Comment #11 on issue 2354 by jean.deruelle: B2buaHelper.createResponseToOriginalRequest() does not set different To tag to created response.
http://code.google.com/p/mobicents/issues/detail?id=2354
Strictly speaking we shouldn't even forward the provisonnal responses with different to tag neither but we allow it so that the UAC can play mandatory early media as explained here http://java.net/projects/jsip/lists/users/archive/2011-04/message/10
See section below "8.2.6.2 Headers and Tags If a request contained a To tag in the request, the To header field in the response MUST equal that of the request. However, if the To header field in the request did not contain a tag, the URI in the To header field in the response MUST equal the URI in the To header field; additionally, the UAS MUST add a tag to the To header field in the response (with the exception of the 100 (Trying) response, in which a tag MAY be present). This serves to identify the UAS that is responding, possibly resulting in a component of a dialog ID. The same tag MUST be used for all responses to that request, both final and provisional (again excepting the 100 (Trying)). Procedures for the generation of tags are defined in Section 19.3."
