Service Failover and Load Balancing
DIDWW provides mechanisms for failover and load balancing between its system and customer equipment. These mechanisms include DNS SRV for SIP-based failover and Trunk Groups for managing multiple SIP trunks efficiently.
DNS SRV
The DNS SRV mechanism is fully supported by the DIDWW system. Using DNS SRV, calls can be directed to a customer-defined DNS SRV record, which specifies multiple destinations and their respective priorities for failover.
How It Works
For UDP SIP transport, the system resolves the following record:
_sip._udp.<customer.domain>
For TCP SIP transport, the system resolves the following record:
_sip._tcp.<customer.domain>
In both cases, <customer.domain> corresponds to the trunk host value.
Enabling DNS SRV for SIP Trunks
To enable DNS SRV for SIP trunks, leave the port field empty.
Note
The DNS SRV mechanism operates at the SIP transaction layer. If a failover occurs, a new Call Detail Record (CDR) is generated for each attempt.
Trunk Groups
Trunk Groups allow customers to bundle multiple SIP trunks, distributing traffic for DID numbers across multiple gateways. This feature provides flexible configuration options for failover and load balancing.
Configuration Options
You can configure the following parameters to manage Trunk Groups effectively:
Priority and Weight: Specify the order and distribution of calls among trunks.
Ringing Timeout: Set the maximum time to wait for a response from a trunk.
Re-routing Disconnect Rules: Define conditions for redirecting calls.
Capacity: Limit the number of simultaneous calls per trunk.
Call Detail Records (CDRs)
For each call termination attempt within a Trunk Group, DIDWW generates a separate Call Detail Record (CDR). Each CDR represents an individual attempt to route the call to the destination network.
The key attributes related to call attempts while using call events CDR Streaming include:
Attribute |
Type |
Description |
Example |
|---|---|---|---|
routing_attempt |
Integer |
Specifies the sequential attempt number for routing the call. The first attempt is recorded as |
|
is_last_cdr |
Boolean |
Indicates whether this CDR corresponds to the final attempt in the routing process. If set to |
|
By utilizing DNS SRV records and Trunk Groups, DIDWW enables advanced failover and load-balancing strategies for inbound DID numbers. In scenarios where a call cannot be routed successfully on the first attempt, the system can attempt alternative destinations based on predefined routing logic.
Additional information:
For User Interface Call Logs, visit the documentation page.
For more details about CDR Streaming CDR attributes, visit the documentation page.