The SBC Core supports dialog stateful variables to allow storing values during SMM processing of messages, and then later using the same values for SMM processing of the other messages in the same dialog. The SBC supports dialog stateful variables for INVITE, REGISTER, and Out-of-Dialog SUBSCRIBE messages. The SBC also supports dialog stateful variables for Out-of-Dialog MESSAGE messages but only on the egress leg. That is, the dialog stateful variables for MESSAGE messages are created and accessed on the outgoing leg only. The values of stateful variables are preserved for the active dialogs. These values are accessible during the SMM rule processing on the subsequent messages.

IMPORTANT

Do not use SMM to manipulate To, From, Contact and Request URIs in incoming REGISTER messages.

Note
  • The dialog stateful variables do not support NOTIFY messages which are received prior to receiving the 200 OK response to the egress SUBSCRIBE.
  • For REGISTER messages, dialog stateful variables are accessible by refresh REGISTER requests but not by INVITE/SUBSCRIBE sent for a registered user. The refresh-REGISTERs are expected to have same call-id as that of initial REGISTER.
Note

The maximum supported size of data stored in a dialog stateful variable is 6 kB (6,144 bytes). The SBC ignores the data if the data size exceeds the size limit; no data is written in the variable.

Note

When dialog transparency is enabled and "Advanced SMM" functionality is required:

  • If both inputAdapterProfile and outputAdapterProfile are provisioned, enable the advancedSMM flag on both SIP Adapter Profiles (inputAdapterProfile and outputAdapterProfile).
  • If only one SIP Adaptor Profile is provisioned (either inputAdapterProfile or outputAdapterProfile), enable the advancedSMM flag only for the provisioned SIP Adaptor Profile. 

Advanced SMM example: