = %llu
+
+=item B<--endpoint-learning=>B<delayed>|B<immediate>|B<off>|B<heuristic>
+
+Chooses one of the available algorithms to learn RTP endpoint addresses. The
+legacy setting is B<delayed> which waits 3 seconds before committing to an
+endpoint address, which is then learned from the first incoming RTP packet seen
+after this delay. The setting B<immediate> learns the endpoint address from the
+first incoming packet seen without the 3-second delay. Using B<off> disables
+endpoint learning altogether, likely breaking clients behind NAT. The setting
+B<heuristic> includes the 3-second delay, but source addresses seen from
+incoming RTP packets are ranked according to preference: If a packet with a
+source address and port matching the SDP address is seen, this address is used.
+Otherwise, if a packet with a matching source address (but a different port) is
+seen, that address is used. Otherwise, if a packet with a matching source port
+(but different address) is seen, that address is used. Otherwise, the source
+address of any incoming packet seen is used.
+
+=item B<--jitter-buffer=>I<INT>
+
+Size of (incoming) jitter buffer in packets. A value of zero (the default)
+disables the jitter buffer. The jitter buffer is currently only implemented for
+userspace operation.
+
+=item B<--jb-clock-drift>
+
+Enable clock drift compensation for the jitter buffer.
+
+=item B<--debug-srtp>
+
+Enable extra log messages to help debug SRTP issues. Per-packet details such as
+sequence numbers, ROC, payloads (plain text and encrypted), authentication
+tags, etc are recorded to the log. Every RTCP packet is logged in this way,
+while every 512th RTP packet is logged. Only applies to packets
+forwarded/processed in userspace.
+
+=item B<--reject-invalid-sdp>
+
+With this option set, refuse to process SDP bodies that could not be cleanly
+parsed, instead of skipping over the parsing error and processing the SDP
+anyway. Currently this only affects the processing of SDP bodies that end in a
+blank line.
+
+=item B<--listen-http=>[I<IP>|I<HOSTNAME>B<:>]I<PORT>
+
+=item B<--listen-https=>[I<IP>|I<HOSTNAME>B<:>]I<PORT>
+
+Enable listening for HTTP or WebSocket connections, or their TLS-secured
+counterparts HTTPS and WSS. If no interface is specified, then the listening
+socket will be bound to all interfaces.
+
+The HTTP listener supports both HTTP and WS, while the HTTPS listener supports
+both HTTPS and WSS.
+
+If HTTPS/WSS is enabled, a certificate must also be provided using the options
+below.
+
+=item B<--https-cert=>I<FILE>
+
+=item B<--https-key=>I<FILE>
+
+Provide a server certificate and corresponding private key for the HTTPS/WSS
+listener, in PEM format.
+
+=item B<--http-threads=>I<INT>
+
+Number of worker threads for HTTP/HTTPS/WS/WSS. If not specified, then the same
+number as given under B<num-threads> will be used. If no HTTP listeners are
+enabled, then no threads are created.
+
+=item B<--software-id=>I<STRING>
+
+Sets a free-form string that is used to identify this software towards external
+systems with, for example in outgoing ICE/STUN requests. Defaults to
+B<rtpengine->I<VERSION>. The string is sanitised to replace all
+non-alphanumeric characters with a dash to make it universally usable.
+
+=item B<--dtx-delay=>I<INT>
+
+Processing delay in milliseconds to handle discontinuous transmission (DTX) or
+other transmission gaps. Defaults to zero (disabled) and is applicable to
+transcoded audio streams only. When enabled, delays processing of received
+packets for the specified time (much like a jitter buffer) in order to trigger
+DTX handling when a transmission gap occurs. The decoder is then instructed to
+fill in the missing time during a transmission gap, for example by generating
+comfort noise. The delay should be configured to be higher than the expected
+incoming jitter.
+
+=item B<--max-dtx=>I<INT>
+
+Maximum duration for DTX handling in seconds. If no further RTP media is
+received within this time frame, then DTX processing will stop. Can be set to
+zero or negative to disable and keep DTX processing on indefinitely. Defaults
+to 30 seconds.
