Exhibit 23.3 [Arthur Anderson Letterhead] CONSENT OF INDEPENDENT PUBLIC ACCOUNTANTS As independent public accountants, we hereby consent to the inclusion in this Form S-4 Registration Statement of our Splitrock Services, Inc. report dated October 16, 2000 and to all references to our Firm included in or made a part of this Registration Statement. /s/ Arthur Anderson LLP Chicago, Illinois October 16, 2000