5 Jonathan B. Sallet, General Counsel, Federal Communications Commission, and Jacob M. Lewis, Associate General Counsel, argued the causes for respondents. With them on the brief were William J. Baer, Assistant Attorney General, U.S. Department of Justice, David I. Gelfand, Deputy Assistant Attorney General, Kristen C. Limarzi, Robert J. Wiggers, Nickolai G. Levin, Attorneys, David M. Gossett, Deputy General Counsel, Federal Communications Commission, James M. Carr, Matthew J. Dunne, and Scott M. Noveck, Counsel. Richard K. Welch, Counsel, Federal Communications Commission, entered an appearance. Kevin Russell and Pantelis Michalopoulos argued the cause for intervenors, Cogent Communications, Inc., et al. in support of respondents. With them on the joint brief were Markham C. Erickson, Stephanie A. Roy, Andrew W. Guhr, Robert M. Cooper, Scott E. Gant, Hershel A. Wancjer, Christopher J. Wright, Scott Blake Harris, Russell M. Blau, Joshua M. Bobeck, Sarah J. Morris, Kevin S. Bankston, Seth D. Greenstein, Robert S. Schwartz, Marvin Ammori, Michael A. Cheah, Deepak Gupta, Erik Stallman, Matthew F. Wood, James Bradford Ramsay, Jennifer Murphy, Harold Jay Feld, David Bergmann, and Colleen L. Boothby. Hamish Hume and Patrick J. Whittle entered appearances. Michael K. Kellogg, Scott H. Angstreich, Miguel A. Estrada, Theodore B. Olson, Jonathan C. Bond, Stephen E. Coran, S. Jenell Trigg, Jeffrey A. Lamken, Matthew A. Brill, Matthew T. Murchison, Jonathan Y. Ellis, Helgi C. Walker, and Michael R. Huston were on the joint brief for intervenors AT&T Inc., et al. in support of respondents in case no. 151151.