+
+=item B<--dtx-buffer=>I<INT>
+
+=item B<--dtx-lag=>I<INT>
+
+These two options together control the maximum number of packets and amount of
+audio that is allowed to be held in the DTX buffer. The B<dtx-buffer> option
+limits the number of packets held in the DTX buffer, while the B<dtx-lag>
+option limits the amount of audio (in milliseconds) to be held in the DTX
+buffer. A DTX buffer overflow is declared when both limits are exceeded, in
+which case DTX processing is sped up by B<dtx-shift> milliseconds.
+
+The defaults are 10 packets and 100 milliseconds.
+
+=item B<--dtx-shift=>I<INT>
+
+Amount of time in milliseconds that DTX processing is shifted forward (sped up)
+or backwards (delayed) in case of a DTX buffer overflow or underflow. An
+underflow occurs when RTP packets are received slower than expected, while an
+overflow occurs when packets are received faster than expected.
+
+If this value is set to zero then no adjustments of the DTX timer will be made.
+Instead, in order to keep up with the flow of received RTP packets, packets
+will be dropped or additional DTX audio will be generated as needed.
+
+=item B<--dtx-cn-params=>I<INT>
+
+Specify one comfort noise parameter. This option follows the same format as
+B<cn-payload> described below.
+
+This option is applicable to audio generated to fill in transmission gaps
+during a DTX event. The default setting is no value, which means silence will
+be generated to fill in DTX gaps.
+
+If any CN parameters are configured, the parameters will be passed to an RFC
+3389 CN decoder, and the generated comfort noise will be used to fill in DTX
+gaps.
+
+=item B<--amr-dtx=>B<native>|B<CN>
+
+Select the DTX behaviour for AMR codecs. The default is use the codec's
+internal processing: during a DTX event, a "no data" frame is passed to the
+decoder and the output is used as audio data.
+
+If B<CN> is selected here, the same DTX mechanism as other codecs use is used
+for AMR, which is to fill in DTX gaps with either silence or RFC 3389 comfort
+noise (see B<dtx-cn-params>). This also affects processing of received SID
+frames: SID frames would not be passed to the codec but instead be replaced by
+generated silence or comfort noise.
+
+=item B<--silence-detect=>I<FLOAT>
+
+Enable silence detection and specify threshold in percent. This option is
+applicable to transcoded stream only and defaults to zero (disabled).
+
+When enabled, silence detection will be performed on all transcoded audio
+streams. The threshold specified here is the sensitivity for detecting silence:
+higher thresholds result in more audio to be detected as silence, while lower
+thresholds result in less audio to be detected as silence. The threshold is
+specified as percent between zero and 100. If set to 100, then all audio would
+be detected as silence; if set to 50, then any audio that is quieter than 50%
+of the maximum volume would be detected as silence; and so on. Setting it to
+zero disables silence detection. To only detect silence that is very near or
+equal to absolute silence, set this value to a low number such as 0.01. (For
+certain codecs such as PCMA, a higher minimum threshold is required to detect
+complete silence, as their compressed payloads don't decode to actual silence
+but instead have a residual DC offset. For PCMA the minimum value is 0.013.)
+
+Audio that is detected as silence will be replaced by comfort noise as
+specified by the B<cn-payload> option (see below). Currently this is applicable
+only to RTP peers that have advertised support for the B<CN> RTP payload type,
+in which case the silence audio frames will be replaced by B<CN> RTP frames.
+
+=item B<--cn-payload=>I<INT>
+
+Specify one comfort noise parameter. This option can be given multiple times
+and the format follows RFC 3389. When specified at the command line, list the
+B<--cn-payload=> option multiple times, each one specifying a single CN
+parameter. When used in the config file, list the option only a single time and
+list multiple CN parameters separated by semicolons (e.g.
+I<cn-payload = 20;40;60>).
+
+The first CN payload value given is the noise level, specified as -dBov as per
+RFC 3389. This means that a noise level of zero corresponds to maximum volume,
+while higher numbers correspond to lower volumes. The highest allowable number
+is 127, corresponding to -127 dBov, which is near silence.
+
+Subsequent CN payload values carry spectral information (reflection
+coefficients) as per RFC 3389. Allowable values for each coefficient are
+between 0 and 254. Specifying spectral information is optional and the number
+of coefficients listed (model order) is variable.
+
+This option is applicable only to B<CN> packets generated from the silence
+detection mechanism described above. The configured CN parameters are used
+directly as payload of B<CN> packets sent by B<rtpengine>.
+
+The default values are 32 (-32 dBov) for the noise level and no spectral
+information.
