# &adminguide;

## Overview

This is a module that enables media streams to be proxied via an &rtp; proxy. The only &rtp; proxy currently known to work with this module is Sipwise rtpengine. The rtpengine module is a modified version of the original rtpproxy module using a new control protocol. The module is designed to be a drop-in replacement for the old module from a configuration file point of view, however due to the incompatible control protocol, it only works with &rtp; proxies which specifically support it.

## Recommended Version

This control module is compatible with a wide range of versions of Sipwise rtpengine. The version numbers follow the schema mrXX.Y.ZZZ, with XX being the major release number, Y the minor release number, and ZZZ the patch level suffix. Releases with Y equalling 5 are LTS releases and receive bug fixes for several years. The recommended version therefore is either the latest LTS release on the latest patch level (e.g. mr12.5.1.46), or the latest non-LTS release if newer features are desired (e.g. mr13.4.1.5).

This version of &kamailio; includes a field in the control protocol which is not supported by versions of rtpengine older than mr12.4 and will trigger a warning log message in these older versions. This is purely cosmetic.

## Usage With Multiple RTPEngine Instances

The rtpengine module can support multiple RTPEngine instances for balancing/distribution and control/selection purposes.

The module allows definition of several sets of RTPEngines. Load-balancing will be performed over a set and the admin has the ability to choose what set should be used. The set is selected via its id - the id being defined with the set. Refer to the rtpengine_sock module parameter definition for syntax description.

The balancing inside a set is done automatically by the module based on the weight of each RTPEngine from the set. The default weight is 1, if another RTPEngine should be used twice as often as the first one, one would specify the weight 2 for this server, for example.

The selection of the set is done from script prior using rtpengine_delete(), rtpengine_offer(), rtpengine_answer() or rtpengine_manage() functions - see the set_rtpengine_set() function.

Another way to select the set is to define setid_avp module parameter and assign setid to the defined avp before calling rtpengine_offer() or rtpengine_manage() function. If forwarding of the requests fails and there is another branch to try, remember to unset the avp after calling rtpengine_delete() function.

For backward compatibility reasons, a set with no id take by default the id 0. Also if no set is explicitly set before rtpengine_delete(), rtpengine_offer() or rtpengine_answer() the 0 id set will be used.

IMPORTANT: if you use multiple sets, take care and use the same set for both rtpengine_offer()/rtpengine_answer() and rtpengine_delete()!! If the set was selected using setid_avp, the avp needs to be set only once before rtpengine_offer() or rtpengine_manage() call.

From the current implementation point of view, the sets of rtpengine nodes are in shared memory(shm), so all processes can see a common list of nodes. There is no locking when setting the nodes enabled/disabled (to keep the memory access as fast as possible). Thus, problems related to node state might appear for concurrent processes that might set the nodes enabled/disabled (e.g. by fifo command). These robustness problems are overcome as follows.

If the current process sees the selected node as disabled, the node is force tested before the current process actually accepts the disabled state. If the test succeeds, the process will set the node as enabled (but other concurrent process might still see it as disabled).

If the current process sees the selected node as enabled, it does no additional checks and sends the command which will fail in case the machine is actually broken. The process will set the node as disabled (but other concurrent process might still see it as enabled).

The 'kamctl fifo' commands (including rtpengine ones) are executed by an exclusive process which operate on the same shared memory node list.

All the nodes are pinged in the beginning by all the processes, even if the node list is shared memory.

## Dependencies

### &kamailio; Modules

The following modules must be loaded before this module:

- tm module - (optional) if you want to have rtpengine_manage() fully functional

- lwsc module - (optional) if you plan to use wsapi parameter

### External Libraries or Applications

The following libraries or applications must be installed before running &kamailio; with this module loaded:

- None.

## Parameters

### `rtpengine_sock` (string)

Definition of socket(s) used to connect to (a set) &rtp; proxy. It may specify an IPv4/IPv6 UDP socket or a websocket URI.

Default value is NONE (disabled).

#### Set `rtpengine_sock` parameter

    ...
    # single rtproxy
    modparam("rtpengine", "rtpengine_sock", "udp:localhost:12221")
    # IPv6 UDP
    modparam("rtpengine", "rtpengine_sock", "udp6:localhost:12221")
    # websocket
    modparam("rtpengine", "rtpengine_sock", "ws://localhost:12221/")
    # websocket with TLS
    modparam("rtpengine", "rtpengine_sock", "wss://localhost:12221/")
    # multiple rtproxies for LB with weights (missing weight defaults to 1)
    modparam("rtpengine", "rtpengine_sock",
    	"udp:localhost:12221=2 udp:localhost:12222=1")
    # multiple sets of multiple rtproxies
    modparam("rtpengine", "rtpengine_sock",
    	"1 == udp:localhost:12221 udp:localhost:12222")
    modparam("rtpengine", "rtpengine_sock",
    	"2 == udp:localhost:12225")
    ...

### `rtpengine_disable_tout` (integer)

Once an &rtp; proxy was found unreachable and marked as disabled, the rtpengine module will not attempt to establish communication to that &rtp; proxy for rtpengine_disable_tout seconds.

Default value is 60.

Can be set at runtime, e.g.:

    			$ &sercmd; cfg.set_now_int rtpengine rtpengine_disable_tout 20

#### Set `rtpengine_disable_tout` parameter

    ...
    modparam("rtpengine", "rtpengine_disable_tout", 20)
    ...

### `aggressive_redetection` (integer)

This parameter determines what happens when all potential rtpengines are found to be unreachable. If enabled, the sip server will send pings to all rtpengines, else no rtpengine will be queried until its rtpengine_disable_tout timeout passes.

Default value is 0 (disabled).

Can be set at runtime, e.g.:

    			$ &sercmd; cfg.set_now_int rtpengine aggressive_redetection 1

#### Set `aggressive_redetection` parameter

    ...
    modparam("rtpengine", "aggressive_redetection", 1)
    ...

### `rtpengine_tout_ms` (integer)

Timeout value expressed in milliseconds in waiting for reply from &rtp; proxy.

Default value is 1000.

Can be set at runtime, e.g.:

    			$ &sercmd; cfg.set_now_int rtpengine rtpengine_tout_ms 1000

#### Set `rtpengine_tout_ms` parameter

    ...
    modparam("rtpengine", "rtpengine_tout_ms", 2000)
    ...

### `rtpengine_allow_op` (integer)

Enable this setting to allow finishing the current sessions while denying new sessions for deactivated nodes.

Nodes can be manually deactivated via kamctl command i.e. "disabled(permanent)" nodes. Probably the manually deactivated machine is still running (did not crash).

This is useful when deactivating a node for maintenance and reject new sessions but allow current ones to finish.

The behaviour is the same for a rtpengine deleted table node. When the node is deleted from the table and the table reloaded (see nh_reload_rtpp) the node actually is disabled(permanent) and hidden for display. Next time the same node will be added in the table, and the database content reloaded, the re-activated node will be updated and re-displayed.

Default value is 0 to keep the current behaviour.

If value set to 1 it will send commands to all disabled nodes for the existing call.

If value set to 2 it will send commands only to manually disabled nodes. (Not when timeout is disabled or node broken)

#### Set `rtpengine_allow_op` parameter

    ...
    modparam("rtpengine", "rtpengine_allow_op", 1)
    ...

### `queried_nodes_limit` (integer)

The total number of nodes inside a set (sets are configurable via rtpengine_sock function) to be queried before giving up establishing a session. This brings more flexibility in case checking all rtpengines would take too long. Max limit is 30.

By default all nodes in a set are tried before giving up communicating with the rtpengines.

Can be set at runtime, e.g.:

    			$ &sercmd; cfg.set_now_int rtpengine queried_nodes_limit 5

#### Set `queried_nodes_limit` parameter

    ...
    modparam("rtpengine", "queried_nodes_limit", 5)
    ...

### `rtpengine_retr` (integer)

How many times the module should retry to send and receive after timeout was generated.

Default value is 5.

Can be set at runtime, e.g.:

    			$ &sercmd; cfg.set_now_int rtpengine rtpengine_retr 5

#### Set `rtpengine_retr` parameter

    ...
    modparam("rtpengine", "rtpengine_retr", 2)
    ...

### `extra_id_pv` (string)

The parameter sets the PV definition to use when the via-branch parameter is used on rtpengine_delete(), rtpengine_offer(), rtpengine_answer() or rtpengine_manage() command.

Default is empty, the via-branch parameter may not be used then.

#### Set `extra_id_pv` parameter

    ...
    modparam("rtpengine", "extra_id_pv", "$avp(extra_id)")
    ...

### `setid_avp` (string)

The parameter defines an AVP that, if set, determines which &rtp; proxy set rtpengine_offer(), rtpengine_answer(), rtpengine_delete(), and rtpengine_manage() functions use.

There is no default value.

#### Set `setid_avp` parameter

    ...
    modparam("rtpengine", "setid_avp", "$avp(setid)")
    ...

### `force_send_interface` (string)

Forces all control messages between the &sip; proxy and the &rtp; proxy to be sent from the specified local interface. Both IPv4 and IPv6 addresses are supported. If not specified, the default interface selected by the operating system will be used. Note: when rtpengine_sock is an IPv6 link-local address, one _must_ set this parameter in order to successfully connect to RTP engine. This is necessarily because OS needs additional scope_id hint to communicate over IPv6 link locals. The scope_id is resolved based on the given IPv6.

There is no default value.

#### Set `force_send_interface` parameter

    ...
    modparam("rtpengine", "force_send_interface", "10.3.7.123")
    modparam("rtpengine", "force_send_interface", "2001:8d8:1ff:10c0:9a90:96ff:fea8:fd99")
    ...

### `read_sdp_pv` (string)

If this parameter is set to a valid AVP or script var specifier, rtpengine will take the input SDP from this pv instead of the message body.

There is no default value.

#### Set `read_sdp_pv` parameter

    ...
    modparam("rtpengine", "read_sdp_pv", "$var(sdp)")
    ...
    request_route {
    	...
    	$var(sdp) = $rb + "a=foo:bar\r\n";
    	rtpengine_manage();
    }

### `write_sdp_pv` (string)

If this parameter is set to a valid AVP or script var specifier, the SDP returned by rtpengine in the offer/answer operations is returned in the specified variable instead of the message body.

There is no default value.

#### Set `write_sdp_pv` parameter

    ...
    modparam("rtpengine", "write_sdp_pv", "$avp(sdp)")
    ...
    request_route {
    	...
    	rtpengine_manage();
    	set_body("$avp(sdp)a=baz123\r\n", "application/sdp");
    }

### `write_sdp_pv_mode` (int)

If this parameter is set to 1, the returned SDP is written to pv and also set to message body.

Default value: 0 (write SDP only to pv).

#### Set `write_sdp_pv_mode` parameter

    ...
    modparam("rtpengine", "write_sdp_pv", "$avp(sdp)")
    modparam("rtpengine", "write_sdp_pv_mode", 1)
    ...
    request_route {
    	...
    	rtpengine_manage();
    	xinfo("new sdp: $avp(sdp)\n");
    }

### `rtp_inst_pvar` (string)

A pseudo variable to store the chosen RTP Engine URI. If this parameter is set, the URI of the instance chosen will be stored in the given variable.

By default, this parameter is not set.

#### Set `rtp_inst_pvar` parameter

    ...
    modparam("rtpengine", "rtp_inst_pvar", "$avp(RTP_INSTANCE)")
    ...

### `hash_table_size` (integer)

To maintain information about a selected rtp machine node for a given call, entries are added in a hashtable of (callid, node) pairs. This parameter sets the size of the hash table. Default value is 256.

