CALL-CENTER module

Admin Guide

Overview

The Call Center module implements an inbound call center system with call flows (for queuing the received calls) and agents (for answering the calls).

The module implements the queuing system, the call distribution to agents, agents managements, CDRs for the calls, statistics on call distribution and agent’s activity - basically everything except the media playback (for the queue). This part must be provided via a third party media server (FreeSwitch, Asterisk or others).

This is actually a Contact Center and it is able to handle both RTP/audio calls and (multiple) MSRP/chat calls, in the same time.

The module provides an internal buit-in dispatching logic (for sending the calls/chats to the agents), but also offers the possibility to use an external logic to do the dispatching (see mi dispatch call to agent MI command).

How it works

The main entities in the modules are the flows (queues) and agents.

DB tables

Each entity has a corresponding table in the database, for provisioning purposes - the cc_flows and cc_agents tables, see DB schema. Data is loaded at startup and cached into memory ; runtime reload is possible via the MI commands (see the call_center:reload command in exported mi functions).

Additionally there is a table cc_cdrs for writing the CDRs - this operation is done in realtime, after the call in completed, covering all possible cases: call was dropped while in queue, call was rejected by agent, call was accepted by agent, call terminated with error - NOTE that a call may generate more than one CDR (like call rejected by agent A, and redistributed and accepted by agent B).

The cc_calls table is used to store ongoing calls, regardless it’s state (in queue, to the agent, ended). It is populated at runtime by the module and queried at startup. This table should not be manually provisioned.

Call Flows

A flow is defined by a unique alphanumerical ID - the main attribute of a flow is the skill - the skill is a capability required by the flow for an agent to be able to answer the call ; the concept of skills is the link between the flows and the agents - telling what agents are serving what flows - the flows require a skill, while the agents provide a set of skills. Agents matching the required skill of a flow will automatically receive calls from that flow.

Additional, the flow has a priority - as agents may server multiple flows in the same time (based on skills), you can define priorities between the flows - if the flows has a higher priority, its calls will be pushed (in deliver to agents and queuing) in front of the calls from flows with a lower priority.

Configurable per flow, the module may do per-flow call dissuading; this means to redirect a call to another destination, if the queue/flow is overloaded:

if the number of calls already in the queue exceeds the diss_qsize_th threshold
if the estimated time to wait of the queue exceeds the diss_ewt_th threshold
if the call was waiting in the queue for longer than diss_onhold_th threshold

Optionally, the flow may define a prependcid - a prefix to be added to the CLI (Caller ID) when the call is delivered to the agents - as an agent may receive call from multiple flows, it is important for the user to see which was the queue a call was received.

In terms of media announcements, the flow defines the message_welcome (optional, to be played in the call, before doing anything with the call) and message_queue (mandatory, the looping message providing infinite on hold media IMPORTANT - this message must cycle and media server must never hung up on it. Both announcements are provided as SIP URIs (where the call has to be sent in order to get the playback).

The flow also has an optional max_wrapup time, which acts as an upper limit for the per-agent/global value (the flow forces a ceiling of the wrapup value for all its calls).

Agents

An agent is defined by a unique alphanumerical ID - the main attribute of an agent is its the set of skills. This set of skills will tell what calls to be received (from which flows, based on the skill matching).

The agent may provide support for different optional media types, like RTP/audio or MSRP/chat. Each supported media type comes with the maximum supported number of sessions. Of course, for audio the 1 value is hardocded. On the SIP side, each media type comes with a locations. The location is a SIP URI where to calls must be sent in order to be answered by the agent. At least one media type should be defined. To specify which media the agent support, just define the corresponding SIP location in his profile.

So, at a certain time, an agent may handle either a single call, either several chat sessions.

Additionally, the agent has a initial logstate - if he is logged in or not (being logged in is a must in order to receive calls). The log state may be changed at runtime via a dedicated MI command call_center:agent_login, see exported mi functions.

There is an optional per-agent wrapup_time defined, saying the time interval for an agent before getting a new call from the system (after he finished a call). If no value is defined for the agent, the global wrapup_time will be used. Note that the resulting value may be upper limited by the per-flow max_wrapup_time if defined.

