Configuring outbound dialing campaigns across 15 BYOC trunks in the Asia Pacific region. The predictive dialer frequently throws SIP 408 Request Timeout errors when routing through secondary carriers during failover events. The primary trunks handle the load without issue, but the secondary paths seem to drop registrations before the call leg establishes.
What is the correct way to configure trunk affinity in the outbound campaign settings to prevent these timeouts during carrier failover?
it depends, but generally trunk affinity is a telephony routing concern, not an outbound campaign setting. check your sip trunk configuration for keep-alive intervals and registration timeouts instead.
Verifying WFM-Telephony Sync: As a workforce management coordinator, I see this often when schedule adherence data doesn’t align with telephony availability. If the WFM module marks an agent as “Available” but their SIP trunk is in a failover state or hasn’t re-registered post-timeout, the outbound campaign might still attempt to route through that trunk. Ensure your schedule push includes a hard stop for agents whose primary trunks are unstable.
Adjusting Campaign Pacing: The predictive dialer calculates availability based on WFM data. If trunks are timing out, the system might be overestimating available seats. Reduce the initial call rate by 20% for campaigns using secondary carriers. This gives the SIP stack more time to handle registration re-establishment without overwhelming the gateway.
Checking Keep-Alive Intervals: While trunk affinity is telephony-specific, the WFM schedule must respect the trunk’s keep-alive window. If your agents are scheduled for long shifts but the SIP registration expires mid-shift due to network jitter, you’ll get 408s. Coordinate with your telephony team to set keep-alive intervals to 30 seconds for secondary trunks.
Using Manual Override for Shifts: For agents working on high-risk outbound campaigns, consider using manual schedule overrides instead of auto-generated shifts. This allows you to ensure that only agents with confirmed, stable trunk connections are included in the predictive pool during peak hours.
Monitoring Schedule Adherence: Use the WFM analytics dashboard to track adherence vs. actual call attempts. If you see a spike in 408s correlating with specific shift changes, it’s likely a sync issue between WFM status and telephony registration.
This approach minimizes the risk of dropped calls by aligning workforce schedules with telephony stability rather than relying solely on campaign settings.