NOTE: If configured size is less than 1, the size will be defaulted to 1.

#### Set `hash_table_size` parameter

    ...
    modparam("rtpengine", "hash_table_size", 123)
    ...

### `hash_table_tout` (integer)

Number of seconds after an rtpengine hash table entry is marked for deletion. By default, this parameter is set to 3600 (seconds).

To maintain information about a selected rtp machine node for a given call, entries are added in a hashtable of (callid, node) pairs. When command comes the callid is looked up in this table. If found, the chosen node is used. If not found, choose a new node, insert the callid in the hashtable and return the chosen node.

NOTE: In the current implementation, the actual deletion happens on the fly, while insert/remove/lookup the hastable, only for the entries in the insert/remove/lookup path.

NOTE: When configuring this parameter, one should consider maximum call time VS shared memory for unfinished calls.

#### Set `hash_table_tout` parameter

    ...
    modparam("rtpengine", "hash_table_tout", 300)
    ...

### `db_url` (string)

The rtpengine database url. If present and valid, it activates database mode. In this mode the node information is read from database, not from configuration modparam parameters.

By default, the database url is NULL (not set).

#### Set `db_url` parameter

    ...
    modparam("rtpengine", "db_url", "mysql://pass@localhost/db")
    ...

### `table_name` (string)

The rtpengine table name. If database mode is activated (i.e. valid db_url), sets the name of the rtpengine table, on startup.

By default, the rtpengine table name is "rtpengine".

NOTE: One needs to add the version of the rtpengine table in the version table. The current version is version 1.

#### Set `table_name` parameter

    ...
    modparam("rtpengine", "table_name", "rtpengine_table_name")
    ...

#### Se tup `rtpengine` table

    mysql> describe rtpengine;
    +----------+------------------+------+-----+---------------------+-------+
    | Field    | Type             | Null | Key | Default             | Extra |
    +----------+------------------+------+-----+---------------------+-------+
    | setid    | int(10) unsigned | NO   | PRI | 0                   |       |
    | url      | varchar(64)      | NO   | PRI | NULL                |       |
    | weight   | int(10) unsigned | NO   |     | 1                   |       |
    | disabled | int(1)           | NO   |     | 0                   |       |
    | stamp    | datetime         | NO   |     | 1900-01-01 00:00:01 |       |
    +----------+------------------+------+-----+---------------------+-------+

    mysql> select * from rtpengine;
    +-------+----------------------------+--------+----------+---------------------+
    | setid | url                        | weight | disabled | stamp               |
    +-------+----------------------------+--------+----------+---------------------+
    |     0 | udp:rtpengine1.domain:8800 |      1 |        0 | 2016-03-10 10:30:54 |
    |     0 | udp:rtpengine2.domain:8800 |      1 |        1 | 2016-03-10 10:30:54 |
    +-------+----------------------------+--------+----------+---------------------+

    mysql> select * from version;
    +---------------------------+---------------+
    | table_name                | table_version |
    +---------------------------+---------------+
    | rtpengine                 |             1 |
    +---------------------------+---------------+

### `setid_col` (string)

Column name for the "setid" in the rtpengine table. If database mode is activated (i.e. valid db_url), set the setid of rtp nodes according to this column, on startup. The MySQL value for this column should be INT UNSIGNED.

By default, the column name is "setid".

#### Set `setid_col` parameter

    ...
    modparam("rtpengine", "setid_col", "setid_column_name")
    ...

### `url_col` (string)

Column name for the url in the rtpengine table. If database mode is activated (i.e. valid db_url), set the url of rtp nodes according to this column, on startup. The MySQL value for this column should be VARCHAR.

By default, the column name is "url".

#### Set `url_col` parameter

    ...
    modparam("rtpengine", "url_col", "url_column_name")
    ...

### `weight_col` (string)

Column name for weight in the rtpengine table. If database mode is activated (i.e. valid db_url), set the weight of rtp nodes according to this column, on startup. The column value has priority over the URL weight. The MySQL value for this column should be INT UNSIGNED.

By default, the column name is "weight".

#### Set `weight_col` parameter

    ...
    modparam("rtpengine", "weight_col", "weight_column_name")
    ...

### `disabled_col` (string)

Column name in the rtpengine table. If database mode is activated (i.e. valid db_url), set the state of rtp nodes according to this column, on startup. The MySQL value for this column should be INT.

By default, the column name is "disabled".

#### Set `disabled_col` parameter

    ...
    modparam("rtpengine", "disabled_col", "disabled_column_name")
    ...

### `setid_default` (integer)

The default set of nodes to be used.

By default, the setid is 0.

NOTE that if setid_avp is configured, this value will be ignored and the active set will be chosen according to the setid_avp.

#### Set `setid_default` parameter

    ...
    modparam("rtpengine", "setid_default", 11)
    ...

### `media_duration` (string)

The name of a pseudovariable to be filled in with the length of the media being played back after a call to play_media, expressed in milliseconds. It's set to -1 if the length of the media could not be determined.

By default, this parameter is not set.

#### Set `media_duration` parameter

    ...
    modparam("rtpengine", "media_duration", "$avp(MEDIA_DURATION)")
    ...

### `mos_min_pv` (string)

The name of a pseudovariable to hold the minimum encountered MOS (Mean Opinion Score) value for the call. The value typically has a range of 1.0 through 5.0.

There is no default value.

This value is filled in after invoking rtpengine_delete, rtpengine_query, or rtpengine_manage if the command resulted in a deletion of the call (or call branch).

#### Set `mos_min_pv` parameter

    ...
    modparam("rtpengine", "mos_min_pv", "$avp(mos_min)")
    ...

### `mos_min_at_pv` (string)

The name of a pseudovariable to hold the timestamp of when the minimum MOS value was encountered during the call, such as 0:30 for 30 seconds after the start of the call.

There is no default value.

This value is filled in after invoking rtpengine_delete, rtpengine_query, or rtpengine_manage if the command resulted in a deletion of the call (or call branch).

#### Set `mos_min_at_pv` parameter

    ...
    modparam("rtpengine", "mos_min_at_pv", "$avp(mos_min_at)")
    ...

### `mos_min_packetloss_pv` (string)

The name of a pseudovariable to hold the amount of packetloss in percent at the time the minimum MOS value was encountered;

There is no default value.

This value is filled in after invoking rtpengine_delete, rtpengine_query, or rtpengine_manage if the command resulted in a deletion of the call (or call branch).

#### Set `mos_min_packetloss_pv` parameter

    ...
    modparam("rtpengine", "mos_min_packetloss_pv", "$avp(mos_min_packetloss)")
    ...

### `mos_min_jitter_pv` (string)

The name of a pseudovariable to hold the amount of jitter in milliseconds at the time the minimum MOS value was encountered;

There is no default value.

This value is filled in after invoking rtpengine_delete, rtpengine_query, or rtpengine_manage if the command resulted in a deletion of the call (or call branch).

#### Set `mos_min_jitter_pv` parameter

    ...
    modparam("rtpengine", "mos_min_jitter_pv", "$avp(mos_min_jitter)")
    ...

### `mos_min_roundtrip_pv` (string)

The name of a pseudovariable to hold the packet round-trip time in microseconds at the time the minimum MOS value was encountered;

There is no default value.

This value is filled in after invoking rtpengine_delete, rtpengine_query, or rtpengine_manage if the command resulted in a deletion of the call (or call branch).

#### Set `mos_min_roundtrip_pv` parameter

    ...
    modparam("rtpengine", "mos_min_roundtrip_pv", "$avp(mos_min_roundtrip)")
    ...

### `mos_max_pv` (string)

The name of a pseudovariable to hold the maximum encountered MOS value for the call. The value typically has a range of 1.0 through 5.0.

There is no default value.

This value is filled in after invoking rtpengine_delete, rtpengine_query, or rtpengine_manage if the command resulted in a deletion of the call (or call branch).

#### Set `mos_max_pv` parameter

    ...
    modparam("rtpengine", "mos_max_pv", "$avp(mos_max)")
    ...

### `mos_max_at_pv` (string)

The name of a pseudovariable to hold the timestamp of when the maximum MOS value was encountered during the call, such as 0:30 for 30 seconds after the start of the call.

There is no default value.

This value is filled in after invoking rtpengine_delete, rtpengine_query, or rtpengine_manage if the command resulted in a deletion of the call (or call branch).

#### Set `mos_max_at_pv` parameter

    ...
    modparam("rtpengine", "mos_max_at_pv", "$avp(mos_max_at)")
    ...

### `mos_max_packetloss_pv` (string)

The name of a pseudovariable to hold the amount of packetloss in percent at the time the maximum MOS value was encountered;

There is no default value.

This value is filled in after invoking rtpengine_delete, rtpengine_query, or rtpengine_manage if the command resulted in a deletion of the call (or call branch).

#### Set `mos_max_packetloss_pv` parameter

    ...
    modparam("rtpengine", "mos_max_packetloss_pv", "$avp(mos_max_packetloss)")
    ...

### `mos_max_jitter_pv` (string)

The name of a pseudovariable to hold the amount of jitter in milliseconds at the time the maximum MOS value was encountered;

There is no default value.

This value is filled in after invoking rtpengine_delete, rtpengine_query, or rtpengine_manage if the command resulted in a deletion of the call (or call branch).

#### Set `mos_max_jitter_pv` parameter

    ...
    modparam("rtpengine", "mos_max_jitter_pv", "$avp(mos_max_jitter)")
    ...

### `mos_max_roundtrip_pv` (string)

The name of a pseudovariable to hold the packet round-trip time in microseconds at the time the maximum MOS value was encountered;

There is no default value.

This value is filled in after invoking rtpengine_delete, rtpengine_query, or rtpengine_manage if the command resulted in a deletion of the call (or call branch).

#### Set `mos_max_roundtrip_pv` parameter

    ...
    modparam("rtpengine", "mos_max_roundtrip_pv", "$avp(mos_max_roundtrip)")
    ...

### `mos_average_pv` (string)

The name of a pseudovariable to hold the average (median) MOS value for the call. The value typically has a range of 1.0 through 5.0.

There is no default value.

This value is filled in after invoking rtpengine_delete, rtpengine_query, or rtpengine_manage if the command resulted in a deletion of the call (or call branch).

#### Set `mos_average_pv` parameter

    ...
    modparam("rtpengine", "mos_average_pv", "$avp(mos_average)")
    ...

### `mos_average_packetloss_pv` (string)

The name of a pseudovariable to hold the average (median) amount of packetloss in percent present throughout the call.

There is no default value.

This value is filled in after invoking rtpengine_delete, rtpengine_query, or rtpengine_manage if the command resulted in a deletion of the call (or call branch).

#### Set `mos_average_packetloss_pv` parameter

    ...
    modparam("rtpengine", "mos_average_packetloss_pv", "$avp(mos_average_packetloss)")
    ...

### `mos_average_jitter_pv` (string)

The name of a pseudovariable to hold the average (median) amount of jitter in milliseconds present throughout the call.

There is no default value.

This value is filled in after invoking rtpengine_delete, rtpengine_query, or rtpengine_manage if the command resulted in a deletion of the call (or call branch).

#### Set `mos_average_jitter_pv` parameter

    ...
    modparam("rtpengine", "mos_average_jitter_pv", "$avp(mos_average_jitter)")
    ...

### `mos_average_roundtrip_pv` (string)

The name of a pseudovariable to hold the average (median) packet round-trip time in milliseconds present throughout the call.

There is no default value.

This value is filled in after invoking rtpengine_delete, rtpengine_query, or rtpengine_manage if the command resulted in a deletion of the call (or call branch).

