B2B_LOGIC module
Admin Guide
Section titled “Admin Guide”Overview
Section titled “Overview”The B2BUA implementation in OpenSIPS is separated in two layers:
- a lower one(coded in b2b_entities module)- which implements the basic functions of a UAS and UAC
- an upper one - which represents the logic engine of B2BUA, responsible of actually implementing the B2BUA services using the functions offered by the low level.
This module is a B2BUA upper level implementation that can be used with b2b_entities module to have B2BUA that can be configured to provide some PBX services. The B2B services are coded in an XML scenario document. The b2b_logic module examines this document and uses the functions provided by the b2b_entities module to achieve the actions specified in the document and enable the service.
A scenario can be instantiated in two ways:
- from the script - at the receipt of a initial message
- with a extern command (MI) command - the server will connect two end points in a session(Third Party Call Control).
Dependencies
Section titled “Dependencies”OpenSIPS Modules
Section titled “OpenSIPS Modules”- b2b_entities, a db module
External Libraries or Applications
Section titled “External Libraries or Applications”The following libraries or applications must be installed before running OpenSIPS with this module loaded:
- libxml2-dev
Exported Parameters
Section titled “Exported Parameters”hash_size (int)
Section titled “hash_size (int)”The size of the hash table that stores the scenario instatiation entities.
Default value is “9” (512 records).
...modparam("b2b_logic", "hash_size", 10)...script_scenario (str)
Section titled “script_scenario (str)”This parameter should be set with the path of a document that contains a scenario that can be instantiated from the script at the receipt of an initial message.
This parameter can be set more than once.
...modparam("b2b_logic", "script_scenario", "/usr/local/opensips/scripts/b2b_prepaid.xml")...extern_scenario (str)
Section titled “extern_scenario (str)”This parameter should be set with the path of a document that contains a scenario that can be instantiated with an MI command.
This parameter can be set more than once.
...modparam("b2b_logic", "extern_scenario", "/usr/local/opensips/scripts/b2b_marketing.xml")...cleanup_period (int)
Section titled “cleanup_period (int)”The time interval at which to search for an hanged b2b context. A scenario is considered expired if the duration of a session exceeds the lifetime specified in the scenario. At that moment, BYE is sent in all the dialogs from that context and the context is deleted.
Default value is “100”.
...modparam("b2b_logic", "cleanup_period", 60)...custom_headers (str)
Section titled “custom_headers (str)”A list of SIP header names delimited by ’;’ that should be passed from the dialog of one side to the other side. There are a number of headers that are passed by default. They are:
- Max-Forwards (it is decreased by 1)
- Content-Type
- Supported
- Allow
- Proxy-Require
- Session-Expires
- Min-SE
- Require
- RSeq
If you wish some other headers to be passed also you should define them by setting this parameter.
Default value is “NULL”.
...modparam("b2b_logic", "custom_headers", "User-Agent;Date")...use_init_sdp (int)
Section titled “use_init_sdp (int)”This parameter modifies the behaviour of the B2BUA when bridging and a provisional media uri is set. For playing media while the callee answers (that is connecting the caller to a media server), the bridging with the callee must start by sending an Invite to it. The correct way is to send an Invite without a body in this case, but it has been observed that not many gateways support this. So, the solution is to use the sdp received in the first Invite from the caller and put it as the body for this invite. By setting this parameter, this behavior is enabled.
Default value is “0”.
...modparam("b2b_logic", "use_init_sdp", 1)...server_address (str)
Section titled “server_address (str)”The IP address of the machine that will be used as Contact in the generated messages. This is compulsory only when using external scenarios. For the script scenarios, if it is not set, it is constructed dynamically from the socket where the initiating request was received. This socket will be used to send all the requests, replies for that scenario instantiation.
...modparam("b2b_logic", "server_address", "sip:sa@10.10.10.10:5060")...init_callid_hdr (str)
Section titled “init_callid_hdr (str)”The module offers the possibility to insert the original callid in a header in the generated Invites. If you want this, set this parameter to the name of the header in which to insert the original callid.
...modparam("b2b_logic", "init_callid_hdr", "Init-CallID")...Exported Functions
Section titled “Exported Functions”b2b_init_request
Section titled “b2b_init_request”This is the function that must be called by the script writer on an initial INVITE for which a B2B scenario must be instantiated. It is up to the script writer to decide which are the criteria to decide for which messages certain scenarios must be instantiated. The first parameter is the identifier for the scenario. This is defined in the XML document as an attribute of the root node. Then it can take at most 4 other parameters that represent the parameters for the xml scenario. The expected number of parameters is also specified as an attribute in the root node of the XML scenario.
...if(is_method("INVITE") && !has_totag() && prepaid_user()) b2b_init_request("prepaid", "sip:320@opensips.org:5070", "sip:321@opensips.org:5070"));...Exported MI Functions
Section titled “Exported MI Functions”b2b_trigger_scenario
Section titled “b2b_trigger_scenario”This command instantiated a B2B scenario.
Name: b2b_trigger_scenario
Parameters:
- senario_id : the id of the scenario to be instantiated.
- scenario parameters - it can take 4 more parameters that are scenario parameters
MI FIFO Command Format:
:b2b_trigger_scenario:fifo_reply marketing sip:bob@opensips.org sip:322@opensips.org:5070 sip:alice@opensips.org _empty_line_b2b_bridge
Section titled “b2b_bridge”This command can be used by an external application to tell B2BUA to bridge a call party from an on going dialog to another destination. By default the caller is bridged to the new uri and BYE is set to the callee. You can instead bridge the callee if you send 1 as the third parameter.
Name: b2b_trigger_scenario
Parameters:
- dialog-id : the id of the dialog. If you set the module parameter dialog-id the server will include the dialogid in the generated Invites as the content of a header with name ‘Dialog-ID’.
- new uri - the uri of the new destination
- flag to specify that the callee must be bridged to the new destination. It is optional. If not present the caller will be bridged.
MI FIFO Command Format:
opensipsctl fifo b2b_bridge 1020.30 sip:alice@opensips.orgContributors
Section titled “Contributors”By Commit Statistics
Section titled “By Commit Statistics”Top contributors by DevScore(1), authored commits(2) and lines added/removed(3)
| # | Name | DevScore | Commits | Lines++ | Lines— |
|---|---|---|---|---|---|
| 1. | Stefan Darius (@dariusstefan) | 11 | 5 | 388 | 63 |
| 2. | Razvan Crainea (@razvancrainea) | 3 | 1 | 2 | 2 |
(1) DevScore = author_commits + author_lines_added / (project_lines_added / project_commits) + author_lines_deleted / (project_lines_deleted / project_commits)
(2) including any documentation-related commits, excluding merge commits
(3) ignoring whitespace edits, renamed files and auto-generated files
By Commit Activity
Section titled “By Commit Activity”| # | Name | Commit Activity |
|---|---|---|
| 1. | Stefan Darius (@dariusstefan) | Jun 2026 - Jul 2026 |
| 2. | Razvan Crainea (@razvancrainea) | Jun 2026 - Jun 2026 |
(1) including any documentation-related commits, excluding merge commits
Documentation
Section titled “Documentation”Contributors
Section titled “Contributors”Last edited by: Razvan Crainea (@razvancrainea).
License
Section titled “License”All documentation files (i.e. .md extension) are licensed under the Creative Common License 4.0