ProSBC Configuration for Robocall Mitigation with Transnexus ClearIP service
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: https://docs.telcobridges.com/tbwiki/ProSBC:CNAM_Verification_Robocall_Analytics
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
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
- 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_Robo' 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.
Configure Transport Server for ClearIP NAP
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)
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: https://docs.telcobridges.com/tbwiki/Toolpack:Creating_a_First_Call_Route_E
It could also combine with other Routeset routing: https://docs.telcobridges.com/tbwiki/Toolpack:Tsbc_Call_Routes_Settings_3.1#Label_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
- The default route retry action of 404 is Stop call.
- The default route retry action of 603 is Continue call.