Securing calls over SRTP

Last Updated : Sep 29, 2022 |

Before you begin

To secure the customer and agent nailup calls, the media has to be sent over SRTP. For this, MPP provides use_protocols hints that can be used by the CCXML applications when launching the calls.

Use this procedure to configure the protocols to be used for call launch or SIP invite.

The following table provides the format in which you can specify the protocols in the Protocols and their Order to try for a call field:

Value

Description

sips,sip

This is the default value using which calls are launched over SIPS first. In case of failure, calls are retried over SIP.

*sips,sip

This enforces any tel or SIP URI to be converted into SIPS.

Procedure

  1. Configure VOIP connection with TLS and SRTP enabled.
  2. Stop the POM service.
  3. Log on to the POM Administration Portal.
  4. In the navigation pane, click Proactive Outreach > Manager.
  5. On the Configurations menu, click Global Configurations.
  6. On the Global Configurations page, click the Advanced Settings tab.
  7. In the Advance Settings area, in the Protocols and their Order to try for a call field, specify the comma separated list of protocols.
  8. Start the POM service.
  9. Launch the POM campaigns and trace the SIP flows.
  10. Verify the outbound INVITE.

    The SDP offer must contain SRTP.

    Note:

    In case of Invite failures, MPP SIP stack does a retry for certain SIP 4xx-client failure responses which are defined by retry_sips hints in CCXML. You can configure this hint in the POM database in the pim_config table. This hint is used for all customer and agent calls launched from the POM CCXML applications. With the default setting retry_sips=488, only a 488 SIP response is retried. This setting accepts the value true or a comma separated list of SIP response codes to retry. For example, retry_sips=488,485,483. The setting of true uses a default list of retry response codes, which currently consists of any SIP response greater than or equal to 480. However, this is not recommended as POM ends up retrying on 486:Busy Here SIP response code.