Dependencies

OpenSIPS Modules

The following modules must be loaded before this module:

b2b_logic - B2bUA module
database - one of the SQL DB modules

External Libraries or Applications

The following libraries or applications must be installed before running OpenSIPS with this module loaded:

None.

Exported Parameters

db_url (string)

SQL address to the DB server — database specific. This must be the Database holding the provisioning tables (cc_flows, cc_agents and cc_calls tables).

...
modparam("call_center", "db_url",
  "mysql://opensips:opensipsrw@localhost/opensips")
...

acc_db_url (string)

SQL address to the DB server — database specific. This must be the Database where the CDRs table (cc_cdrs) is located.

...
modparam("call_center", "acc_db_url",
  "mysql://opensips:opensipsrw@localhost/opensips_cdrs")
...

rt_db_url (string)

SQL address/URL of the DB server (database specific) where the runtime tables (non provisioning tables) are located. The runtime tables are the tables populated by OpenSIPS with data learned during runtime. To be more specific, the only runtime table we have so far is the “cc_calls” table.

...
modparam("call_center", "rt_db_url",
  "mysql://opensips:opensipsrw@localhost/opensips_runtime")
...

wrapup_time (integer)

Time for an agent between finishing a call and receiving the next call from the system. Even if there are queued calls, the module will not deliver call to agent during this wrapup interval.

This value may be overwritten by the per-agent value (if defined) and furher more, by the per-flow value (if defined).

Default value is “30 seconds”.

...
modparam("call_center", "wrapup_time", 45)
...

queue_pos_param (string)

The name of an SIP URI parameter to be used to report the position in the waiting queue when sending the call to media server for onwait/queue playback. The position 0 means it is the next call to be delivered to an agent.

Default value is “empty(none)“.

...
modparam("call_center", "queue_pos_param", "cc_pos")
...

reject_on_no_agents (int)

A parameter to tell if an incoming call should be rejected or quueued if there are no logged in agents. Basically this allows call queueing on flows with no agents yet.

Default value is “1 (true)“.

...
modparam("call_center", "reject_on_no_agents", 0)
...

chat_dispatch_policy (int)

A parameter to tell what should be the policy on dispatching the chat/MSRP sessions to the agents, considering that an agent may handle multiple such sessions/chats in the same time.

Options are:

balancing - the distribution will try to be even across the agents, but by doing this you may end up waisting chat sessions on agents and call starvation - agents are partially used by chat sessions, so they cannot take calls (of course, if you have mixed agetns with audio/chat)
full-load - the distribution will try to make usage of an agent in the best possible way when comes to chat sessions - once the agent take a chat, all the following chats will be assigned ot him - the idea is to try to be efficient in using the resource/sessions of an agents, to leave as much room as possible for calls. Of course, this may lead to an un-even loading of chat agents - some will be full, others empty.

Default value is “balancing”.

...
modparam("call_center", "chat_dispatch_policy", "balancing")
...

internal_call_dispatching (int)

A parameter to tell if the internal/buit-in call dispatching to agent should be used or not. If enabled, the module will automatically dispatch (by itself) the queued/incoming calls to the available agents. If disabled, the module will not do such dispaching by itself and it is expected to use the mi dispatch call to agent MI command to dispatch the queued calls to agents. This allows the implementation of an external, custom dispatching logic. The value of this setting may be changed during runtime via the mi internal call dispatching MI command.

Default value is “1” (enabled).

...
modparam("call_center", "internal_call_dispatching", 0)
...

cc_agents_table (string)

Name to be used for the table holding the agents.

Default value is “cc_agents”.

...
modparam("call_center", "cc_agents_table", "my_agents")
...

cca_agentid_column (string)

Name to be used for the “agent id” (unique DB id) column in the agents table.

Default value is “agentid”.

...
modparam("call_center", "cca_agentid_column", "cid")
...

cca_location_column (string)

Name to be used for the calling/audio “location” (SIP URI) column in the agents table.

Default value is “location”.

