40 DNS and caching satisfy this test because both services facilitate use of the network without altering the fundamental character of the telecommunications service. DNS does so by “allow[ing] more efficient use of the telecommunications network by facilitating accurate and efficient routing from the end user to the receiving party.” Id. at 5768 ¶ 368. Caching qualifies because it “enabl[es] the user to obtain more rapid retrieval of information through the network.” Id. at 5770 ¶ 372 (internal quotation marks omitted). US Telecom does not challenge the applicability of the adjunct-to-basic standard, nor does it give us any reason to believe that the Commission’s application of that standard was unreasonable. See GTE Service Corp. v. FCC, 224 F.3d 768, 772 (D.C. Cir. 2000) (“[W]e will defer to the [Commission’s] interpretation of [the Communications Act] if it is reasonable in light of the text, the structure, and the purpose of [the Communications Act].”). As to US Telecom’s second point, the Commission justified treating third-party DNS and caching services differently on the ground that when such services are “provided on a stand-alone basis by entities other than the provider of Internet access service[,] . . . there would be no telecommunications service to which [the services are] adjunct.” 2015 Open Internet Order, 30 FCC Rcd. at 5769 ¶ 370 n.1046. Again, US Telecom has given us no basis for questioning the reasonableness of this conclusion. Once a carrier uses a service that would ordinarily be an information service—such as DNS or caching—to manage a telecommunications service, that service no longer qualifies as an information service under the Communications Act. The same service, though, when unconnected to a telecommunications service, remains an information service.