#### Set `mos_average_roundtrip_pv` parameter

    ...
    modparam("rtpengine", "mos_average_roundtrip_pv", "$avp(mos_average_roundtrip)")
    ...

### `mos_average_samples_pv` (string)

The name of a pseudovariable to hold the number of samples used to determine the other average MOS data points.

There is no default value.

This value is filled in after invoking rtpengine_delete, rtpengine_query, or rtpengine_manage if the command resulted in a deletion of the call (or call branch).

#### Set `mos_average_samples_pv` parameter

    ...
    modparam("rtpengine", "mos_average_samples_pv", "$avp(mos_average_samples)")
    ...

### `mos_A_label_pv` (string)

The name of a pseudovariable to hold a custom label used in rtpengine signalling. If set, all the statistics pseudovariables with the _A suffix will be filled in with statistics only from the call legs that match the label given in this variable. You need to fill this variable before invoking rtpengine_delete, rtpengine_query, or rtpengine_manage. Variable value should match the label= flag on rtpengine_offer, rtpengine_answer, or rtpengine_manage.

There is no default value.

#### Set `mos_A_label_pv` parameter

    ...
    modparam("rtpengine", "mos_A_label_pv", "$avp(mos_A_label)")
    ...

### `mos_min_A_pv` (string)

The name of a pseudovariable to hold the minimum encountered MOS value for the call. The value typically has a range of 1.0 through 5.0.

There is no default value.

This value is filled in after invoking rtpengine_delete, rtpengine_query, or rtpengine_manage if the command resulted in a deletion of the call (or call branch).

Only call legs matching the rtpengine label given in the mos_A_label_pv will be used in calculating this statistics value.

#### Set `mos_min_A_pv` parameter

    ...
    modparam("rtpengine", "mos_min_A_pv", "$avp(mos_min_A)")
    ...

### `mos_min_at_A_pv` (string)

The name of a pseudovariable to hold the timestamp of when the minimum MOS value was encountered during the call, such as 0:30 for 30 seconds after the start of the call.

There is no default value.

This value is filled in after invoking rtpengine_delete, rtpengine_query, or rtpengine_manage if the command resulted in a deletion of the call (or call branch).

Only call legs matching the rtpengine label given in the mos_A_label_pv will be used in calculating this statistics value.

#### Set `mos_min_at_A_pv` parameter

    ...
    modparam("rtpengine", "mos_min_at_A_pv", "$avp(mos_min_at_A)")
    ...

### `mos_min_packetloss_A_pv` (string)

The name of a pseudovariable to hold the amount of packetloss in percent at the time the minimum MOS value was encountered;

There is no default value.

This value is filled in after invoking rtpengine_delete, rtpengine_query, or rtpengine_manage if the command resulted in a deletion of the call (or call branch).

Only call legs matching the rtpengine label given in the mos_A_label_pv will be used in calculating this statistics value.

#### Set `mos_min_packetloss_A_pv` parameter

    ...
    modparam("rtpengine", "mos_min_packetloss_A_pv", "$avp(mos_min_packetloss_A)")
    ...

### `mos_min_jitter_A_pv` (string)

The name of a pseudovariable to hold the amount of jitter in milliseconds at the time the minimum MOS value was encountered;

There is no default value.

This value is filled in after invoking rtpengine_delete, rtpengine_query, or rtpengine_manage if the command resulted in a deletion of the call (or call branch).

Only call legs matching the rtpengine label given in the mos_A_label_pv will be used in calculating this statistics value.

#### Set `mos_min_jitter_A_pv` parameter

    ...
    modparam("rtpengine", "mos_min_jitter_A_pv", "$avp(mos_min_jitter_A)")
    ...

### `mos_min_roundtrip_A_pv` (string)

The name of a pseudovariable to hold the packet round-trip time in microseconds at the time the minimum MOS value was encountered;

There is no default value.

This value is filled in after invoking rtpengine_delete, rtpengine_query, or rtpengine_manage if the command resulted in a deletion of the call (or call branch).

Only call legs matching the rtpengine label given in the mos_A_label_pv will be used in calculating this statistics value.

#### Set `mos_min_roundtrip_A_pv` parameter

    ...
    modparam("rtpengine", "mos_min_roundtrip_A_pv", "$avp(mos_min_roundtrip_A)")
    ...

### `mos_min_roundtrip_leg_A_pv` (string)

The name of a pseudovariable to hold the packet round-trip time of the specific call leg in microseconds at the time the minimum MOS value was encountered;

There is no default value.

This value is filled in after invoking rtpengine_delete, rtpengine_query, or rtpengine_manage if the command resulted in a deletion of the call (or call branch).

Only call legs matching the rtpengine label given in the mos_A_label_pv will be used in calculating this statistics value.

#### Set `mos_min_roundtrip_leg_A_pv` parameter

    ...
    modparam("rtpengine", "mos_min_roundtrip_leg_A_pv", "$avp(mos_min_roundtrip_leg_A)")
    ...

### `mos_max_A_pv` (string)

The name of a pseudovariable to hold the maximum encountered MOS value for the call. The value typically has a range of 1.0 through 5.0.

There is no default value.

This value is filled in after invoking rtpengine_delete, rtpengine_query, or rtpengine_manage if the command resulted in a deletion of the call (or call branch).

Only call legs matching the rtpengine label given in the mos_A_label_pv will be used in calculating this statistics value.

#### Set `mos_max_A_pv` parameter

    ...
    modparam("rtpengine", "mos_max_A_pv", "$avp(mos_max_A)")
    ...

### `mos_max_at_A_pv` (string)

The name of a pseudovariable to hold the timestamp of when the maximum MOS value was encountered during the call, such as 0:30 for 30 seconds after the start of the call.

There is no default value.

This value is filled in after invoking rtpengine_delete, rtpengine_query, or rtpengine_manage if the command resulted in a deletion of the call (or call branch).

Only call legs matching the rtpengine label given in the mos_A_label_pv will be used in calculating this statistics value.

#### Set `mos_max_at_A_pv` parameter

    ...
    modparam("rtpengine", "mos_max_at_A_pv", "$avp(mos_max_at_A)")
    ...

### `mos_max_packetloss_A_pv` (string)

The name of a pseudovariable to hold the amount of packetloss in percent at the time the maximum MOS value was encountered;

There is no default value.

This value is filled in after invoking rtpengine_delete, rtpengine_query, or rtpengine_manage if the command resulted in a deletion of the call (or call branch).

Only call legs matching the rtpengine label given in the mos_A_label_pv will be used in calculating this statistics value.

#### Set `mos_max_packetloss_A_pv` parameter

    ...
    modparam("rtpengine", "mos_max_packetloss_A_pv", "$avp(mos_max_packetloss_A)")
    ...

### `mos_max_jitter_A_pv` (string)

The name of a pseudovariable to hold the amount of jitter in milliseconds at the time the maximum MOS value was encountered;

There is no default value.

This value is filled in after invoking rtpengine_delete, rtpengine_query, or rtpengine_manage if the command resulted in a deletion of the call (or call branch).

Only call legs matching the rtpengine label given in the mos_A_label_pv will be used in calculating this statistics value.

#### Set `mos_max_jitter_A_pv` parameter

    ...
    modparam("rtpengine", "mos_max_jitter_A_pv", "$avp(mos_max_jitter_A)")
    ...

### `mos_max_roundtrip_A_pv` (string)

The name of a pseudovariable to hold the packet round-trip time in microseconds at the time the maximum MOS value was encountered;

There is no default value.

This value is filled in after invoking rtpengine_delete, rtpengine_query, or rtpengine_manage if the command resulted in a deletion of the call (or call branch).

Only call legs matching the rtpengine label given in the mos_A_label_pv will be used in calculating this statistics value.

#### Set `mos_max_roundtrip_A_pv` parameter

    ...
    modparam("rtpengine", "mos_max_roundtrip_A_pv", "$avp(mos_max_roundtrip_A)")
    ...

### `mos_max_roundtrip_leg_A_pv` (string)

The name of a pseudovariable to hold the packet round-trip time of the specific call leg in microseconds at the time the maximum MOS value was encountered;

There is no default value.

This value is filled in after invoking rtpengine_delete, rtpengine_query, or rtpengine_manage if the command resulted in a deletion of the call (or call branch).

Only call legs matching the rtpengine label given in the mos_A_label_pv will be used in calculating this statistics value.

#### Set `mos_max_roundtrip_leg_A_pv` parameter

    ...
    modparam("rtpengine", "mos_max_roundtrip_leg_A_pv", "$avp(mos_max_roundtrip_leg_A)")
    ...

### `mos_average_A_pv` (string)

The name of a pseudovariable to hold the average (median) MOS value for the call. The value typically has a range of 1.0 through 5.0.

There is no default value.

This value is filled in after invoking rtpengine_delete, rtpengine_query, or rtpengine_manage if the command resulted in a deletion of the call (or call branch).

Only call legs matching the rtpengine label given in the mos_A_label_pv will be used in calculating this statistics value.

#### Set `mos_average_A_pv` parameter

    ...
    modparam("rtpengine", "mos_average_A_pv", "$avp(mos_average_A)")
    ...

### `mos_average_packetloss_A_pv` (string)

The name of a pseudovariable to hold the average (median) amount of packetloss in percent present throughout the call.

There is no default value.

This value is filled in after invoking rtpengine_delete, rtpengine_query, or rtpengine_manage if the command resulted in a deletion of the call (or call branch).

Only call legs matching the rtpengine label given in the mos_A_label_pv will be used in calculating this statistics value.

#### Set `mos_average_packetloss_A_pv` parameter

    ...
    modparam("rtpengine", "mos_average_packetloss_A_pv", "$avp(mos_average_packetloss_A)")
    ...

### `mos_average_jitter_A_pv` (string)

The name of a pseudovariable to hold the average (median) amount of jitter in milliseconds present throughout the call.

There is no default value.

This value is filled in after invoking rtpengine_delete, rtpengine_query, or rtpengine_manage if the command resulted in a deletion of the call (or call branch).

Only call legs matching the rtpengine label given in the mos_A_label_pv will be used in calculating this statistics value.

#### Set `mos_average_jitter_A_pv` parameter

    ...
    modparam("rtpengine", "mos_average_jitter_A_pv", "$avp(mos_average_jitter_A)")
    ...

### `mos_average_roundtrip_A_pv` (string)

The name of a pseudovariable to hold the average (median) packet round-trip time in microseconds present throughout the call.

There is no default value.

This value is filled in after invoking rtpengine_delete, rtpengine_query, or rtpengine_manage if the command resulted in a deletion of the call (or call branch).

Only call legs matching the rtpengine label given in the mos_A_label_pv will be used in calculating this statistics value.

#### Set `mos_average_roundtrip_A_pv` parameter

    ...
    modparam("rtpengine", "mos_average_roundtrip_A_pv", "$avp(mos_average_roundtrip_A)")
    ...

### `mos_average_roundtrip_leg_A_pv` (string)

The name of a pseudovariable to hold the average (median) packet round-trip time of the specific call leg in microseconds present throughout the call.

There is no default value.

This value is filled in after invoking rtpengine_delete, rtpengine_query, or rtpengine_manage if the command resulted in a deletion of the call (or call branch).

Only call legs matching the rtpengine label given in the mos_A_label_pv will be used in calculating this statistics value.

#### Set `mos_average_roundtrip_leg_A_pv` parameter

    ...
    modparam("rtpengine", "mos_average_roundtrip_leg_A_pv", "$avp(mos_average_roundtrip_leg_A)")
    ...

