This document provides instructions on how to configure ProSBC to operate with the TransNexus ClearIP server for Robocall Mitigation. ClearIP is a SIP redirect server that provides advanced Least Cost Routing (LCR), fraud control and STIR (Secure Telephony Identity Revisited) / SHAKEN (Secure Handling of Asserted information using toKENs) features.
ProSBC 3.0.90 or a later version is needed to support Robocall Mitigation with TransNexus.
For CNAM Verification and Robocall Analytics, please check the instruction here.
Typical Call Scenarios
This section provides the simplified network diagram with typical call flows.
1. Source of ServiceProvider sends a call to ProSBC.
2. ProSBC forwards the call to ClearIP for Robocall Mitigation process
3. ClearIP analyzes the call for robocall mitigation and toll fraud, then sends one of the following responses to ProSBC
3a.SIP 404 Not Found: No fraud is detected, not a robocall.
3b.SIP 503 Service unavailable: No fraud is detected, not a robocall.
4c. SIP 603 Decline: Fraud is detected, block the call.
4. Upon receiving 404 or 503
4a: - ProSBC returns SIP 503 (or mapping to the TDM cause code) to the Source switch to perform route advance
Call Source (TDM or SIP) --------Invite or SETUP or IAM ---------> ProSBC ----Invite--> ClearIP
Call Source (TDM or SIP) <---SIP 503 or REL with 41 or 34 -------- ProSBC < ----503---- ClearIP
4b: - ProSBC route advances on SIP 503 and sends call to next destination, does not return response to the Source switch
Call Source (TDM or SIP) ---Invite or SETUP or IAM ---> ProSBC ----Invite--> ClearIP
ProSBC < ----503---- ClearIP
ProSBC ----Invite---Next Routes
Upon receiving 603
4c: ProSBC returns SIP 603 (or mapping to the TDM cause code) to the Source switch, then release the call
Call Source (TDM or SIP) -----Invite or SETUP or IAM ------> ProSBC ----Invite--> ClearIP
Call Source (TDM or SIP) <---SIP 603 or REL with 21 -------- ProSBC < ----603---- ClearIP
ProSBC Configuration
This section provides ProSBC configuration for the solution.
Configure Routing Script
ProSBC is configured to use routing script to send some SIP headers to ClearIP to identify the source of the call.
1. Enable routing script
Gateway->Use script
2. Load routing scripts
Gateway->Routes->Routing Script->Import Script File
File->ClearIP_Query.rb
ScriptType->filter
Load on startup->checked
Gateway->Routes->Routing Script->Edit the main script:
- Add the "require 'ClearIP_Query' unless defined?(ClearIPQuery)" statement at the top of the main script.
- Add the "include ClearIPQuery" statement in the main routing class.
- Add the filter " before_filter :method => :ClearIP_query" in the main routing class.
SIP -> Create New Transport Server
Name->TS_TCP_5060
Port Type->TCP
Port->5060
IP Interface-> Select the IP interface which can reach to ClearIP on the public network
Configure ClearIP NAP
NAPs->Create New NAP
Name->NAP_CLEARIP
Proxy address->sip.clearip.com (FQDN of ClearIP-A)
Configure Routes
You need to configure other routes after the ClearIP routes if you want ProSBC to perform route advances.
Check the below link for the detail instruction to create static routes:
It could also combine with other Routeset routing:
Configure Route Retry Action
Route retry action of 3xx, 404 and 603 must be configured to allow ProSBC to perform failover, fraud control and SHAKEN AS/VS request.
Profiles->Edit Reason Cause Mapping
404 Not found->Route retry action->Continue call
503 Service unavailable->Route retry action->Continue call
603 Decline->Route retry action->Stop call
Notes:
The default route retry action of 404 is Stop call.
The default route retry action of 603 is Continue call.