...
modparam("call_center", "cca_location_column", "sip_uri")
...

cca_msrp_location_column (string)

Name to be used for the msrp/chat “location” (SIP URI) column in the agents table.

Default value is “msrp_location”.

...
modparam("call_center", "cca_msrp_location_column", "sip_uri")
...

cca_msrp_max_sessions_column (string)

Name to be used for the column (in the agents table) holding the maximum number of chat sessions that can be handled by the agent.

Default value is “msrp_max_sessions”.

...
modparam("call_center", "cca_msrp_max_sessions_column", "max_chats")
...

cca_skills_column (string)

Name to be used for the “skills” (list of skills) column in the agents table.

Default value is “skills”.

...
modparam("call_center", "cca_skills_column", "skills")
...

cca_logstate_column (string)

Name to be used for the “logstate” (original login state) column in the agents table.

Default value is “logstate”.

...
modparam("call_center", "cca_logstate_column", "log_state")
...

cca_wrapuptime_column (string)

Name to be used for the “wrapuptime” (per-agent wrapup time) column in the agents table.

Default value is “wrapup_time”.

...
modparam("call_center", "cca_wrapuptime_column", "wtime")
...

cca_wrapupend_column (string)

Name to be used for the “wrapupend” (timestamp when the wrapup ends) column in the agents table.

Default value is “wrapup_end_time”.

...
modparam("call_center", "cca_wrapupend_column", "wrapup_ends")
...

cc_flows_table (string)

Name to be used for the table holding the definition of the flows/queues.

Default value is “cc_flows”.

...
modparam("call_center", "cc_flows_table", "queues")
...

ccf_flowid_column (string)

Name to be used for the “flow id” (unique DB id) column in the flows table.

Default value is “flowid”.

...
modparam("call_center", "ccf_flowid_column", "queue_id")
...

ccf_priority_column (string)

Name to be used for the “priority” column in the flows table.

Default value is “priority”.

...
modparam("call_center", "ccf_priority_column", "queue_prio")
...

ccf_skill_column (string)

Name to be used for the “skill” column in the flows table.

Default value is “skill”.

...
modparam("call_center", "ccf_skill_column", "queue_skill")
...

ccf_cid_column (string)

Name to be used for the “caller ID prefix” column in the flows table.

Default value is “prependcid”.

...
modparam("call_center", "ccf_cid_column", "queue_cli_prefix")
...

ccf_max_wrapup_column (string)

Name to be used for the “max limit for wrapup time” column in the flows table.

Default value is “max_wrapup_time”.

...
modparam("call_center", "ccf_max_wrapup_column", "queue_wrapup")
...

ccf_dissuading_hangup_column (string)

Name to be used for the “hangup after dissuading” column in the flows table.

Default value is “dissuading_hangup”.

...
modparam("call_center", "ccf_dissuading_hangup_column", "hangup_on_dissuading")
...

ccf_dissuading_onhold_th_column (string)

Name to be used for the “on-hold dissuading threshold” column in the flows table.

Default value is “dissuading_onhold_th”.

...
modparam("call_center", "ccf_dissuading_onhold_th_column", "th_diss_onhold")
...

ccf_dissuading_ewt_th_column (string)

Name to be used for the “EWT dissuading threshold” column in the flows table.

Default value is “dissuading_ewt_th”.

...
modparam("call_center", "ccf_dissuading_ewt_th_column", "th_diss_ewt")
...

ccf_dissuading_qsize_th_column (string)

Name to be used for the “queue size dissuading threshold” column in the flows table.

Default value is “dissuading_qsize_th”.

...
modparam("call_center", "ccf_dissuading_qsize_th_column", "th_diss_qsize")
...

ccf_m_welcome_column (string)

Name to be used for the “audio message on welcome” column in the flows table.

Default value is “message_welcome”.

...
modparam("call_center", "ccf_m_welcome_column", "audio_welcome")
...

ccf_m_queue_column (string)

Name to be used for the “audio message on queueing” column in the flows table.

Default value is “message_queue”.

...
modparam("call_center", "ccf_m_queue_column", "audio_queue")
...

ccf_m_dissuading_column (string)

Name to be used for the “audio message on dissuading” column in the flows table.

