Overview
To support scalable call handling in OXE networks, two valid approaches are available: WebRTC Gateway Scalability and the new Dynamic Overflow. Both build on the existing capability to share a pool of WebRTC gateways across an OXE network, offering flexible options for managing overflow traffic.
Scalability Options
Depending on the customer’s topology and deployment size, especially in multi-site or multi-gateway environments, either of the following methods can be used:
- ARS overflow on trunk saturation: A native OXE mechanism that triggers overflow when the trunk reaches capacity.
- Max call handling on the WebRTC gateway (Dynamic Overflow): Calls are initiated by OXE, but rejected by the gateway if its limit is reached. OXE then routes the call to the next SIP gateway.
Gateway-side rejection is suitable for occasional peak loads. If overflow is expected regularly, managing limits directly in OXE is generally more efficient.
What’s New with Dynamic Overflow
The Dynamic Overflow feature introduces two key enhancements:
- Centralized Capacity Management: WebRTC gateway call capacity is now managed at the Rainbow level, simplifying configuration and ensuring consistency across the network.
- Automatic Overflow Trigger: When a gateway reaches its configured call capacity, it sends a SIP 406 “Not Acceptable” response to OXE. OXE then automatically overflows the call to the next available gateway—no static limit configuration required on the OXE side.
Configuration Steps
1. Set Maximum Concurrent Calls in Rainbow
This step is optional and only relevant for complex OXE configurations requiring overflow behavior.
Note: Only BP Admins with Operations role can configure the WebRTC gateway call limit in Rainbow.
- Navigate to the WebRTC Gateway Details page in Rainbow Web Admin.
- Locate the new section: Maximum Concurrent Calls.
- Enable the checkbox to activate the limit.
- Enter the desired maximum number of concurrent calls.
Warning: After setting the value, you must restart the WebRTC gateway for the change to take effect.
Notes:
● If the checkbox remains unchecked, the WebRTC gateway behaves as before - serving calls without a defined upper limit.
● Once the limit is reached, the WebRTC gateway will respond with SIP 406, triggering OXE’s native overflow mechanism.
2. OXE Configuration
No changes are required on the OXE software side. The dynamic overflow leverages OXE’s existing SIP gateway list and overflow logic.
- Ensure multiple WRGs are declared in OXE’s SIP gateway list.
- Upon receiving a SIP 406 from a WebRTC gateway, OXE will automatically route the call to the next available WebRTC gateway.