Configuring Overload Protection for Session Agents

The Oracle® Enterprise Session Border Controller offers two methods to control SIP registrations to smooth the registration flow.

You can limit the:

• number of new register requests sent to a session agent (using the max-register-sustain-rate parameter)
• burstiness which can be associated with SIP registrations

The first method guards against the Oracle® Enterprise Session Border Controller’s becoming overwhelmed with register requests, while the second method guards against a transient registration that can require more than available registration resources.

SIP registration burst rate control allows you to configure two new parameters per SIP session agent—one that controls the registration burst rate to limit the number of new registration requests, and a second to set the time window for that burst rate. When the registration rate exceeds the burst rate you set, the Oracle® Enterprise Session Border Controller responds to new registration requests with 503 Service Unavailable messages.

Note that this constraint is not applied to re-registers resulting from a 401 Unauthorized challenge request.

To configure overload protection for session agents:

1. In Superuser mode, type configure terminal and press Enter.

   ORACLE# configure terminal

2. Type session-router and press Enter to access the system-level configuration elements.

   ORACLE(configure)# session-router

3. Type session-agent and press Enter. The system prompt changes to let you know that you can begin configuring individual parameters.

   ORACLE(session-router)# session-agent
   ORACLE(session-agent)#

4. constraints—Enable this parameter to set the sustained rate window constraint you configure in the next step. The default value is disabled. The valid values are:

   • enabled | disabled

5. sustain-rate-window—Enter a number to set the sustained window period (in milliseconds) that is used to measure the sustained rate. The default value is zero (0). The valid range is:

   • Minimum—10

   • Maximum—4294967295

     The value you set here must be higher than or equal to the value you set for the burst rate window.

     Note:

     If you are going to use this parameter, you must set it to a minimum value of 10.
6. max-register-sustain-rate—Enter a number to set the maximum number of registrations per second you want sent to the session agent. The default value is zero (0), disabling the parameter. The valid range is:

   • Minimum—0

   • Maximum—4294967295

7. register-burst-window—Define the window size in seconds for the maximum number of allowable SIP registrations. 0 is the minimum and default value for this parameter; the maximum value is 999999999.
8. max-register-burst-rate—Enter the maximum number of new registrations you want this session agent to accept within the registration burst rate window. If this threshold is exceeded, the Oracle® Enterprise Session Border Controller will respond to new registration requests with 503 Service Unavailable messages. 0 is the minimum and default value for this parameter; the maximum value is 999999999.
9. Save and activate your configuration.