### `mos_average_samples_A_pv` (string)

The name of a pseudovariable to hold the number of samples used to determine the other average MOS data points.

There is no default value.

This value is filled in after invoking rtpengine_delete, rtpengine_query, or rtpengine_manage if the command resulted in a deletion of the call (or call branch).

Only call legs matching the rtpengine label given in the mos_A_label_pv will be used in calculating this statistics value.

#### Set `mos_average_samples_A_pv` parameter

    ...
    modparam("rtpengine", "mos_average_samples_A_pv", "$avp(mos_average_samples_A)")
    ...

### `mos_B_label_pv` (string)

The name of a pseudovariable to hold a custom label used in rtpengine signalling. If set, all the statistics pseudovariables with the _B suffix will be filled in with statistics only from the call legs that match the label given in this variable. You need to fill this variable before invoking rtpengine_delete, rtpengine_query, or rtpengine_manage. Variable value should match the label= flag on rtpengine_offer, rtpengine_answer, or rtpengine_manage.

There is no default value.

#### Set `mos_B_label_pv` parameter

    ...
    modparam("rtpengine", "mos_B_label_pv", "$avp(mos_B_label)")
    ...

### `mos_min_B_pv` (string)

The name of a pseudovariable to hold the minimum encountered MOS value for the call. The value typically has a range of 1.0 through 5.0.

There is no default value.

This value is filled in after invoking rtpengine_delete, rtpengine_query, or rtpengine_manage if the command resulted in a deletion of the call (or call branch).

Only call legs matching the rtpengine label given in the mos_B_label_pv will be used in calculating this statistics value.

#### Set `mos_min_B_pv` parameter

    ...
    modparam("rtpengine", "mos_min_B_pv", "$avp(mos_min_B)")
    ...

### `mos_min_at_B_pv` (string)

The name of a pseudovariable to hold the timestamp of when the minimum MOS value was encountered during the call, such as 0:30 for 30 seconds after the start of the call.

There is no default value.

This value is filled in after invoking rtpengine_delete, rtpengine_query, or rtpengine_manage if the command resulted in a deletion of the call (or call branch).

Only call legs matching the rtpengine label given in the mos_B_label_pv will be used in calculating this statistics value.

#### Set `mos_min_at_B_pv` parameter

    ...
    modparam("rtpengine", "mos_min_at_B_pv", "$avp(mos_min_at_B)")
    ...

### `mos_min_packetloss_B_pv` (string)

The name of a pseudovariable to hold the amount of packetloss in percent at the time the minimum MOS value was encountered;

There is no default value.

This value is filled in after invoking rtpengine_delete, rtpengine_query, or rtpengine_manage if the command resulted in a deletion of the call (or call branch).

Only call legs matching the rtpengine label given in the mos_B_label_pv will be used in calculating this statistics value.

#### Set `mos_min_packetloss_B_pv` parameter

    ...
    modparam("rtpengine", "mos_min_packetloss_B_pv", "$avp(mos_min_packetloss_B)")
    ...

### `mos_min_jitter_B_pv` (string)

The name of a pseudovariable to hold the amount of jitter in milliseconds at the time the minimum MOS value was encountered;

There is no default value.

This value is filled in after invoking rtpengine_delete, rtpengine_query, or rtpengine_manage if the command resulted in a deletion of the call (or call branch).

Only call legs matching the rtpengine label given in the mos_B_label_pv will be used in calculating this statistics value.

#### Set `mos_min_jitter_B_pv` parameter

    ...
    modparam("rtpengine", "mos_min_jitter_B_pv", "$avp(mos_min_jitter_B)")
    ...

### `mos_min_roundtrip_B_pv` (string)

The name of a pseudovariable to hold the packet round-trip time in microseconds at the time the minimum MOS value was encountered;

There is no default value.

This value is filled in after invoking rtpengine_delete, rtpengine_query, or rtpengine_manage if the command resulted in a deletion of the call (or call branch).

Only call legs matching the rtpengine label given in the mos_B_label_pv will be used in calculating this statistics value.

#### Set `mos_min_roundtrip_B_pv` parameter

    ...
    modparam("rtpengine", "mos_min_roundtrip_B_pv", "$avp(mos_min_roundtrip_B)")
    ...

### `mos_min_roundtrip_leg_B_pv` (string)

The name of a pseudovariable to hold the packet round-trip time of the specific call leg in microseconds at the time the minimum MOS value was encountered;

There is no default value.

This value is filled in after invoking rtpengine_delete, rtpengine_query, or rtpengine_manage if the command resulted in a deletion of the call (or call branch).

Only call legs matching the rtpengine label given in the mos_B_label_pv will be used in calculating this statistics value.

#### Set `mos_min_roundtrip_leg_B_pv` parameter

    ...
    modparam("rtpengine", "mos_min_roundtrip_leg_B_pv", "$avp(mos_min_roundtrip_leg_B)")
    ...

### `mos_max_B_pv` (string)

The name of a pseudovariable to hold the maximum encountered MOS value for the call. The value typically has a range of 1.0 through 5.0.

There is no default value.

This value is filled in after invoking rtpengine_delete, rtpengine_query, or rtpengine_manage if the command resulted in a deletion of the call (or call branch).

Only call legs matching the rtpengine label given in the mos_B_label_pv will be used in calculating this statistics value.

#### Set `mos_max_B_pv` parameter

    ...
    modparam("rtpengine", "mos_max_B_pv", "$avp(mos_max_B)")
    ...

### `mos_max_at_B_pv` (string)

The name of a pseudovariable to hold the timestamp of when the maximum MOS value was encountered during the call, such as 0:30 for 30 seconds after the start of the call.

There is no default value.

This value is filled in after invoking rtpengine_delete, rtpengine_query, or rtpengine_manage if the command resulted in a deletion of the call (or call branch).

Only call legs matching the rtpengine label given in the mos_B_label_pv will be used in calculating this statistics value.

#### Set `mos_max_at_B_pv` parameter

    ...
    modparam("rtpengine", "mos_max_at_B_pv", "$avp(mos_max_at_B)")
    ...

### `mos_max_packetloss_B_pv` (string)

The name of a pseudovariable to hold the amount of packetloss in percent at the time the maximum MOS value was encountered;

There is no default value.

This value is filled in after invoking rtpengine_delete, rtpengine_query, or rtpengine_manage if the command resulted in a deletion of the call (or call branch).

Only call legs matching the rtpengine label given in the mos_B_label_pv will be used in calculating this statistics value.

#### Set `mos_max_packetloss_B_pv` parameter

    ...
    modparam("rtpengine", "mos_max_packetloss_B_pv", "$avp(mos_max_packetloss_B)")
    ...

### `mos_max_jitter_B_pv` (string)

The name of a pseudovariable to hold the amount of jitter in milliseconds at the time the maximum MOS value was encountered;

There is no default value.

This value is filled in after invoking rtpengine_delete, rtpengine_query, or rtpengine_manage if the command resulted in a deletion of the call (or call branch).

Only call legs matching the rtpengine label given in the mos_B_label_pv will be used in calculating this statistics value.

#### Set `mos_max_jitter_B_pv` parameter

    ...
    modparam("rtpengine", "mos_max_jitter_B_pv", "$avp(mos_max_jitter_B)")
    ...

### `mos_max_roundtrip_B_pv` (string)

The name of a pseudovariable to hold the packet round-trip time in microseconds at the time the maximum MOS value was encountered;

There is no default value.

This value is filled in after invoking rtpengine_delete, rtpengine_query, or rtpengine_manage if the command resulted in a deletion of the call (or call branch).

Only call legs matching the rtpengine label given in the mos_B_label_pv will be used in calculating this statistics value.

#### Set `mos_max_roundtrip_B_pv` parameter

    ...
    modparam("rtpengine", "mos_max_roundtrip_B_pv", "$avp(mos_max_roundtrip_B)")
    ...

### `mos_max_roundtrip_leg_B_pv` (string)

The name of a pseudovariable to hold the packet round-trip time of the specific call leg in microseconds at the time the maximum MOS value was encountered;

There is no default value.

This value is filled in after invoking rtpengine_delete, rtpengine_query, or rtpengine_manage if the command resulted in a deletion of the call (or call branch).

Only call legs matching the rtpengine label given in the mos_A_label_pv will be used in calculating this statistics value.

#### Set `mos_max_roundtrip_leg_B_pv` parameter

    ...
    modparam("rtpengine", "mos_max_roundtrip_leg_B_pv", "$avp(mos_max_roundtrip_leg_B)")
    ...

### `mos_average_B_pv` (string)

The name of a pseudovariable to hold the average (median) MOS value for the call. The value typically has a range of 1.0 through 5.0.

There is no default value.

This value is filled in after invoking rtpengine_delete, rtpengine_query, or rtpengine_manage if the command resulted in a deletion of the call (or call branch).

Only call legs matching the rtpengine label given in the mos_B_label_pv will be used in calculating this statistics value.

#### Set `mos_average_B_pv` parameter

    ...
    modparam("rtpengine", "mos_average_B_pv", "$avp(mos_average_B)")
    ...

### `mos_average_packetloss_B_pv` (string)

The name of a pseudovariable to hold the average (median) amount of packetloss in percent present throughout the call.

There is no default value.

This value is filled in after invoking rtpengine_delete, rtpengine_query, or rtpengine_manage if the command resulted in a deletion of the call (or call branch).

Only call legs matching the rtpengine label given in the mos_B_label_pv will be used in calculating this statistics value.

#### Set `mos_average_packetloss_B_pv` parameter

    ...
    modparam("rtpengine", "mos_average_packetloss_B_pv", "$avp(mos_average_packetloss_B)")
    ...

### `mos_average_jitter_B_pv` (string)

The name of a pseudovariable to hold the average (median) amount of jitter in milliseconds present throughout the call.

There is no default value.

This value is filled in after invoking rtpengine_delete, rtpengine_query, or rtpengine_manage if the command resulted in a deletion of the call (or call branch).

Only call legs matching the rtpengine label given in the mos_B_label_pv will be used in calculating this statistics value.

#### Set `mos_average_jitter_B_pv` parameter

    ...
    modparam("rtpengine", "mos_average_jitter_B_pv", "$avp(mos_average_jitter_B)")
    ...

### `mos_average_roundtrip_B_pv` (string)

The name of a pseudovariable to hold the average (median) packet round-trip time in microseconds present throughout the call.

There is no default value.

This value is filled in after invoking rtpengine_delete, rtpengine_query, or rtpengine_manage if the command resulted in a deletion of the call (or call branch).

Only call legs matching the rtpengine label given in the mos_B_label_pv will be used in calculating this statistics value.

#### Set `mos_average_roundtrip_B_pv` parameter

    ...
    modparam("rtpengine", "mos_average_roundtrip_B_pv", "$avp(mos_average_roundtrip_B)")
    ...

### `mos_average_roundtrip_leg_B_pv` (string)

The name of a pseudovariable to hold the average (median) packet round-trip time of the specific call leg in microseconds present throughout the call.

There is no default value.

This value is filled in after invoking rtpengine_delete, rtpengine_query, or rtpengine_manage if the command resulted in a deletion of the call (or call branch).

Only call legs matching the rtpengine label given in the mos_B_label_pv will be used in calculating this statistics value.

#### Set `mos_average_roundtrip_leg_B_pv` parameter

    ...
    modparam("rtpengine", "mos_average_roundtrip_leg_B_pv", "$avp(mos_average_roundtrip_leg_B)")
    ...

### `mos_average_samples_B_pv` (string)

The name of a pseudovariable to hold the number of samples used to determine the other average MOS data points.

