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 Communications 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 Communications 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.
About Counters and Statistics
Each rate constraint you configure for a SIP method tracks its own counters. For example, if you configure a rate constraint for the PUBLISH method, the burst and sustain rates you set for it apply only to the PUBLISH method and not to any other methods for which you might set up rate constraints. You can, however, set the burst rate window in the session constraints configuration that will apply to all methods configured as rate constraints.
The Oracle Communications Session Border Controller captures statistics for SIP methods throttled by rate constraints for SIP interfaces and session agents; it does not capture these statistics for the global SIP configuration.
SIP Request Method Throttling Configuration
This section shows you how to set up rate constraints for session constraints (which are then applied to SIP interfaces) and session agents.
To use this feature, you must enable the extra-method-stats parameter in the global SIP configuration.
To set the extra-method-stats parameter in the global SIP configuration:
Rate Constraints for SIP Interfaces
To apply rate constraints to SIP interfaces, you need to configure rate constraints in the session constraints configuration and then apply the session constraints to the SIP interface where you want them used.
Note that you need to set up the parent session-constraint configuration to save any rate constraints you configure.
To configure rate constraints: