ALBANY, N.Y. — New York’s attorney general suspects there’s little difference between broadband’s fast lanes and the slower freight of ordinary Internet access.

In letters to the state’s three major Internet providers, the attorney general has asked them to validate claims their customers are getting the access speeds promised, especially for premium services.

The agency said it’s concerned that Time Warner, Verizon and Cablevision subscribers might not be getting the speeds advertised. In letters Friday, senior enforcement counsel Tim Wu wrote that the office has authority to subpoena documents and take legal action to stop deceptive business practices, requesting detailed information by Nov. 8.

Wu wrote that the office had two concerns.

The first is that the speeds in the so-called last mile – the wiring closest to subscribers – “may deviate far enough from the speeds advertised to render the advertising deceptive,” he wrote.

The second is the quality of connections between the three providers and sites such as Yahoo or Netflix. There have been many consumer complaints, officials said.

Cablevision Systems Corp. told The Associated Press on Monday that it will be happy to provide information to the attorney general.

“Optimum Online consistently surpasses advertised broadband speeds, including in FCC and internal tests,” spokeswoman Sarah Chaikin said.

Time Warner Cable Inc. and Verizon Communications Inc. didn’t immediately respond Monday to requests for comment.

The attorney general’s office is seeking each provider’s total broadband customers since 2011, grouped by service levels. It also wants all disclosures to actual or potential customers about Internet speeds since 2013, substantiation for specific speed claims, related customer complaints and copies of Internet interconnection agreements.

After the attorney general’s review of responses and documents, company officials will be invited in to discuss their broadband marketing practices and services, Wu wrote.