Service Failover and Load balancing

There are few mechanisms of failover and load-balancing on call leg between DIDWW system and customer equipment - DNS SRV mechanism and Trunk Group


DNS SRV mechanism is fully supported by DIDWW system. Calls can be sent to customer DNS SRV record which contains multiple destinations and priorities for failover.

For UDP SIP transport system will resolve record:


For TCP transport:


Where <customer.domain> is trunk host value.

To enable DNS SRV mechanism for SIP trunks just leave port empty.

DNS SRV mechanism working on SIP transaction layer so new additional CDR will be saved in case of failover.

Trunk group

Customer can bundle trunks to trunk group to distribute traffic to DID number over multiple gateways. Priority, Weight, Ringing Timeout, Re-routing Disconnect Rules and capacity configuration of trunks allows to configure flexible rules of failover and load-balancing.

DIDWW will save separate CDR for each call termination attempt to trunk included in trunk group, CDR field routing_attempt will be incremented for each attempt. is_last_cdr flag will be set true for last attempt.