+
+=item B<--player-cache>
+
+Enable caching of encoded media packets for media player. This is applicable
+for media playback initiated through the I<play media> command. When enabled
+B<rtpengine> will not simply decode given media files and then encode the media
+to RTP on demand and on the fly, but will rather decode and encode each media
+file in full the first time playback is requested, and then cache the resulting
+RTP packets in memory. This is done once for each media file and for each
+output RTP codec requested.
+
+Caching is done based on unique file name (with no consideration given to
+different file names that may point to the same file), or integer index for
+media files played from database. No verification of changing content of files
+or database entries is done. Media files provided as binary I<blob> are also
+cached, although in this case a hash over the entire media file must be
+performed, therefore this usage is not recommended.
+
+It's not possible to choose a different I<start-pos> for playback with this
+option enabled.
+
+RTP data is cached and retained in memory for the lifetime of the process.
+
+=item B<audio-buffer-length=>I<INT>
+
+Set the buffer length used by the audio player (see below) in milliseconds. The
+default is 500 milliseconds.
+
+The buffer must be long enough to accommodate at least two frames of audio from
+all contributing sources, which means at least 40 ms or 60 ms for most cases.
+If media playback (via the B<play media>) command is desired, then the buffer
+must be able to accommodate at least one full frame from the source media file,
+whose length can vary depending on the format of the source media file. For 8
+kHz B<.wav> files this is 256 ms (2048 samples). Therefore 500 ms is the
+recommended value.
+
+=item B<audio-buffer-delay=>I<INT>
+
+Initial delay for new sources contributing to an audio buffer (used by the
+audio player, see below) in milliseconds. The default is 5 ms.
+
+The initial delay is meant to compensate for varying inter-arrival times of
+media packets (jitter). If set too low, intermittent high jitter will result in
+gaps in the output audio. If set too high, output audio will have an
+unnecessary latency added to it.
+
+=item B<audio-player=>B<on-demand>|B<play-media>|B<transcoding>|B<always>
+
+Define when to enable the audio player if not explicitly instructed otherwise.
+The default setting is B<on-demand>.
+
+Enabling the audio player for a party to a call makes B<rtpengine> produce its
+own audio RTP stream (instead of just forwarding an audio stream received from
+elsewhere). The audio is generated from a circular audio buffer (see above) and
+all contributing audio sources are mixed into that one audio buffer.
+Contributing audio sources are audio streams received from elsewhere (that
+would otherwise simply be forwarded) and audio produced by the B<play media>
+command.
+
+With this set to B<on-demand>, the audio player is enabled only if explicitly
+requested by the user for a particular call via the B<audio-player=> option
+used in a signalling message.
+
+When set to B<play-media>, the audio player is enabled only while media
+playback via the B<play media> command is active. After media playback is
+finished, the audio player is again disabled and audio goes back to simply
+being forwarded.
+
+Setting this option to B<transcoding> leaves the audio player disabled unless
+any sort of transcoding is required for a call.
+
+With a setting of B<always>, the audio player is enabled for all calls, unless
+explicitly disabled via the B<audio-player=> option used in a signalling
+message. This forces all audio through the transcoding engine, even if input
+and output codecs are the same.
+
+Audio player usage can be changed on a call-by-call basis by including the
+B<audio-player=> option in a signalling message. This option supports the
+values B<transcoding> and B<always>, which result in the behaviour described
+just above, and B<off> which forces the audio player to be disabled regardless
+of this setting.
+
+=item B<--poller-per-thread>
+
+Enable 'poller per thread' functionality: for every worker thread (see the
+--num-threads option) a poller will be created. With this option on, it is
+guaranteed that only a single thread will ever read from a particular socket,
+thus maintaining the order of the packets. Might help when having issues with
+DTMF packets (RFC 2833).
+
+=item B<--dtls-cert-cipher=>B<prime256v1>|B<RSA>
+
+Choose the type of key to use for the signature used by the self-signed
+certificate used for DTLS. The previous default was B<RSA>. The current default
+and the only other option is B<prime256v1> which is a 256-bit elliptic-curve
+key.
+
+=item B<--dtls-signature=>B<SHA-256>|B<SHA-1>
+
+Choose the hash algorithm to use for the signature used by the self-signed
+certificate used for DTLS. The default is B<SHA-256>. Not to be confused with
+the hash algorithm used for the certificate fingerprint inserted into the SDP
+(B<a=fingerprint:>), which is independent of the certificate's signature and
+can be selected during runtime.
