SMM Rules

Each SIP Adaptor Profile contains up to 64 rules that are applied sequentially to messages. Each rule can have up to 20 criteria and up to 20 actions. The SIP Message Manipulation (SMM) rule inspects each SIP message and looks for a match with its defined criteria. If all the criteria are met, the SMM rule applies its defined action(s) to the message and sends the message for further processing.

Rules within a profile are applied to messages sequentially in order of the rule index numbers.

• If a message meets a rule criteria, it is processed by that rule and then passed on to the next rule. Therefore, a message might be modified by more than one rule.
• If a message does not meet a rule criteria, it is passed on to the next rule.
• If a message does not meet any criteria in any of the rules, it is passed on unmodified.

Each rule consists of two main parts:

• One or more Criteria
• One or more Actions

Criteria includes the conditions to execute the rules. The action part specifies the actual modifications to perform.

SMM Rule Categories

Rules are logically grouped into the following categories.

• Message Rule—Ignore an inbound message by dropping silently or by not sending an outbound message. Reject a message (requests) with the configured response code. Create a URI.
• Header Rule—Add/delete headers or modify their content.
• Parameter Rule—Add/delete parameters in a header or modify their content.
• Token Rule—Add/delete tokens in a header or modify their content.
• Internal Variable Rule—Set or compare the values of internal variables. Criteria should specify that modification must be performed on the variable and the variable ID.
• Global Variable Rule—Use Global Variables to modify a header/parameter/token/message body/variable etc. Criteria should specify the Global Variable name and the name of the header/parameter/token/variable etc. which needs to be modified with global variable.
• Message Body Rule—Add/delete or modify the message body contents. Criteria should specify that modification must be performed on the Message Body.

Unknown Headers and Parameters

As rules are defined, some headers or parameters may be unknown to the SBC (e.g., a rule to remove a proprietary header). In such cases, even though the SBC does not have any information about the type of header or parameter, it can still refer to the tokens in these constructs.
It is assumed that if a rule refers to a userpart or hostpart, the corresponding header or parameter is in URL format.

• Userpart value is the content before "@". If there is a ";" in that portion, the userpart value contains only the parts present before it.
• Hostpart value is the content after "@". The value contains the content until the end of the header line or until a ";" or ">" is met.

Adding SMM Rules on a Live System