There is no default value.

This value is filled in after invoking rtpengine_delete, rtpengine_query, or rtpengine_manage if the command resulted in a deletion of the call (or call branch).

Only call legs matching the rtpengine label given in the mos_B_label_pv will be used in calculating this statistics value.

#### Set `mos_average_samples_B_pv` parameter

    ...
    modparam("rtpengine", "mos_average_samples_B_pv", "$avp(mos_average_samples_B)")
    ...

### `dtmf_event_callid` (string)

The name of a pseudovariable to be filled in with the callid of the triggered dtmf event.

By default, this parameter is not set.

#### Set `dtmf_event_callid` parameter

    ...
    modparam("rtpengine", "dtmf_event_callid", "$avp(dtmf_event_callid)")
    ...

### `dtmf_event_source_tag` (string)

The name of a pseudovariable to be filled in with the source tag that triggered the dtmf event.

By default, this parameter is not set.

#### Set `dtmf_event_source_tag` parameter

    ...
    modparam("rtpengine", "dtmf_event_source_tag", "$avp(dtmf_event_source_tag)")
    ...

### `dtmf_event_timestamp` (string)

The name of a pseudovariable to be filled in with the timestamp when the dtmf event was triggered.

By default, this parameter is not set.

#### Set `dtmf_event_timestamp` parameter

    ...
    modparam("rtpengine", "dtmf_event_timestamp", "$avp(dtmf_event_timestamp)")
    ...

### `dtmf_event` (string)

The name of a pseudovariable to be filled in with the triggered DTMF value.

By default, this parameter is not set.

#### Set `dtmf_event` parameter

    ...
    modparam("rtpengine", "dtmf_event", "$avp(dtmf_event)")
    ...

### `control_cmd_tos` (integer)

The parameter is used to set the value of type of service (tos) for the control commands (such as rtpengine_offer(), rtpengine_answer() etc).

There is no default value. By default this feature is not used.

The values not falling into the range 0-255 will be simply ignored.

#### Set `control_cmd_tos` parameter

    ...
    modparam("rtpengine", "control_cmd_tos", 144)
    ...

### `hash_algo` (integer)

The hashing algorithm to be used in node selection algorithm. There are two possibilities: SHA1 - 1 (calculate SHA1 hash over the Call-ID) or CRC32 - 2 (calculate crc32 sum over the callid). The legacy algorithm - 0 is not available anymore. If 0 is specified the default CRC32 will be used.

Default value is 2, CRC32.

The values not falling into the range 0-2 are ignored.

#### Set `hash_algo` parameter

    ...
    ### use CRC32 instead of legacy algorithm
    modparam("rtpengine", "hash_algo", 2)
    ...

### `wsapi` (string)

Configure a backend API for websocket usage. Currently the only supported setting is lwsc (libwebsockets). If unset, then the websocket protocol cannot be used.

#### Set `wsapi` parameter

    ...
    modparam("rtpengine", "wsapi", "lwsc")
    ...

### `dtmf_events_sock` (string)

Definition of IPv4/IPv6 UDP socket used to receive dtmf events from RTPEngine.

DTMF events coming from RTPEngine will trigger rtpengine:dtmf-event route.

Default value is NONE (disabled).

#### Set `dtmf_events_sock` parameter

    ...
    modparam("rtpengine", "dtmf_events_sock", "127.0.0.1:2223")
    ...

### `ping_mode` (integer)

Specify if the RTPEngine instances have to be pinged at startup to detect if they are active. Set it to 0 to disable pinging and to 1 to activate pinging.

Default value is 1.

#### Set `ping_mode` parameter

    ...
    modparam("rtpengine", "ping_mode", 0)
    ...

## `ping_interval` (integer)

Specify the interval in seconds between pings to all rtpengines registered.

Default value is 60.

### Set `ping_interval` parameter

    ...
    modparam("rtpengine", "ping_interval", 10)
    ...

## `enable_dmq` (integer)

If set to 1, will enable DMQ replication of hashtable of (callid, node) pairs.

Important: If this parameter is enabled, the DMQ module must be loaded first - otherwise, startup will fail.

Default value is 0.

### Set `enable_dmq` parameter

    ...
    modparam("rtpengine", "enable_dmq", 1)
    ...

## `dtmf_event_source_label` (str)

## `dtmf_event_tags` (str)

## `dtmf_event_type` (str)

## `dtmf_event_source_ip` (str)

## `dtmf_event_duration` (str)

## `dtmf_event_volume` (str)

## `event_callback` (str)

## Functions

### `set_rtpengine_set(setid[, setid])`

Sets the ID of the &rtp; proxy set to be used for the next rtpengine_delete(), rtpengine_offer(), rtpengine_answer() or rtpengine_manage() command. The parameter can be an integer or a config variable holding an integer.

A second set ID can be specified to daisy-chain two &rtp; proxies. The two set IDs must be distinct from each other and there must not be any overlap in the proxies present in both sets. In this use case, the request (offer, answer, etc) is first sent to an &rtp; proxy from the first set, which rewrites the &sdp; body and sends it back to the module. The rewritten &sdp; body is then used to make another request to an &rtp; proxy from the second set, which rewrites the &sdp; body another time and sends it back to the module to be placed back into the &sip; message. This is useful if you have a set of &rtp; proxies that the caller must use, and another distinct set of &rtp; proxies that the callee must use.

This function can be used from REQUEST_ROUTE, ONREPLY_ROUTE, BRANCH_ROUTE.

#### `set_rtpengine_set` usage

    ...
    set_rtpengine_set("2");
    rtpengine_offer();
    ...

### `rtpengine_offer([flags][,via-branch])`

Rewrites &sdp; body to ensure that media is passed through an &rtp; proxy. To be invoked on INVITE for the cases the &sdp; bodies are in INVITE and 200 OK and on 200 OK when &sdp; bodies are in 200 OK and ACK.

The function will return true on success and false (-1) on various failures, like using rtp_engine_offer() on a SIP MESSAGE request or communication with rtpengine fails.

Meaning of the parameters is as follows:

- flags - flags to turn on some features.

  The flags string is a list of space-separated items. Each item is either an individual token, or a token in key=value format. The possible tokens are described below.

  - via-branch=... - Include the branch value of one of the Via headers in the request to the &rtp; proxy. Possible values are: 1 - use the first Via header; 2 - use the second Via header; auto - use the first Via header if this is a request, or the second one if this is a reply; extra - don't take the value from a header, but instead use the value of the extra_id_pv variable; next - use the branch ID generated by &kamailio; for the next outgoing branch; auto-next - use next in requests and 1 in replies; auto-extra - use extra in requests and 1 in replies. This can be used to create one media session per branch on the &rtp; proxy. When sending a subsequent delete command to the &rtp; proxy, you can then stop just the session for a specific branch when passing the flag '1' or '2' in the rtpengine_delete, or stop all sessions for a call when not passing one of those two flags there. This is especially useful if you have serially forked call scenarios where the &rtp; proxy gets an offer command for a new branch, and then a delete command for the previous branch, which would otherwise delete the full call, breaking the subsequent answer for the new branch. This flag is only supported by the Sipwise rtpengine &rtp; proxy at the moment!

  - asymmetric - flags that UA from which message is received doesn't support symmetric &rtp;. Disables learning of endpoint addresses in the Sipwise rtpengine proxy.

  - no-redis-update - this flag can be used by Kamailio in order to tell rtpengine not to persist the call into Redis upon receiving offer/answer() control commands. If flag is not set, default action is rtpengine persists call to redis.

  - force-answer - force answer, that is, only rewrite &sdp; when corresponding session already exists in the &rtp; proxy. By default is on when the session is to be completed. This is only necessary when the offer was sent by `rtpengine_offer()`, and the answer is handled by `rtpengine_manage()`.

  - direction=... - this option specifies a logical network interface and should be given exactly twice. It enables &rtp; bridging between different addresses or networks of the same family (e.g. IPv4 to IPv4). The first instance of the option specifies the interface that the originator of this message should be using, while the second instance specifies the interface that the target should be using. For example, if the &sip; message was sent by an endpoint on a private network and will be sent to an endpoint on the public internet, you would use direction=priv direction=pub if those two logical network interfaces were called priv and pub in your &rtp; proxy's configuration respectively. The direction must only be specified in for initial &sdp; offer; answers or subsequent offers can omit this option.

  - internal, external - shorthand for direction=internal and direction=external respectively. Useful for brevity or as legacy option if the &rtp; proxy only supports two network interfaces instead of multiple, arbitrarily named ones.

  - address-family=... - instructs the &rtp; proxy that the recipient of this &sdp; body expects to see addresses of a particular family. Possible values are IP4 and IP6. For example, if the &sdp; body contains IPv4 addresses but the recipient only speaks IPv6, you would use address-family=IP6 to bridge between the two address families.

    Sipwise rtpengine remembers the address family preference of each party after it has seen an &sdp; body from them. This means that normally it is only necessary to explicitly specify the address family in the offer, but not in the answer.

    Note: Please note, that this will only work properly with non-dual-stack user-agents or with dual-stack clients according to RFC6157 (which suggest ICE for Dual-Stack implementations). This short-cut will not work properly with RFC4091 (ANAT) compatible clients, which suggests having different m-lines with different IP-protocols grouped together.

  - force - instructs the &rtp; proxy to ignore marks inserted by another &rtp; proxy in transit to indicate that the session already goes through another proxy. Allows creating a chain of proxies. Not supported and ignored by Sipwise rtpengine.

  - trust-address - flags that IP address in &sdp; should be trusted. Starting with rtpengine 3.8, this is the default behaviour. In older versions, without this flag the &rtp; proxy ignores the address in the &sdp; and uses source address of the &sip; message as media address which is passed to the &rtp; proxy.

  - SIP-source-address - the opposite of trust-address. Restores the old default behaviour of ignoring endpoint addresses in the &sdp; body.

  - received-from=IP - Configure the SIP-source-address IP explicitly, which will be useful when two kamailio is cascaded where first kamailio is handling NAT and second kamailio RTPEngine.

  - replace-origin - flags that IP from the origin description (o=) should be also changed.

  - replace-session-connection - flags to change the session-level &sdp; connection (c=) IP if media description also includes connection information.

  - symmetric - flags that for the UA from which message is received, support symmetric &rtp; must be forced. Does nothing with the Sipwise rtpengine proxy as it is the default.

  - repacketize=NN - requests the &rtp; proxy to perform re-packetization of &rtp; traffic coming from the UA which has sent the current message to increase or decrease payload size per each &rtp; packet forwarded if possible. The NN is the target payload size in ms, for the most codecs its value should be in 10ms increments, however for some codecs the increment could differ (e.g. 30ms for GSM or 20ms for G.723). The &rtp; proxy would select the closest value supported by the codec. This feature could be used for significantly reducing bandwith overhead for low bitrate codecs, for example with G.729 going from 10ms to 100ms saves two thirds of the network bandwith. Not supported by Sipwise rtpengine.

  - ICE=... - controls the &rtp; proxy's behaviour regarding ICE attributes within the &sdp; body. Possible values are: force - discard any ICE attributes already present in the &sdp; body and then generate and insert new ICE data, leaving itself as the only ICE candidates; force-relay - discard any relay type ICE attributes already present in the &sdp; body and then generate and insert itself as the only ICE relay candidates; remove instructs the &rtp; proxy to discard any ICE attributes and not insert any new ones into the &sdp;. The default (if no ICE=... is given at all), new ICE data will only be generated if no ICE was present in the &sdp; originally; otherwise the &rtp; proxy will only insert itself as additional ICE candidate. Other &sdp; substitutions (c=, m=, etc) are unaffected by this flag.

