Configuration of maximum number of simultaneous devices that can register concurrently
For MDA, an administrator can specify a minimum of 2 and maximum of 10 SIP devices that can concurrently register with Session Manager. However, Avaya recommends that out of the 10 SIP endpoints only one endpoint should be a Device Adapter UNIStim endpoint. This is because registering two or more UNIStim endpoints with the same TN is non-deterministic in MDA.
If a user wants to use two or more Device Adapter UNIStim endpoints, then Avaya recommends that you set Max. Simultaneous Devices to 1. This is called Sequential Registration and not MDA.
Configuration for how Session Manager should handle new endpoint registration request if maximum registered devices is reached
Whether Session Manager registers a new endpoint when the maximum number of concurrent registered devices is reached depends on whether an administrator selects or clears the Block New Registration When Maximum Registrations Active check box:
If the configuration is to block the endpoint from registering, the endpoint SIP registration request is rejected.
If a user wants to register a new device, the user must manually un-register an existing registered device.
If the configuration is to allow the endpoint to register, the endpoint SIP registration request is allowed. However, Session Manager un-registers an existing device that is registered for the longest period of time before registering the new device.
Scenarios when the maximum number of registered devices is reached
The following are the scenarios if the maximum number of registered devices is reached:
If the Block New Registration When Maximum Registrations Active check box is clear and the maximum number of registered devices is reached, a new registration attempt clears the oldest prior registration.
Because Max. Simultaneous Devices is set to 2 or more, Session Manager selects and un-registers the device that has been registered for the longest period of time from the currently registered devices.
If the Block New Registration When Maximum Registrations Active check box is selected, and if the maximum number of registered devices is reached, then:
Either of the following is applicable if a new registration request is received:
Session Manager rejects the new registration request.
A user must manually log out of a currently registered device to register a new device.
In an event of a network failure, when the endpoint loses connectivity and tries to re-register, then:
Till Device Adapter Release 8.1.1, Session Manager processed this as a new registration request. After the keep-live signaling detected a connection failure, Session Manager un-registered the existing registered device and allowed the new SIP registration. However, this caused a delay in fail over.
In Device Adapter Release 8.1.2, enhancements in high availability and fail over remove this limitation. Session Manager identifies the endpoint by using the device ID and processes the fail over attempt as a re-registration request rather than a new registration request by the endpoint and registers the endpoint.
