SIP Request Method Throttling

You can configure throttling mechanisms for SIP INVITEs and REGISTERs using session agent constraints. However, you might want to throttle other types of SIP methods, and for those methods you should use the rate constraints configuration available both in the session constraints (which you then apply to a SIP interface or a realm) and the session agent configurations.

Oracle recommends you use session agent constraints for session-rate INVITE throttling and registration-rate for REGISTER throttling.

For SIP access deployments, you can configure rate constraints for individual method types along with a set of burst and sustain rates. These constraints can help to avoid overloading the core network. In addition, they restrain the load non-INVITE messages use, thus reserving capacity for INVITE-based sessions and Registrations

When you configure SIP request method throttling, you must exercise care because it is possible to reject in-dialog requests. Therefore, Oracle recommends you do NOT configure constraints—although the configuration allows you to and will not produce error messages or warnings if you set them—for the following SIP method types:

• ACK
• PRACK
• BYE
• INFO
• REFER

However, the Oracle® Enterprise Session Border Controller is likely to throttle NOTIFY requests despite their being part of a Subscribe dialog.

Therefore, the methods you will most likely configure for throttling are:

• NOTIFY
• OPTIONS
• MESSAGE
• PUBLISH
• REGISTER

The Oracle® Enterprise Session Border Controller counts Re-INVITEs and challenged responses against the throttle limit, but does not check to determine if the constraints have been exceeded for either.

You can configure separate constraints—inbound and outbound values for burst and sustain rates—for each different method type you configure. Although you should use session agent constraints (and not rate constraints) for INVITEs, if you also set up rate constraints for INVITEs, then the smallest configured value takes precedence.