  - RTP, SRTP, DTLS, AVP, AVPF - These flags control the &rtp; transport protocol that should be used towards the recipient of the &sdp;. If none of them are specified, the protocol given in the &sdp; is left untouched. Otherwise, the SRTP flag indicates that SRTP should be used, while RTP indicates that both SRTP and AVPF should not be used. AVPF indicates that the advanced RTCP profile with feedback messages should be used, and AVP indicates that the regular RTCP profile should be used. See also the next set of flags below.

  - RTP/AVP, RTP/SAVP, UDP/TLS/RTP/SAVP, RTP/AVPF, RTP/SAVPF, UDP/TLS/RTP/SAVPF - these serve as an alternative, more explicit way to select between the different &rtp; protocols and profiles supported by the &rtp; proxy. For example, giving the flag RTP/SAVPF has the same effect as giving the two flags SRTP AVPF.

  - to-tag - force inclusion of the To tag. Normally, the To tag is always included when present, except for delete messages. Including the To tag in a delete messages allows you to be more selective about which dialogues within a call are being torn down.

  - to-tag=... - use the specified string as To tag instead of the actual To tag from the &sip; message, and force inclusion of the tag in the message as per above.

  - from-tag=... - use the specified string as From tag instead of the actual From tag from the &sip; message.

  - call-id=... - use the specified string as Call-ID instead of the actual Call-ID from the &sip; message.

  - rtcp-mux-demux - if rtcp-mux (RFC 5761) was offered, make the &rtp; proxy accept the offer, but not offer it to the recipient of this message.

  - rtcp-mux-reject - if rtcp-mux was offered, make the &rtp; proxy reject the offer, but still offer it to the recipient. Can be combined with rtcp-mux-offer to always offer it.

  - rtcp-mux-offer - make the &rtp; proxy offer rtcp-mux to the recipient of this message, regardless of whether it was offered originally or not.

  - rtcp-mux-accept - if rtcp-mux was offered, make the &rtp; proxy accept the offer and also offer it to the recipient of this message. Can be combined with rtcp-mux-offer to always offer it.

  - media-address=... - force a particular media address to be used in the &sdp; body. Address family is detected automatically.

  - TOS=... - change the IP TOS value for all outgoing &rtp; packets within the entire call in both directions. Only honoured in an offer, ignored for an answer. Valid values are 0 through 255, given in decimal. If this option is not specified, the TOS value will revert to the default TOS (normally 184). A value of -1 may be used to leave the currently used TOS unchanged.

  - delete-delay=... - override the default delay (in seconds) before a call is actually deleted from memory. Can be set to zero to effectuate immediate deletion. This option only makes sense for delete operations.

  - strict-source - instructs the &rtp; proxy to check the source addresses of all incoming &rtp; packets and drop the packets if the address doesn't match.

  - media-handover - the antithesis of strict-source. Instructs the &rtp; proxy not only to accept mismatching &rtp; source addresses (as it normally would), but also to accept them as the new endpoint address of the opposite media flow. Not recommended as it allows media streams to be hijacked by an attacker.

  - DTLS=... - influence the behaviour of DTLS-SRTP. Possible values are no or off to suppress offering or accepting DTLS-SRTP, and passive to prefer participating in DTLS-SRTP in a passive role.

  - SDES-off - don't offer SDES when it normally would. In an SRTP context, this leaves DTLS-SRTP as the only other option.

  - SDES-unencrypted_srtp, SDES-unencrypted_srtcp, SDES-unauthenticated_srtp - these directly reflect the SDES session parameters from RFC 4568 and will make the &rtp; proxy offer these parameters when offering SDES.

  - SDES-encrypted_srtp, SDES-encrypted_srtcp, SDES-authenticated_srtp - the opposites of the flags above. Useful if accepting these parameters is not desired and they should be rejected instead.

  - SDES-nonew - don't add any new crypto suites into the offer. This means, offered SDES crypto suites will be accepted, meanwhile no new is going to be generated by RTPEngine. It takes precedence over the `SDES-no` and `SDES-only` flags, if used in combination.

  - SDES-pad - RFC 4568 (section 6.1) is somewhat ambiguous regarding the base64 encoding format of `a=crypto` parameters added to an SDP body. The default interpretation is that trailing `=` characters used for padding should be omitted. With this flag set, these padding characters will be left in place.

  - unidirectional - allows kernelization of one-way streams in the Sipwise rtpengine proxy. This is especially useful when the first call leg is handled by some rtpengine machine while the second call leg is handled by other rtpengine machine.

  - record-call=on - instructs RTPEngine to record the session. Use it in rtpengine_offer() to start recording immediately and save the call metadata, as alternative to start_recording().

  - metadata - a generic metadata string. The metadata will be used when recording calls to provide custom additional information. More details about this are found in the rtpengine README.

  - codec-transcode=... - allows codecs to be added to the list of offered codecs even if they were not present in the original list of codecs. In this case, the transcoding engine will be engaged. Only codecs that are supported for both decoding and encoding can be added in this manner. More details about this are found in the rtpengine README.

  - codec-set=... - set codec options (bitrate etc) for codecs that are implicitly accepted for transcoding from the offering side.

  - codec-strip=... - strips given codec from sdp

  - codec-offer=... - offer given codec from sdp. More details about this are found in the rtpengine README.

  - codec-except=... - same as codec-offer but preserves original order

  - codec-mask=... - similar to strip except that codecs listed here will still be accepted and used for transcoding on the offering side. Useful only in combination with codec-transcode. all keyword can be used to mask all offered codecs

  - codec-accept=... - similar to `mask` and `consume` but doesn't remove the codec from the list of offered codecs. This means that a codec listed under `accept` will still be offered to the remote peer, but if the remote peer rejects it, it will still be accepted towards the original offerer and then used for transcoding. It is a more selective version of what the `always transcode` flag does.

  - codec-consume=... - identical to mask but enables the transcoding engine even if no other transcoding related options are given.

  - T.38=decode - if the offered &sdp; contains a media section advertising T.38 over UDPTL, translate it to a regular audio media section over RTP. By default, PCMU and PCMA will be used as audio codecs, but that can be overridden using the codec options described above. Other transport protocols (e.g. SRTP) can also be selected in the same way. If the offered &sdp; does not contain a T.38 section, then this flag has no effect.

  - T.38=force - any audio media section (over RTP) in the offered &sdp; will be translated into a T.38 section over UDPTL.

  - T.38=stop - stops a previously established T.38 to audio gateway and reverts the session back to media passthrough. This is useful when handling a rejected T.38 offer.

  - label=... - adds a label to a current stream, that later can be used to get call quality stats, see mos_A_label_pv and mos_B_label_pv parameters.

  - debug - enables debug logging (rtpengine log level 7) for this call only. rtpengine will log everything related to that call after parsing the flags. Useful in debugging scenarios.

  Check also the documentation of RTPEngine, these flags are documented there as well: https://github.com/sipwise/rtpengine.

- via-branch - provide the via-branch taken from one of SIP message Via headers.

  The via-branch parameter helps to match NG command (offer, answer, delete etc.) to particular monologue. It does the same job as the via-branch option flag, but it also enables alternative parsing behavior, when option flags are passed to rtpengine using bencode string format and is then parsed there. The benefit of the second approach is that any new flags supported by rtpengine will automatically be supported without having to worry about support in the control module. Regardless whether the flags parsing is done by the module or daemon, a functional behavior remains the same and has no difference in terms of SDP processing. Possible values are the same as for the via-branch option flag. If the newer approach is to be applied, but no via-branch is meant to be added for identfication, then none can be given instead. This parameter can be applied for the rtpengine versions equal or later than mr12.4.

This function can be used from ANY_ROUTE.

#### `rtpengine_offer` usage

    request_route {
    ...
        if (is_method("INVITE")) {
            if (has_body("application/sdp")) {
                if (rtpengine_offer())
                    t_on_reply("1");
            } else {
                t_on_reply("2");
            }
        }
        if (is_method("ACK") && has_body("application/sdp"))
            rtpengine_answer();
    ...
    }

    onreply_route[1]
    {
    ...
        if (has_body("application/sdp"))
            rtpengine_answer();
    ...
    }

    onreply_route[2]
    {
    ...
        if (has_body("application/sdp"))
            rtpengine_offer();
    ...
    }
    ...
    if (has_body("application/sdp")) {
        if (rtpengine_offer("codec-mask=all codec-transcode=PCMU codec-transcode=PCMA"))
            t_on_reply("1");
    }

    ...

#### `rtpengine_offer` usage to force transcoding from opus to PCMU

    request_route {
    ...
        if (is_method("INVITE")) {
            if (has_body("application/sdp")) {
                if (rtpengine_offer("codec-mask=opus codec-accept=opus codec-strip=PCMU codec-transcode=PCMU"))
                    t_on_reply("1");
            }
        }
    ...
    }

    onreply_route[1]
    {
    ...
        if (has_body("application/sdp"))
            rtpengine_answer("codec-strip=PCMU codec-strip=PCMA");
    ...
    }
    ...

#### `rtpengine_offer` usage of via-branch parameter

    request_route {
    ...
        if (is_method("INVITE")) {
            if (has_body("application/sdp")) {
                if (rtpengine_offer("replace-origin replace-session-connection strict-source label=callee OSRTP-accept transport-protocol=RTP/AVP address-family=IP4", "auto-next"))
                    t_on_reply("1");
            }
        }
    ...
    }

### `rtpengine_answer([flags][,via-branch])`

Rewrites &sdp; body to ensure that media is passed through an &rtp; proxy. To be invoked on 200 OK for the cases the &sdp; bodies are in INVITE and 200 OK and on ACK when &sdp; bodies are in 200 OK and ACK.

See rtpengine_offer() function description above for the meaning of the parameters.

This function can be used from REQUEST_ROUTE, ONREPLY_ROUTE, FAILURE_ROUTE, BRANCH_ROUTE.

#### `rtpengine_answer` usage

See rtpengine_offer() function example above for example.

### `rtpengine_info([flags][,via-branch])`

Send an updated offer to rtpengine. This is meant to be used when processing Trickle ICE &sdp; Fragments that are carried in &sip; INFO messages and are proxied to endpoints that do not support ICE. With a matching content type, the &sdp; fragment is used to update rtpengine's list of ICE candidates. No new &sdp; is returned and so the &sip; INFO message should be consumed after calling this function.

While this function supports the same flags as rtpengine_offer et al, it is not normally necessary to provide any.

This function can be used from ANY_ROUTE.

#### `rtpengine_info` usage

    ...
    rtpengine_info();
    ...

### `rtpengine_delete([flags][,via-branch])`

Tears down the RTP proxy session for the current call. This populates the statistics pseudovariables (such mos_min_pv etc).

See rtpengine_offer() function description above for the meaning of the parameters. Note that not all flags make sense for a delete.

This function can be used from ANY_ROUTE.

#### `rtpengine_delete` usage

    ...
    rtpengine_delete();
    ...

### `rtpengine_destroy([flags][,via-branch])`

Same as rtpengine_delete().

#### `rtpengine_destroy` usage

    ...
    rtpengine_destroy();
    ...

### `rtpengine_query([flags][,via-branch])`

Queries the &rtp; proxy about the current status and statistics of a running call. This populates the statistics pseudovariables (such mos_min_pv etc).

See rtpengine_offer() function description above for the meaning of the parameters. Note that not all flags make sense for a query.

This function can be used from ANY_ROUTE.

#### `rtpengine_query` usage

    ...
    rtpengine_query();
    ...

