Mapping the History-Info Cause Parameter

You can configure ESBC to map the History-Info's cause 380 parameter to the Diversion header's reason=unknown parameter. You can configure the applicable parameter, hist-to-div-for-cause-380, in both the sip-config and sip-interface, with the egress sip-interface setting taking precedence. This parameter only applies when you set the applicable sip-interface interworking mode to hist2div. The verify-config command informs you if there is a hist-to-div-for-cause-380 without a corresponding hist2div.

By default, the hist-to-div-for-cause-380 parameter is disabled, which causes the ESBC to transparently forward the Hisory-Info entry with cause 380. Enabling the parameter makes the ESBC interwork the parameter, allowing it to be understood by devices that support Diversion headers.

When using hist-to-div-for-cause-380 for 380 cause mapping, the ESBC places those headers at the top of the Diversion header list. This is true regardless of how many History-Info entries are present.