290. This article provides the international equivalent of the power established for domestic use in Article 17. Frequently, at the request of a Party in which a crime was committed, a requested Party will preserve traffic data regarding a transmission that has travelled through its computers, in order to trace the transmission to its source and identify the perpetrator of the crime, or locate critical evidence. In doing so, the requested Party may discover that the traffic data found in its territory reveals that the transmission had been routed from a service provider in a third State, or from a provider in the requesting State itself. In such cases, the requested Party must expeditiously provide to the requesting Party a sufficient amount of the traffic data to enable identification of the service provider in, and path of the communication from, the other State. If the transmission came from a third State, this information will enable the requesting Party to make a request for preservation and expedited mutual assistance to that other State in order to trace the transmission to its ultimate source. If the transmission had looped back to the requesting Party, it will be able to obtain preservation and disclosure of further traffic data through domestic processes.
291. Under Paragraph 2, the requested Party may only refuse to disclose the traffic data, where disclosure is likely to prejudice its sovereignty, security, ordre public or other essential interests, or where it considers the offence to be a political offence or an offence connected with a political offence. As in Article 29 (Expedited preservation of stored computer data), because this type of information is so crucial to identification of those who have committed crimes within the scope of this Convention or locating of critical evidence, grounds for refusal are to be strictly limited, and it was agreed that the assertion of any other basis for refusing assistance is precluded.