Default value is “message_dissuading”.

...
modparam("call_center", "ccf_m_dissuading_column", "audio_dissuading")
...

ccf_m_flow_id_column (string)

Name to be used for the “audio message on identifying the flow” column in the flows table.

Default value is “message_flow_id”.

...
modparam("call_center", "ccf_m_flow_id_column", "audio_flow_id")
...

b2b_logic_ctx_param (string)

The name of the $b2b_logic.ctx variable that can be used to retrieve the value of the parameter passed to the cc handle call function.

This parameter will be copied throughout all the B2B scenarios started by the call_center module. NOTE that you can change the value of the current scenario by writing into it, but the change will not be reflected in a different scenario.

Default value is “call_center”.

...
modparam("call_center", "b2b_logic_ctx_param", "b2b_callid")
...
route[handle_call_center] {
    ...
    cc_handle_call("flow", $ci);
    ...
}
...
route[b2b_handle_request] {
    ...
    xlog("Initial Callid is $b2b_logic.ctx(b2b_callid)\n");
    ...
}

Exported Functions

cc_handle_call( flowID [,param])

This must be used only for initial INVITE requests - the function pushes the call to be handled by the call center module (via a certain flow/queue).

This function can be used from REQUEST_ROUTE.

Parameters:

flowID (string) - the ID of the flow to handle this call (push the call to that flow).
param (string, optional) - an opaque string to be passed as parameter to the “callcenter” and “agent” B2B scenarios. It is intended for custom integration of the call center module and it is 100% up to the script writer about the value and purpose of this parameter, OpenSIPS will not touch or interpret it. You can retrieve the value of this parameter using the $b2b_logic.ctx variable with the name defined in the b2b logic ctx param parameter.

The function returns TRUE back to the script if the call was successfully pushed and handled by the Call Center engine. IMPORTANT: you must not do any signaling on the call (reply, relay) after this point.

In case of error, FALSE is returned to the script with the following return codes:

-1 - unable to get the flow ID from the parameter;
-2 - unable to parse the FROM URI;
-3 - flow with FlowID not found;
-4 - no agents logged in the flow;
-5 - internal error;

...
if (is_method("INVITE") and !has_totag()) {
  if (!cc_handle_call("tech_support")) {
    send_reply(403,"Cannot handle call");
    exit;
  }
}
...

cc_agent_login(agentID, state)

This function sets the login (on or off) state for an agent.

This function can be used from REQUEST_ROUTE.

Parameters:

agentID (string) - the ID of the agent
state (int) - an integer value giving the new state - 0 means logged off, anything else means logged in.

...
# log off the 'agentX' agent
cc_agent_login("agentX",0);
...

Exported Statistics

Global statistics

ccg_incalls

Total number of received calls. (counter type)

ccg_awt

Global avg. waiting time for calls. (realtime type)

ccg_load

Global load (across all flows). (realtime type)

ccg_distributed_incalls

Total number of distributed calls. (counter type)

ccg_answered_incalls

Total number of calls (audio/RTP and chat/MSRP) answered by agents. (counter type)

ccg_answered_inchats

Total number of chat/MSRP only calls answered by agents. (counter type)

ccg_abandonned_incalls

Total number of calls terminated by caller before being answered by agents. (counter type)

ccg_onhold_calls

Total number of calls (audio/RTP and chat/MSRP) in the queues (onhold). (realtime type)

ccg_onhold_chats

Total number of chat/MSRP only calls in the queues (onhold). (realtime type)

ccg_free_agents

Total number of free agents (across all flows). (realtime type)