+
+=item B<--dtls-rsa-key-size=>I<INT>
+
+Size in bits of the RSA key used by the DTLS certificate, if RSA is in use.
+Default is 2048 bits.
+
+=item B<--dtls-ciphers=>I<STRING>
+
+Ciphers allowed during the DTLS key exchange (not to be confused with the
+cipher used by the DTLS certificate). The format of this string is an OpenSSL
+cipher list. The default is
+B<DEFAULT:!NULL:!aNULL:!SHA256:!SHA384:!aECDH:!AESGCM+AES256:!aPSK>
+
+=item B<--dtls-mtu=>I<INT>
+
+Set DTLS MTU to enable fragmenting of large DTLS packets. Defaults to 1200.
+Minimum value is 576 as the internet protocol requires that hosts must be able to 
+process IP datagrams of at least 576 bytes (for IPv4) or 1280 bytes (for IPv6).
+This does not preclude link layers with an MTU smaller than this minimum MTU from 
+conveying IP data. Internet IPv4 path MTU is 68 bytes.
+
+=item B<--mqtt-host=>I<HOST>|I<IP>
+
+Host or IP address of the Mosquitto broker to connect to. Must be set to enable
+exporting stats to Mosquitto.
+
+=item B<--mqtt-port=>I<INT>
+
+Port of the Mosquitto broker. Defaults to 1883.
+
+=item B<--mqtt-id=>I<STRING>
+
+Client ID to use for Mosquitto. Default is a generated random string.
+
+=item B<--mqtt-keepalive=>I<INT>
+
+Keepalive interval in seconds. Defaults to 30.
+
+=item B<--mqtt-user=>I<USERNAME>
+
+=item B<--mqtt-pass=>I<PASSWORD>
+
+Credentials to connect to Mosquitto broker. At least a username must be given
+to enable authentication.
+
+=item B<--mqtt-cafile=>I<FILE>
+
+=item B<--mqtt-capath=>I<PATH>
+
+=item B<--mqtt-certfile=>I<FILE>
+
+=item B<--mqtt-keyfile=>I<FILE>
+
+=item B<--mqtt-tls-alpn=>I<STRING>
+
+Enable TLS to connect to Mosquitto broker, optionally with client certificate
+authentication. At least B<cafile> or B<capath> must be given to enable TLS. To
+enable client certificate authentication, both B<certfile> and B<keyfile> must
+be set. All files must be in PEM format. Password-proteted files are not
+supported. The B<tls-alpn> can be set (e.g. mqtt) if a service like AWS IoT
+Core shares the same TLS port for two different network protocols.
+
+=item B<--mqtt-publish-qos=>B<0>|B<1>|B<2>
+
+QoS value to use for publishing to Mosquitto. See Mosquitto docs for details.
+
+=item B<--mqtt-publish-topic=>I<STRING>
+
+Topic string to use for publishing to Mosquitto. Must be set to a non-empty
+string.
+
+=item B<--mqtt-publish-interval=>I<MILLISECONDS>
+
+Interval in milliseconds to publish to Mosquitto. Defaults to 5000 (5 seconds).
+
+=item B<--mqtt-publish-scope=>B<global>|B<summary>|B<call>|B<media>
+
+When set to B<summary>, one message will be published to Mosquitto every
+I<interval> milliseconds containing all global stats. A setting of B<global>
+has the same effect as B<summary> but will also contain a list of all running
+calls with stats for each call. When set to B<call>, one message per call will
+be published to Mosquitto with stats for that call every I<interval>
+milliseconds, plus one message every I<interval> milliseconds with global
+stats. When set to B<media>, one message per call media (usually one media per
+call participant, so usually 2 media per call) will be published to Mosquitto
+with stats for that call media every I<interval> milliseconds, plus one message
+every I<interval> milliseconds with global stats.
+
+=item B<--mos=>B<CQ>|B<LQ>
+
+MOS (Mean Opinion Score) calculation formula. Defaults to B<CQ> (conversational
+quality) which takes RTT into account and therefore requires peers to correctly
+send RTCP. If set to B<LQ> (listening quality) RTT is ignored, allowing a MOS to
+be calculated in the absence of RTCP.
