The blockage function is used to regulate SIP messages arriving at WebLogic SIP Server. WebLogic SIP Server 2.0.1 provides the following three functions to block these messages.
Incoming Blockage - The function to destroy the incoming SIP messages when the number of unprocessed SIP messages reaches the maximum capacity of the execute queue.
Incoming-Call Regulation - The function to regulate the received initial SIP messages.
Application Session Regulation - The function to regulate the number of application sessions processed by the application.
The incoming blockage function is used to destroy the incoming SIP messages when the number of unprocessed SIP messages reaches the maximum capacity of the WebLogic Server execute queue used to process these SIP messages. Once this function becomes enabled, WebLogic SIP Server continues to destroy the incoming SIP messages for a period of time. When WebLogic SIP Server destroys a request or response, it acts as follows:
| Request | Returns the message “503 Server Busy” as a response and destroys the request. |
| Response | Destroys the response. |
The execute queue to be performed the incoming blockage function is specified in the "thread-pool-name" of the "transport" tag in the sipserver.xml. The maximum length of the execute queue can be configured through the Administration Console.
The incoming-call regulation targets only the initial SIP requests arriving at WebLogic SIP Server. Since only the initial requests are destroyed, the SIP dialog once established will not be the target of the incoming-call regulation. The regulated SIP request, as in the blockage of incoming message, is not transmitted to the application and is destroyed with the return of “503 Service Busy” response.
This function is performed by monitoring one of the following two values. These settings are contained in the WebLogic SIP Server configuration file (sipserver.xml) and selected by the system administrator. (They can not be configured simultaneously.)
The session generation rate (sessions/sec) is calculated by the number of application sessions created during the last 5 seconds. When the session generation rate exceeds the specified regulation trigger rate, WebLogic SIP Server regulates the initial requests until the session generation rate becomes smaller than the specified regulation termination rate. The incoming-call regulation based on the session generation rate is specified in the income-call tag in the sipserver.xml. The income-call tag has the following tags:
| Tag Name | Description |
|---|---|
| threshold-policy | Specify "session-rate" here. |
| threshold-value | Specify the application session generation rate that triggers the regulation (sessions/sec) here. |
| release-value | Specify the application session generation rate that terminates the regulation (sessions/sec) here. |
Here is an example setting in the sipserver.xml. It is configured to trigger the regulation at 50 sessions/sec and terminate the regulation at 40 sessions/sec.
<income-call>
<threshold-policy>session-rate</threshold-policy>
<threshold-value>50</threshold-value>
<release-value>40</release-value>
</income-call>
The incoming-call regulation based on the execute queue length is performed by monitoring the WebLogic Server execute queue. The execute queue to be monitored is specified in the "thread-pool-name" of the "transport" tag in the sipserver.xml. When the execute queue length exceeds the specified regulation trigger length, WebLogic SIP Server regulates the initial requests until the execute queue length becomes smaller than the specified regulation termination rate. The incoming-call regulation based on the execute queue length is specified in the income-call tag in the sipserver.xml. The income-call tag has the following tags:
| Tag Name | Description |
|---|---|
| threshold-policy | Specify "queue-length" here. |
| threshold-value | Specify the queue length that triggers the regulation here. |
| release-value | Specify the queue length that terminates the regulation here. |
Here is an example setting in the sipserver.xml. It is configured to trigger the regulation at the queue length 32.0.10 and terminates the regulation at the queue length 30000.
<income-call>
<threshold-policy>queue-length</threshold-policy>
<threshold-value>32.0.10</threshold-value>
<release-value>30000</release-value>
</income-call>
The application session regulation function is used to regulate creation of application sessions for each application. When the number of application sessions that can exist concurrently in each application exceeds the specified maximum value, WebLogic SIP Server rejects creation of an application session with the “503 Application Busy” response.
To enable this function, place the extension configuration file "WEB-INF/sse.xml" for each application. If the file does not exist, this function does not work.
The application session regulation function is specified in the session-config tag. The session-config tag has the following tag:
| Tag Name | Description |
|---|---|
| max-app-session-count | Specify the maximum number of application sessions that can exist concurrently here. |
In this example, the maximum number of application sessions that can exist concurrently is configured to 100.
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE sse-app SYSTEM "file:/sse_1_0.dtd">
<sse-app>
<session-config>
<max-app-session-count>100</max-app-session-count>
</session-config>
</sse-app>