Per-flow statistics (one set for each flow)

ccf_incalls_flowID

Number of received calls for the flow. (counter type)

ccf_dist_incalls_flowID

Number of distributed calls in this flow. (counter type)

ccf_answ_incalls_flowID

Nnumber of calls (audio/RTP and chat/MSRP) from the flow answered by agents. (counter type)

ccf_answ_incalls_flowID

Nnumber of chat/MSRP only calls from the flow answered by agents. (counter type)

ccf_aban_incalls_flowID

Number of calls (from the flow) terminated by caller before being answered by agents. (counter type)

ccf_onhold_incalls_flowID

Number of calls (audio/RTP and chat/MSRP) -from the flow- which are onhold. (realtime type)

ccf_onhold_inchats_flowID

Number of chat/MSRP only calls -from the flow- which are onhold. (realtime type)

ccf_queued_calls_flowID

Number of calls which are queued for this flow. (realtime type)

ccf_free_agents_flowID

Number of free agents serving this flow. (realtime type)

ccf_etw_flowID

Estimated Time to Wait for this flow. (realtime type)

ccf_awt_flowID

Avg. Wating Time for this flow. (realtime type)

ccg_load_flowID

The load on the flow (number of queued calls versus number of logged agents). (realtime type)

Per-agent statistics (one set for each agent)

cca_dist_incalls_agnetID

Number of distributed calls to this agent. (counter type)

cca_answ_incalls_agentID

Number of calls (audio/RTP and chat/MSRP) answered by the agent. (counter type)

cca_answ_inchats_agentID

Number of chat/MSRP only calls answered by the agent. (counter type)

cca_aban_incalls_agentID

Number of calls (sent to this agent) terminated by caller before being answered by agents. (counter type)

cca_att_agentID

Avg. Talk Time for this agent (realtime type)

Exported MI Functions

call_center:reload

Replaces obsolete MI command: cc_reload.

Command to reload flows and agents definition from database.

It takes no parameter.

MI FIFO Command usage:

opensips-cli -x mi call_center:reload

call_center:agent_login

Replaces obsolete MI command: cc_agent_login.

Command to login an agent into the Call Center engine.

Parameters:

agent_id - ID of the agent
state - the new login state (0 - log off, 1 - log in)

MI FIFO Command usage:

opensips-cli -x mi call_center:agent_login agentX 0

call_center:list_queue

Replaces obsolete MI command: cc_list_queue.

Command to list all the calls in queuing - for each call, the following attributes will be printed: the call id, the calling user info, the flow of the call, for how long the call is in the queue, the ETW for the call, call priority and the call skill (inherited from the flow).

It takes no parameter.

MI FIFO Command usage:

opensips-cli -x mi call_center:list_queue

call_center:list_flows

Replaces obsolete MI command: cc_list_flows.

Command to list all the flows - for each flow, the following attributes will be printed: the flow ID, the avg. call duration, how many calls were processed, how many agents are logged, and how many onging calls are.

It takes no parameter.

MI FIFO Command usage:

opensips-cli -x mi call_center:list_flows

call_center:list_agents

Replaces obsolete MI command: cc_list_agents.

Command to list all the agents - for each agent, the following attributes will be printed: agent ID, agent login state, agent state (free, wrapup, incall) and info on ongoing sessions.

It takes no parameter.

MI FIFO Command usage:

opensips-cli -x mi call_center:list_agents

call_center:list_calls

Replaces obsolete MI command: cc_list_calls.

Command to list all the ongoing calls - for each call, the following attributes will be printed: call ID, call state (welcome, queued, toagent, ended), call duration, flow it belongs to, agent serving the call (if any).

It takes no parameter.

MI FIFO Command usage:

opensips-cli -x mi call_center:list_agents

call_center:dispatch_call_to_agent

Replaces obsolete MI command: cc_dispatch_call_to_agent.

This function sends a given call (from the queue) to a given agent. For the operation to succeed, several conditions must be met:

the call must be in the queue
the agent must be logged in
the agent must support the skill required by the call
the agent must support the media (RTP/MSRP) requiref by the call
the agent must have available sessions for the requested media

It takes two parameters.

call_id - the ID of the call, as provided by the queue listing MI command mi list queue
agent_id - the ID of the call, as provided by the agents listing MI command mi list agents

MI FIFO Command usage:

opensips-cli -x mi call_center:dispatch_call_to_agent B2B452.dee2.33 agentX

call_center:internal_call_dispatching

Replaces obsolete MI command: cc_internal_call_dispatching.

Command to inspect and/or change the internal call dispatching setting

It takes one optional parameter dispatching if the value of the setting should be changed. A 0 value means disabling the internal dispatching, a non zero means to enable it.