+
+=item B<--measure-rtp>
+
+Enable measuring RTP metrics even for plain RTP passthrough scenarios. Without
+that option, RTP metrics are measured only in transcoding scenarios.
+
+=item B<--socket-cpu-affinity=>I<INT>
+
+Enables setting the socket CPU affinity via the B<SO_INCOMING_CPU> socket
+option if available. The default value is zero which disables this feature. If
+set to a positive number then the CPU affinity for all sockets belonging to the
+same call will be set to the same value. The number specifies the upper limit
+of the affinity to be set, and values will be used in a round-robin fashion
+(e.g. if set to B<8> then the values B<0> through B<7> will be used to set the
+affinity). If this option is set to a negative number, then the number of
+available CPU cores will be used.
+
+=back
+
+=head1 INTERFACES
+
+The command-line options B<-i> or B<--interface>, or equivalently the
+B<interface> config file option, specify local network interfaces for RTP.
+At least one must be given, but multiple can be specified.
+The format of the value is [I<NAME>B</>]I<IP>[!I<IP>] with I<IP> being
+either an IPv4 address, an IPv6 address, the name of a system network interface
+(such as I<eth0>), a DNS host name (such as I<test.example.com>), or B<any>.
+
+The possibility of configuring a network interface by name rather than
+by address should not be confused with the logical interface name used
+internally by B<rtpengine> (as described below).
+The I<NAME> token in the syntax above refers to the internal logical
+interface name, while the name of a system network interface is used
+in place of the first I<IP> token in the syntax above.
+For example, to configure a logical network interface called I<int>
+using all the addresses from the existing system network interface
+I<eth0>, you would use the syntax I<int/eth0>.
+(Unless omitted, the second I<IP> token used for the advertised address
+must be an actual network address and cannot be an interface name.)
+
+If DNS host names are used instead of addresses or interface names, the lookup
+will be done only once during daemon start-up.
+
+The special keyword B<any> can be used to listen on any and all available local
+interface addresses except from loopback devices. This keyword should only be
+given once in place of a more explicit interface configuration.
+
+To configure multiple interfaces using the command-line options,
+simply present multiple B<-i> or B<--interface> options.
+When using the config file, only use a single B<interface> line,
+but specify multiple values separated by semicolons (e.g.
+I<interface = internal/12.23.34.45;external/23.34.45.54>).
+
+If an interface option is given using a system interface name in place
+of a network address, and if multiple network address are found
+configured on that network interface, then B<rtpengine> behaves as
+if multiple B<--interface> options had been specified.
+For example, if interface I<eth0> exists with both addresses
+I<192.168.1.120> and I<2001:db8:85a3::7334> configured on it, and if
+the option I<--interface=ext/eth0> is given, then B<rtpengine> would
+behave as if both options I<--interface=ext/192.168.1.120> and
+I<--interface=ext/2001:db8:85a3::7334> had been specified.
+
+The second IP address after the exclamation point is optional and can
+be used if the address to advertise in outgoing SDP bodies should be
+different from the actual local address.
+This can be useful in certain cases, such as your SIP proxy being behind NAT.
+For example, I<--interface=10.65.76.2!192.0.2.4> means that I<10.65.76.2>
+is the actual local address on the server, but outgoing SDP bodies should
+advertise I<192.0.2.4> as the address that endpoints should talk to.
+Note that you may have to escape the exclamation point from your shell
+when using command-line options, e.g. using I<\!>.
+
+Giving an interface a name (separated from the address by a slash) is
+optional; if omitted, the name B<default> is used.
+Names are useful to create logical interfaces which consist of one or
+more local addresses.
+It is then possible to instruct B<rtpengine> to use particular interfaces
+when processing an SDP message, to use different local addresses when
+talking to different endpoints.
+The most common use case for this is to bridge between one or more
+private IP networks and the public internet.
+
+For example, if clients coming from a private IP network must communicate
+their RTP with the local address I<10.35.2.75>, while clients coming from
+the public internet must communicate with your other local address
+I<192.0.2.67>, you could create one logical interface I<pub> and a second
+one I<priv> by using I<--interface=pub/192.0.2.67 --interface=priv/10.35.2.75>.
+You can then use the B<direction> option to tell B<rtpengine> which local
+address to use for which endpoints (either I<pub> or I<priv>).
+
+If multiple logical interfaces are configured, but the B<direction>
+option is not given in a particular call, then the first interface
+given on the command line will be used.
