Maintaining that T-Mobile US has struggled to reach data roaming agreements with rivals on reasonable terms, T-Mobile  asked the  agency on Tuesday to provide “prospective guidance and predictable enforcement criteria for determining  whether the terms of any data roaming agreement or proposal meet the ‘commercially reasonable’ standard adopted by  the Commission.”  In a petition for expedited declaratory ruling, T-Mobile lamented that,  even with the enactment of  wireless data roaming rules by the FCC in 2011, “real world industry experience shows that providers continue to be  stymied in their efforts to negotiate data roaming agreements on commercially reasonable terms.”  According to T-Mobile,  these problems are attributable “to certain ambiguities in the ‘commercially reasonable’ standard” that “could not have  been foreseen” by the FCC when the data roaming rules were approved.  While an accompanying declaration signed by TMobile senior vice president Dirk Mosa contends that “certain ‘must-have’ carriers are using the ambiguity of the Data  Roaming Order as a shield to protect and extend unreasonable roaming practices,” the petition spotlights T-Mobile’s  experience with AT&T as one that “provides a concrete example of the need for further action by the Commission.”  To  resolve such ambiguity, T-Mobile urged the FCC to consider four proposed benchmarks for assessing commercial  reasonableness within the data roaming context.  These benchmarks include: (1) whether wholesale roaming rates offered  to retail competitors exceed relevant retail rates, (2) whether a wholesale roaming rate offered to a competitor  “substantially exceeds the roaming rates charged to foreign carriers” whose  customers roam in the U.S., (3) whether a  wholesale roaming rate exceeds the wholesale rate charged to mobile virtual network operators, and (4) how the proposed  wholesale roaming rate compares to other competitively negotiated wholesale rates.  Although officials of AT&T offered no  comment, a spokesman for the Rural Wireless Association (RWA) observed:  “the fact that T-Mobile . . . is having difficulty  negotiating commercially reasonable data roaming rates with ‘must have’ roaming partners in order to offer truly  nationwide coverage underscores the difficulties experienced by the great majority of RWA’s carrier members, who are  much smaller and have even less power at the negotiating table.”