### `rtpengine_query_v(fmt, var)`

Queries the &rtp; proxy about the current status and statistics of a running call, converts the response to JSON according to fmt and sets the variable var with the result.

The fmt parameter can be 'j' for compacted JSON and 'jp' for pretty-formatted JSON.

The var parameter has to be the name of a writable variable.

This function can be used from ANY_ROUTE.

#### `rtpengine_query_v` usage

    ...
    if(rtpengine_query_v("j", "$var(rdata)")) {
        xinfo("rtpengine query response: $var(rdata)\n");
    }
    ...

### `rtpengine_connect([flags][,via-branch])`

Connects the media of two call parties directly without the need for a full offer/answer exchange. The media will be connected in the same way as it would through an offer/answer exchange. Transcoding will automatically be engaged if needed.

See rtpengine_query() function description above for the meaning of the parameters. The function requires call-id, from-tag, and to-tag to identify the two call parties to connect. Optionally, to-call-id can be specified in flags to connect parties from different calls (different call IDs).

This function can be used from ANY_ROUTE.

#### `rtpengine_connect` usage

    ...
    # Connect two parties from the same call (using tags from current SIP message)
    rtpengine_connect();

    # Connect two parties from different calls, specifying all parameters
    rtpengine_connect("call-id=abc123def456@192.168.1.100 from-tag=a1b2c3d4 to-tag=e5f6g7h8 to-call-id=xyz789ghi012@192.168.1.200");
    ...

### `rtpengine_manage([flags][,via-branch])`

Manage the RTPEngine session - it combines the functionality of rtpengine_offer(), rtpengine_answer() and rtpengine_delete(), detecting internally based on message type and method which one to execute.

It can take the same parameters as `rtpengine_offer()`. The flags parameter to rtpengine_manage() can be a configuration variable containing the flags as a string.

Functionality:

- If INVITE with &sdp;, then do `rtpengine_offer()`

- If INVITE with &sdp;, when the tm module is loaded, mark transaction with internal flag FL_SDP_BODY to know that the 1xx and 2xx are for `rtpengine_answer()`

- If ACK with &sdp;, then do `rtpengine_answer()`

- If BYE or CANCEL, or called within a FAILURE_ROUTE[], then call `rtpengine_delete()`. Be careful with calling this function after resuming a suspended transaction (e.g., after t_continue()), because the context of executed route is FAILURE ROUTE (in other words, rtpengine_manage() in the route block of t_continue() does the same as in failure_route; use a branch route to engage rtpengine for a forwarded branch after resuming the transaction).

- It does nothing if used inside event_route[tm:branch-failure:...]

- If reply to INVITE with code >= 300 do `rtpengine_delete()`

- If reply with &sdp; to INVITE having code 1xx and 2xx, then do `rtpengine_answer()` if the request had &sdp; or tm is not loaded, otherwise do `rtpengine_offer()`

This function can be used from ANY_ROUTE.

#### `rtpengine_manage` usage

    ...
    rtpengine_manage();
    ...

### `rtpengine_subscribe_request(flags,sdp_avp,to_tag_avp,stream_xavp[,via-branch])`

Generates &sdp; body for forking the current &rtp; stream and stores it in the xavp specified sdp_avp AVP. The new call leg will be identified by the generated (or specified) to tag that will be put in the to_tag_avp AVP. on INVITE for the cases the &sdp; bodies are in INVITE and 200 OK and on 200 OK when &sdp; bodies are in 200 OK and ACK.

The function will return true on success and false (-1) on various failures, like using rtpengine_subscribe_request() before an rtpengine session was established.

Meaning of the parameters is as follows:

- flags - flags to turn on some features.

  The flags string is a list of space-separated items. Each item is either an individual token, or a token in key=value format. The possible tokens are described below. This offer SDP can be manipulated with the same flags as used in `rtpengine_offer` additionally, the following extra flags can be used

  - from-tags=... - Specifies which participants in the call should have their media forked. This value can be repeated multiple times to specify multiple participants. To specify all participants, use all as an alternative.

  - all - forks the media stream for all participants in the call. Use instead of from-tags=...

  - siprec - indicates that the &sdp; should be in SIPREC format. The flag all should also be used in this case.

  Check also the documentation of RTPEngine, these flags are documented there as well: https://github.com/sipwise/rtpengine.

- sdp_avp - the name of the AVP where the generated &sdp; will be stored.

  The sdp_avp parameter is mandatory and must be a writable AVP. The AVP will be set to the generated &sdp; body, which can then be used in a subsequent t_uac_send() call to send the offer to the new participant.

- to_tag_avp - the name of the AVP where to store the to tag of the new call leg.

  The to_tag_avp parameter is mandatory and must be a writable AVP. The to tag will either be auto generated or taken from the value specified in the to-tag flag.

- stream_xavp - XAVP to store the stream information.

  The stream_xavp parameter is mandatory and must be a writable XAVP. The XAVP will be a stack, one for each participant. Each stack element will have a key tag to identify the participant, and a key label which is an array of labels, (each stream in the &rtp; will have a label attribute in the generated &sdp;).

- via-branch - provide the via-branch taken from one of SIP message Via headers.

  The via-branch parameter helps to match NG command (offer, answer, delete etc.) to particular monologue. It does the same job as the via-branch option flag, but it also enables alternative parsing behavior, when option flags are passed to rtpengine using bencode string format and is then parsed there. The benefit of the second approach is that any new flags supported by rtpengine will automatically be supported without having to worry about support in the control module. Regardless whether the flags parsing is done by the module or daemon, a functional behavior remains the same and has no difference in terms of SDP processing. Possible values are the same as for the via-branch option flag. If the newer approach is to be applied, but no via-branch is meant to be added for identfication, then none can be given instead. This parameter can be applied for the rtpengine versions equal or later than mr12.4.

- via-branch - provide the via-branch taken from one of SIP message Via headers.

  The via-branch parameter helps to match NG command (offer, answer, delete etc.) to particular monologue. It does the same job as the via-branch option flag, but it also enables alternative parsing behavior, when option flags are passed to rtpengine using bencode string format and is then parsed there. The benefit of the second approach is that any new flags supported by rtpengine will automatically be supported without having to worry about support in the control module. Regardless whether the flags parsing is done by the module or daemon, a functional behavior remains the same and has no difference in terms of SDP processing. Possible values are the same as for the via-branch option flag. If the newer approach is to be applied, but no via-branch is meant to be added for identfication, then none can be given instead. This parameter can be applied for the rtpengine versions equal or later than mr12.4.

This function can be used from ANY_ROUTE.

#### `rtpengine_subscribe_request` usage

    request_route {
    ...
        if (is_method("INVITE")) {
            if (has_body("application/sdp")) {
                if (rtpengine_offer())
                    t_on_reply("1");
            }
        }
    ...
    }

    onreply_route[1]
    {
    ...
        if (has_body("application/sdp")) {
            rtpengine_answer();
            rtpengine_subscribe_request("all siprec", "$avp(siprec_offer)",
                                        "$avp(siprec_to_tag)", "siprec_streams");
            xinfo("SIPREC participant $xavp(siprec_streams[0]=>tag) with label $xavp(siprec_streams[0]=>label[0])\n");
            xinfo("SIPREC participant $xavp(siprec_streams[1]=>tag) with label $xavp(siprec_streams[0]=>label[0])\n");
            # use the above stream information to build the siprec xml metadata, will just send SDP in this example
            $dlg_var(orig_to_tag) = $tt;
            $dlg_var(siprec_contact) = "sip:uac@" + $Ri;
            $dlg_var(siprec_to_tag) = $avp(siprec_to_tag);
            t_uac_send("INVITE" ,"sip:siprec@siprec_server.example.com",
                       "siprec_server.example.com", "",
                       "To: <$tu>\r\n" +
                       "From: <$fu>\r\n" +
                       "Contact: <$dlg_var(siprec_contact)>\r\n" +
                       "Content-Type: application/sdp\r\n",
                       $avp(siprec_offer));
    	}
    ...
    }

    event_route [tm:local-request] {
        if (is_method("INVITE")) {
            # save information from the original dialog to the new invite transaction
            $avp(orig_callid) = $dlg(callid);
            $avp(orig_from_tag) = $dlg(from_tag);
            $avp(orig_to_tag) = $dlg_var(orig_to_tag);
            $avp(siprec_to_tag) = $dlg_var(siprec_to_tag);
            $avp(siprec_contact) = $dlg_var(siprec_contact);
            t_on_reply("2");
        }
        if (is_method("ACK")) {
            # save the route set in the original dialog
            dlg_get($avp(orig_callid), $avp(orig_from_tag), $avp(orig_to_tag));
            $dlg_var(siprec_cseq) = $cs;
            $dlg_var(siprec_to_hdr) = $hdr(To);
            $dlg_var(siprec_from_hdr) = $hdr(From);
            append_hf("Contact: <$dlg_var(siprec_contact)>\r\n");

            # the same dialog information can be used to send the BYE with t_uac_send
        }
    }

    onreply_route[2] {
        if (has_body("application/sdp")) {
           rtpengine_subscribe_answer("from-tag=$avp(orig_from_tag) to-tag=$avp(siprec_to_tag) call-id="$avp(orig_callid)");
        }
    }
    ...

### `rtpengine_subscribe_answer([flags][,via-branch])`

Sends the &sdp; answer from the recording server to the rtpengine

This function can be used from REQUEST_ROUTE, ONREPLY_ROUTE, FAILURE_ROUTE, BRANCH_ROUTE.

Meaning of the parameters is as follows:

- flags - flags to turn on some features.

  The flags string is a list of space-separated items. Each item is either an individual token, or a token in key=value format. The possible tokens are described below. This offer SDP can be manipulated with the same flags as used in `rtpengine_offer` additionally, the following extra flags can be used

  - to-tag=... - value of the to tag returned by rtpengine_subscribe_request

  - from-tag=... - value of the from tag of the original call.

  - call-id=... - value of the call id of the original call.

#### `rtpengine_subscribe_answer` usage

See rtpengine_subscribe_request() function example above for example.

### `rtpengine_unsubscribe([flags][,via-branch])`

Sends the &sdp; answer from the recording server to the rtpengine

This function can be used from REQUEST_ROUTE, ONREPLY_ROUTE, FAILURE_ROUTE, BRANCH_ROUTE.

Meaning of the parameters is as follows:

- flags - flags to turn on some features.

  The flags string is a list of space-separated items. Each item is either an individual token, or a token in key=value format. The possible tokens are described below. This offer SDP can be manipulated with the same flags as used in `rtpengine_offer` additionally, the following extra flags can be used

  - to-tag=... - value of the to tag returned by rtpengine_subscribe_request

  - from-tag=... - value of the from tag of the original call.

  - call-id=... - value of the call id of the original call.

#### `rtpengine_unsubscribe` usage

    event_route [dialog:end] {
        # call over, stop recording
        rtpengine_unsubscribe("from-tag=$avp(orig_from_tag) to-tag=$avp(siprec_to_tag) call-id="$avp(orig_callid)");
        $var(new_cseq) = $dlg_var(siprec_cseq) + 1;
        t_uac_send("BYE", "sip:siprec@siprec_server.example.com",
                   "siprec_server.example.com", "",
                   "To: <$dlg_var(siprec_to_hdr)>\r\n" +
                   "From: <$dlg_var(siprec_from_hdr)>\r\n" +
                   "Call-ID: $avp(siprec_callid)\r\n" +
                   "CSeq: $var(new_cseq) BYE\r\n" +
                   "Contact: $lt;$dlg_var(siprec_contact)>\r\n");
    }
    ...