+
+It is possible to specify multiple addresses for the same logical
+interface (the same name).
+Most commonly this would be one IPv4 addrsess and one IPv6 address,
+for example: I<--interface=192.168.63.1 --interface=fe80::800:27ff:fe00:0>.
+In this example, no interface name is given, therefore both addresses
+will be added to a logical interface named B<default>.
+You would use the B<address family> option to tell B<rtpengine> which
+address to use in a particular case.
+
+It is also possible to have multiple addresses of the same family in a
+logical network interface.
+In this case, the first address (of a particular family) given for an
+interface will be the primary address used by B<rtpengine> for most
+purposes.
+Any additional addresses will be advertised as additional ICE candidates
+with increasingly lower priority.
+This is useful on multi-homed systems and allows endpoints to choose the
+best possible path to reach the RTP proxy.
+If ICE is not being used, then additional addresses will go unused,
+even though ports would still get allocated on those interfaces.
+
+Another option is to give interface names in the format I<BASE:SUFFIX>.
+This allows interfaces to be used in a round-robin fashion, useful
+for load-balancing the port ranges of multiple interfaces.
+For example, consider the following configuration:
+I<--interface=pub:1/192.0.2.67 --interface=pub:2/10.35.2.75>.
+These two interfaces can still be referenced directly by name (e.g.
+I<direction=pub:1>), but it is now also possible to reference only
+the base name (i.e. I<direction=pub>).
+If the base name is used, one of the two interfaces is selected in a
+round-robin fashion, and only if the interface actually has enough
+open ports available.
+This makes it possible to effectively increase the number of available
+media ports across multiple IP addresses.
+There is no limit on how many interfaces can share the same base name.
+
+It is possible to combine the I<BASE:SUFFIX> notation with specifying
+multiple addresses for the same interface name.
+An advanced example could be (using config file notation, and omitting
+actual network addresses):
+
+  interface = pub:1/IPv4 pub:1/IPv4 pub:1/IPv6 pub:2/IPv4 pub:2/IPv6 pub:3/IPv6 pub:4/IPv4
+
+In this example, when I<direction=pub> is IPv4 is needed as a primary
+address, either I<pub:1>, I<pub:2>, or I<pub:4> might be selected.
+When I<pub:1> is selected, one IPv4 and one IPv6 address will be used
+as additional ICE alternatives.
+For I<pub:2>, only one IPv6 is used as ICE alternative, and for I<pub:4>
+no alternatives would be used.
+When IPv6 is needed as a primary address, either I<pub:1>, I<pub:2>, or
+I<pub:3> might be selected.
+If at any given time not enough ports are available on any interface,
+it will not be selected by the round-robin algorithm.
+
+It is possible to use the round-robin algorithm even if the B<direction>
+is not given.
+If the first given interface has the I<BASE:SUFFIX> format then the
+round-robin algorithm is used and will select interfaces with the
+same I<BASE> name.
+
+If you are not using the NG protocol but rather the legacy UDP protocol
+used by the B<rtpproxy> module, the interfaces must be named B<internal>
+and B<external> corresponding to the B<i> and B<e> flags if you wish to
+use network bridging in this mode.
+
+=head1 EXIT STATUS
+
+=over
+
+=item B<0>
+
+Successful termination.
+
+=item B<1>
+
+An error occurred.
+
+=back
+
+=head1 ENVIRONMENT
+
+=over
+
+=item B<RTPENGINE_REDIS_AUTH_PW>
+
+Redis server password for persistent state storage.
+
+=item B<RTPENGINE_REDIS_WRITE_AUTH_PW>
+
+Redis server password for write operations, if B<--redis> has been
+specified, in which case the one specified in B<--redis> will be used for
+read operations only.
+
+=back
+
+=head1 FILES
+
+=over
+
+=item F</etc/rtpengine/rtpengine.conf>
+
+Configuration file.
+
+=back
+
+=head1 EXAMPLES
+
+A typical command line (enabling both UDP and NG protocols) may look like:
+
+  rtpengine --table=0 --interface=10.64.73.31 --interface=2001:db8::4f3:3d \
+    --listen-udp=127.0.0.1:22222 --listen-ng=127.0.0.1:2223 --tos=184 \
+    --pidfile=/run/rtpengine.pid
+
+=head1 SEE ALSO
+
+L<kamailio(8)>.