MI FIFO Command usage:

opensips-cli -x mi call_center:internal_call_dispatching 0

call_center:reset_stats

Replaces obsolete MI command: cc_reset_stats.

Command to reset all counter-like statistics.

It takes no parameter.

MI FIFO Command usage:

opensips-cli -x mi call_center:reset_stats

Exported Events

E_CALLCENTER_AGENT_REPORT

This event is raised when the status of an agent changes.

Parameters:

agent_id - the id of the agent.
state - the status of the agent:
- offline
- free
- incall
- wrapup
wrapup_ends - the timestamp when the wrapup state will end; published only if the state is “wrapup”
flow_id - the flow ID that delivered the call for this agent; published only if the state is “incall”

Exported Pseudo-Variables

$cc_state Returns the state of a call. Possible values returned are: welcome - the welcome message is played. dissuading1 - the first dissuading message is played. dissuading2 - the second dissuading message is played. queue - the call is in queue. preagent - the agent is being called. toagent - the agent is in call.

Frequently Asked Questions

Q: Where can I find more about OpenSIPS?

Take a look at https://opensips.org/.

Q: Where can I post a question about this module?

First at all check if your question was already answered on one of our mailing lists:

E-mails regarding any stable OpenSIPS release should be sent to users@lists.opensips.org and e-mails regarding development versions should be sent to devel@lists.opensips.org.

If you want to keep the mail private, send it to users@lists.opensips.org.

Q: How can I report a bug?

Please follow the guidelines provided at: https://github.com/OpenSIPS/opensips/issues.

Contributors

By Commit Statistics

Top contributors by DevScore⁽¹⁾, authored commits⁽²⁾ and lines added/removed⁽³⁾

#	Name	DevScore	Commits	Lines++	Lines—
1.	Bogdan-Andrei Iancu (@bogdan-iancu)	112	44	6864	595
2.	Razvan Crainea (@razvancrainea)	52	38	973	248
3.	Stefan Darius	24	5	1612	279
4.	Vlad Patrascu (@rvlad-patrascu)	18	9	306	333
5.	Liviu Chircu (@liviuchircu)	15	12	73	90
6.	Maksym Sobolyev (@sobomax)	6	4	8	13
7.	Walter Doekes (@wdoekes)	4	2	1	2
8.	Peter Lemenkov (@lemenkov)	4	2	1	1
9.	Vlad Paiu (@vladpaiu)	3	1	13	4
10.	Alexandra Titoc	3	1	4	4

All remaining contributors: Zero King (@l2dy), Dusan Klinec (@ph4r05).

(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

#	Name	Commit Activity
1.	Stefan Darius	Jun 2026 - Jul 2026
2.	Razvan Crainea (@razvancrainea)	Mar 2014 - Jun 2026
3.	Liviu Chircu (@liviuchircu)	Jun 2014 - Aug 2025
4.	Alexandra Titoc	Sep 2024 - Sep 2024
5.	Maksym Sobolyev (@sobomax)	Feb 2023 - Nov 2023
6.	Bogdan-Andrei Iancu (@bogdan-iancu)	Mar 2014 - May 2023
7.	Walter Doekes (@wdoekes)	Apr 2021 - Apr 2021
8.	Vlad Patrascu (@rvlad-patrascu)	May 2017 - Jan 2021
9.	Zero King (@l2dy)	Mar 2020 - Mar 2020
10.	Peter Lemenkov (@lemenkov)	Jun 2018 - Sep 2018

All remaining contributors: Dusan Klinec (@ph4r05), Vlad Paiu (@vladpaiu).

(1) including any documentation-related commits, excluding merge commits

Documentation

Contributors

Last edited by: Razvan Crainea (@razvancrainea), Bogdan-Andrei Iancu (@bogdan-iancu), Vlad Patrascu (@rvlad-patrascu), Zero King (@l2dy), Peter Lemenkov (@lemenkov), Liviu Chircu (@liviuchircu).

License

All documentation files (i.e. .md extension) are licensed under the Creative Common License 4.0