Back to back UserAgent (b2b)

Table of Contents

Description
Parameters
Configuration example
See also

Description

A role that organizes switching between SIP devices by creating two-way dialogs.
Performs routing and calling of relevant devices with media flow organization between them via roles mgc and mg.

Reserved and scaled in mode Active-Active.

Services:
- Organization and maintenance of SIP-dialogs
- Managing the business logic of media context.
- Routing in the internal numbering plan.
- Calculation of subscriber representation.
- Forking (calling multiple registered devices or in multiple directions).
- Subscriber features: call forwarding, group number, intercept, intercom, intrusion, transfer, shoulder swap, multiple call….
- Chief-Secretary type groups.
- CDR Event Generation.
- Authorization of SIP calls.
- Maintenance of registrations.
- Maintenance of subscriptions (BLF, voicemail) and sending notifications.
- SIP service balancer.
- …

Table 1. System Characteristics

Code	`b2b`
Mode of operation	`Service`
Backup mode	`Active-Active`
Types of sites	`Any`
Layer	`Business logic`
Placement	`Internal`
Saving and restoring state on reboot	`No`
appendix	`era_sip`

Parameters

Description of columns in the table

Table 2. Parameters
Name	Type	Default	Description
`name`	`str`	required	Name. May consist of Latin letters and numbers, must begin with a letter.
`roletype`	`str`	required	Role Type. Possible values: `"b2b"`.
`iface`	`str`	required	The alias of the server network interface on which the roles will interact internally with each other.
`ext`	`json`	empty	Additional role options. Contains a json object or list.
`enabled`	`bool`	empty	Role activity flag. When set to false, the role does not participate in validation and is not started.
`roleid`	`int`	required	Role ID. Unique for the entire system, regardless of the site or server. Cannot be changed. Integer from `1` to `9999`.
`separate`	`bool`	required	An indication that the role has been allocated to a separate node.
`udp`	`int`	required	Local UDP port for SIP. The same port handles both TCP. For example: `5090`. Used for internal communication with other microservices of the system via protocol SIP. Raised only on the local interface to which the node is bound. Should not be used by other microservices executing on the same server.
`tcp`	`int`	required	Local TCP port for SIP. If a value other than UDP is specified, it will be raised additionally. For example: `5090`. Used for internal communication with other microservices of the system via protocol SIP. Raised only on the local interface to which the node is bound. Should not be used by other microservices executing on the same server.
`log_cdr`	`bool`	`true`	Switch for logging events to log `cdr`.
`log_media`	`bool`	`true`	Media function logging switch `media`.
`log_mgct`	`bool`	`true`	Switch for logging the communication protocol with the MGC controller to the logger `mgct`.
`log_sip`	`bool`	`true`	Switch for logging dialog state machine trace to logs `sip`.
`log_trn`	`bool`	`true`	SIP traffic logging switch to log `trn`.
`use_srtp`	`bool`	`false`	By default, SDP-offer for unencrypted media stream (rtp) is sent to TLS-connected addresses when initiating calls. You can use the parameter to enable SDP-offer initiation with encrypted media stream for TLS addresses.
`allow_ac_set`	`bool`	`true`	Codec set sending mode switch in responses to INVITE. `false` – no more than one codec is sent in the response from the codecs received in the Offer SDP. `true` – a subset of codecs from the list of codecs received in the Offer SDP.
`save_rtp_stat`	`bool`	`false`	Place statistics on RTP packets in the call termination event
`send_reinvite_on_ack`	`bool`	`false`	Switch for sending re-INVITE to the call initiator immediately after the dialog is established (SIP confirmation request received) ACK). Can be used to update the data on the display in case the devices do not process the SIP header `Remote-Party-Id`. It can also be used to align codecs to increase the probability of direct traffic transmission without transcoding.
`check_by_options_on_limit`	`bool`	`false`	Switches the device verification mode by sending SIP request OPTIONS when a REGISTER request exceeding the license limit is received. `false` – deregister; `true` – check the availability of registered devices, and if unavailability is detected, automatically replace the registration.