### `start_recording([flags])`

This function will send a signal to the &rtp; relay to record the &rtp; stream flowing through it. See also the option record-call=on for rtpengine_manage()/rtpengine_offer(), which offers an alternative for call recording, saving also call metadata from SDP.

It can take the same parameters as `rtpengine_manage()`. The flags parameter to start_recording can be a configuration variable containing the flags as a string. The call-id flag can be used to start recording for a different call.

This function can be used from REQUEST_ROUTE and ONREPLY_ROUTE.

#### `start_recording` usage

    ...
    start_recording();
    ...

### `stop_recording([flags])`

This function will send a signal to the &rtp; relay to stop recording the &rtp; stream flowing through it. See also the option record-call=off for rtpengine_manage()/rtpengine_offer(), which offers an alternative for call recording.

It can take the same parameters as `rtpengine_manage()`. The flags parameter to start_recording can be a configuration variable containing the flags as a string. The call-id flag can be used to stop recording for a different call.

This function can be used from REQUEST_ROUTE and ONREPLY_ROUTE.

#### `stop_recording` usage

    ...
    stop_recording();
    ...

### `block_dtmf([flags])`

This function will instruct the &rtp; proxy to start blocking DTMF event packets (RFC 4733). DTMF events will still be processed by the &rtp; proxy, but they won't be forwarded to the receiving peer.

The call-id flag can be used to block DTMF for a different call.

Without any flags given, DTMF events will be blocked for the entire call. It's possible to block DTMF directionally only for individual participants. If the directional flag is given, DTMF events will be blocked for the UA with the currently matching From tag. Events can be blocked for a different UA either by specifying an alternative from-tag=..., or by matching UAs against the media address they advertised in the &sdp; using the address=... flag (which can contain either an IPv4 or IPv6 address).

This function can be used from REQUEST_ROUTE and ONREPLY_ROUTE.

#### `block_dtmf` usage

    ...
    block_dtmf();
    block_dtmf("directional");
    block_dtmf("address=192.168.42.42");
    ...

### `unblock_dtmf([flags])`

Reverses the effects of a previously issued `block_dtmf` call. See above for a description of which flags can be used.

If DTMF events were previously blocked for individual UAs, then unblocking DTMF events for the entire call (i.e. no flags given) will not remove these blocks. The flag all can be used to achieve this.

#### `unblock_dtmf` usage

    ...
    unblock_dtmf();
    unblock_dtmf("all");
    ...

### `block_media([flags])`

Analogous to block_dtmf, but blocks media &rtp; packets instead of DTMF events. When media is blocked, DTMF events still pass through the &rtp; proxy.

See block_dtmf for a description of the flags that can be used.

#### `block_media` usage

    ...
    block_media();
    block_media("directional");
    block_media("address=192.168.42.42");
    ...

### `unblock_media([flags])`

Analogous to unblock_dtmf, but applies to media &rtp; packets instead of DTMF events.

See unblock_dtmf for a description of the flags that can be used.

#### `unblock_media` usage

    ...
    unblock_media();
    unblock_media("all");
    ...

### `silence_media([flags])`

Identical to block_media except that media &rtp; packets are not simply blocked, but instead have their audio payload replaced by silence audio. This is only supported for certain trivial audio codecs (e.g. G.711, G.722).

See block_dtmf for a description of the flags that can be used.

#### `silence_media` usage

    ...
    silence_media();
    silence_media("directional");
    silence_media("address=192.168.42.42");
    ...

### `unsilence_media([flags])`

Identical to unblock_media except that it's the counterpart to silence_media.

See unblock_dtmf for a description of the flags that can be used.

#### `unsilence_media` usage

    ...
    unsilence_media();
    unsilence_media("all");
    ...

### `start_forwarding([flags])`

Controls the PCM forwarding feature of the recording daemon. Unlike the recording feature, PCM forwarding can be done directionally for individual call participants only, therefore this command takes the same flags as the media/DTMF blocking commands above.

See block_dtmf for a description of the flags that can be used.

#### `start_forwarding` usage

    ...
    start_forwarding();
    start_forwarding("directional");
    start_forwarding("address=192.168.42.42");
    ...

### `stop_forwarding([flags])`

Analogous to unblock_dtmf, but controls the PCM forwarding feature instead of DTMF blocking.

See unblock_dtmf for a description of the flags that can be used.

#### `stop_forwarding` usage

    ...
    stop_forwarding();
    stop_forwarding("all");
    ...

### `play_media([flags])`

Instructs rtpengine to play a prerecorded announcement to the selected call participant, either from a local file or from a file stored in a database. The participant must be selected using the same flags as are described under the block_dtmf function. If none of these flags are given, then the From tag from the current &sip; message context is used.

If successful, the media_duration pseudovariable is filled in with the duration of the media being played, expressed in milliseconds. If the length of the media could not be determined, it's set to -1.

#### `play_media` usage

    ...
    play_media("file=/use/share/media/hello.wav");
    play_media("from-tag=tfugklbildfydrtuykgfv db-id=12345");
    ...

### `stop_media([flags])`

Stops the playback of media previously started by play_media. Media playback is automatically stopped when the end of the media file is reached, so this function is only useful to prematurely stop playback.

#### `stop_media` usage

    ...
    stop_media();
    stop_media("from-tag=5yqaeriguhxcikxj");
    ...

### `play_dtmf([flags])`

Injects a DTMF event into the media stream. Depending on which codecs were negotiated, this either injects an RFC 2833/4733 DTMF event, or an in-band PCM DTMF tone into the audio stream. The flag inject DTMF must have been present in both offer and answer messages when the call was established, which forces all audio to go through rtpengine's transcoding engine.

Usage is similar to play_media with the following exceptions. The selected party is not the party that will receive the DTMF event, but rather the party which is generating the event. This is to support DTMF events that are carried in &sip; INFO messages. Instead of specifying a media file, a DTMF event code must be specified, as well as optionally a duration and the volume. The code can be a number 0 through 15, or a DTMF digit (0-9, A-D, *, #). The duration is specified in milliseconds and defaults to 250, within a range of 100-5000. The volume is specified in absolute decibels, with a default of -8 db.

Multiple consecutive DTMF events can be queued up by calling this function multiple times consecutively. RTPengine will play out the DTMF events in sequence, separated by a default pause of 100 ms. An alternative pause length can be given through the pause option, between 100 and 5000 ms.

#### `play_dtmf` usage

    ...
    play_dtmf("from-tag=5yqaeriguhxcikxj code=#");
    play_dtmf("code=1 volume=5 duration=300 pause=150");
    ...

## Exported Pseudo Variables

### `$rtpestat`

Returns the &rtp; statistics from the &rtp; relay. The &rtp; statistics from the &rtp; relay are provided as a string and it does contain several packet counters. The statistics must be retrieved before the session is deleted (before `rtpengine_delete()`).

#### $rtpestat Usage

    ...
    append_hf("X-RTP-Statistics: $rtpestat\r\n");
    ...
    # $rtpestat = RTP: 54846 bytes, 1447 packets, 0 errors; RTCP: 336 bytes, 3 packets, 0 errors
    ...

### `$rtpstat`

Same as $rtpestat.

## RPC Commands

### `rtpengine.reload`

Reloads the database node table content if configured. Returns specific message related to success, failure and no db_url configured.

NOTE: The current behaviour updates the nodes state or creates new ones or hides old ones, based on the database content. If allow_op modparam is enabled, the sessions are still allowed to finish for the hidden old nodes.

The execution of this command is limited to 10 seconds intervals.

#### `rtpengine.reload` usage

    ...
    $ &kamctl; rpc rtpengine.reload
    ...

### `rtpengine.enable proxy_url/all 0/1`

Enables a &rtp; proxy if the second parameter value is greater than 0. Disables it if a zero value is given. The first parameter is either a specific &rtp; proxy url (exactly as defined in the config file) or the keyword all. The second parameter value must be a number in decimal.

When try to enable the &rtp; proxy, an application ping command is sent to it. If it fails, the proxy is not enabled. Displays success or fail when try to enable/disable.

NOTE: If a &rtp; proxy is defined multiple times (in the same or different sets), all of its instances will be enabled/disabled.

NOTE: If a &rtp; proxy is in the disabled permanent state and one tries to enable it, even if the ping fails, it is moved to a disabled temporary state and a recheck_ticks are given to it. While the recheck_ticks are grater than 0, the proxy is considered disabled temporary, and it is not taken into consideration for sending data. When the recheck_ticks are 0, the proxy is retested when trying to send data (not automatically retested), and data can be sent to it on success.

NOTE: If you specify an IPv6 &rtp;, the proxy url must be prefixed with :: to escape the :: from the IPv6 address. See the example below.

#### `rtpengine.enable` usage

    ...
    $ &kamctl; rpc rtpengine.enable udp:192.168.2.133:8081 0
    $ &kamctl; rpc rtpengine.enable ::udp6:fe80::9a90:96ff:fea8:fd99:9999 1
    $ &kamctl; rpc rtpengine.enable all 1
    ...

### `rtpengine.show proxy_url/all`

Displays all the &rtp; proxies and their information: set and status (disabled or not, weight and recheck_ticks). If a &rtp; proxy has been disabled by nh_enable_rtpp mi command a "(permanent)" quote will appear when printing the disabled status. This is to differentiate from a temporary disable due to the proxy being not found responsive by kamailio. In addition, when disabled permanent, recheck_ticks have no meaning and "N\A" is printed instead of the value.

It takes either a specific &rtp; proxy url (exactly as defined in the config file) or the keyword all as a parameter.

NOTE: When specify the IPv6 &rtp; proxy url one must prefix it with :: to escape the :: from the IPv6 address. See the example below.

#### `rtpengine.show` usage

    ...
    $ &kamctl; rpc rtpengine.show udp:192.168.2.133:8081
    $ &kamctl; rpc rtpengine.show ::udp6:fe80::9a90:96ff:fea8:fd99:9999
    $ &kamctl; rpc rtpengine.show all
    ...

### `rtpengine.ping proxy_url/all`

Sends an application ping command to the &rtp; proxy. If the proxy does not respond, it will be disabled, but not permanent. If the proxy responds, no action is taken. Displays the ping result, i.e. success or fail when try to ping.

It takes either a specific &rtp; proxy url (exactly as defined in the config file) or the keyword all as a parameter.

NOTE: When specify the IPv6 &rtp; proxy url one must prefix it with :: to escape the :: from the IPv6 address. See the example below.

#### `rtpengine.ping` usage

    ...
    $ &kamctl; rpc rtpengine.ping udp:192.168.2.133:8081
    $ &kamctl; rpc rtpengine.ping ::udp6:fe80::9a90:96ff:fea8:fd99:9999
    $ &kamctl; rpc rtpengine.ping all
    ...

### `rtpengine.get_hash_total`

Print the total number of hash entries in the hash table at a given moment.

#### `rtpengine.get_hash_total` usage

    ...
    $ &kamctl; rpc rtpengine.get_hash_total
    ...

## Event routes

### `rtpengine:dtmf-event`

When defined, the module calls event_route[rtpengine:dtmf-event] when a DTMF is received.

    ...
    event_route[rtpengine:dtmf-event] {
        xlog("L_INFO", "callid: $avp(dtmf_event_callid)\n");
        xlog("L_INFO", "source_tag: $avp(dtmf_event_source_tag)\n");
        xlog("L_INFO", "timestamp: $avp(dtmf_event_timestamp)\n");
        xlog("L_INFO", "dtmf: $avp(dtmf_event)\n");
    }
    ...