`payloads_audio_offer`	`array<str>`	`["PCMA/8000", "PCMU/8000","telephone-event/8000"]`	List of audio codec names used for call initiation (shoulder call). As value - a list containing names of audio codecs in format `"Name/Freq"`. The following codecs are supported (case-sensitive): `telephone-event/8000`, `PCMU/8000`, `PCMA/8000`, `GSM/8000`, `G722/8000`, `G729/8000`, `CN/8000`, `speex/8000`, `speex/16000`, `speex/32000`, `G726-16/8000`, `G726-24/8000`, `G726-32/8000`, `G726-40/8000`, `iLBC/8000`, `opus/48000/2`. The three basic formats, `PCMA/8000`, `PCMU/8000` and `telephone-event/8000` are automatically added to initiated calls at any field value.
`payloads_video_offer`	`array<str>`	empty	List of video codec names used to initiate a call (shoulder call). As a value - a list containing video codec names in the following format `"Name/Freq"`. The following codecs are supported (case-sensitive): `H263/90000`, `H263-1998/90000`, `H264/90000`, `VP8/90000`, `VP9/90000`.
`use_video_transcoding`	`bool`	`false`	Utilize video transcoding. `false` – all video codecs from the SDP INVITE request received from the initiator are translated unchanged into SDP INVITE requests to the called devices. In this case, the system does not apply either its knowledge of codecs or transcoding, and the codec is unknown to the system, direct transfer is nevertheless still possible. `true` – all video codecs are listed according to the video codecs known to the system, the system offers all known codecs to the called party (with a filter from payloads_video_offer), and if the codecs selected by the devices do not match, transcoding is performed on the video stream.
`record_ivr`	`bool`	`false`	Dialog recording switch with IVR. When `false` is specified, media traffic of calls in the IVR, including queues, is not forcibly recorded, regardless of the settings of recording rules.
`record_conf`	`bool`	`false`	Conference dialog recording switch. When `false` is specified, media traffic on conference room calls is not forcibly recorded, regardless of the settings of the recording rules.
`record_prompt`	`bool`	`false`	A switch to record eavesdropping and prompter dialogs. When `false` is specified, media traffic of eavesdropping and suffocation calls is not forcibly recorded, regardless of the settings of recording rules.
`fwd_headers`	`array<object>`	empty	Headline Trolling. B2B serves calls in such a way that a separate shoulder is created for each participant with a unique Call-ID. When forming an outgoing INVITE request B2B by default does not add custom headers from the incoming INVITE request. To ensure that certain custom headers from an incoming INVITE request are added to the outgoing INVITE request, a list of their names must be provided. Format: `["X-Header-1", "header-2", ...]` The default is blank.
`local_mg_lower_priority`	`bool`	true	Switch to downgrade the priority of local MG media gateways located on the same server as the currently active signaling server. During shutdown, local media gateways participate equally with other media gateways. Enabled by default - local media gateways are used only if no other media gateways are found capable of serving the new context. It is used in multi-server systems to preferentially disperse the responsibility for handling a call across different servers. If a media gateway server serving media traffic goes down, the conversation can be saved only if all servers serving call signaling remain available.

Configuration example

The configuration is managed in an application available to master domain administrators. The application hides the full content of the configuration, but it is nevertheless accessible via the API.

The configuration contains a section to describe all instances of all roles. Parameters are defined for each specific role instance.

Example node

{
    "name": "b2b1",
    "roletype": "b2b",
    "iface": "eth0",

    "roleid": 11240,
    "separate": true,
    "udp": 5090,
    "tcp": 5090,

    "send_reinvite_on_ack": false,
    "allow_ac_set": false,
    "check_by_options_on_limit": true,
    "record_conf": false,
    "record_ivr": false,

    "log_cdr": true,
    "log_trn": true,
    "log_sip": true,
    "log_media": true,
    "log_mgct": true,

    "fwd_headers": [
        "X-Header-1",
        "X-Header-2"
    ],

    "payloads_audio_offer": [
        "PCMU/8000", "CN/8000", "G722/8000"
    ]
 }

Back to back UserAgent (b2b)

Description

Parameters

Configuration example

See also