Exhibit 3.173

State of Delaware

Secretary of State

Division of Corporations

Delivered 04:36 PM 08/28/2003

FILED 04:28 PM 08/28/2003

SRV 030561038 – 3697806 FILE

CERTIFICATE OF FORMATION

OF

CHARTER FIBERLINK – ALABAMA, LLC

1. The name of the limited liability company is Charter Fiberlink – Alabama, LLC.

2. The address of its registered office in the State of Delaware is 2711 Centerville Rood, Suite 400, Wilmington, Delaware, 19808, County of New Castle. The name of its registered agent at such address is Corporation Service Company.

IN WITNESS WHEREOF, the undersigned has executed this Certificate of Formation of Charter Fiberlink – Alabama, LLC this 28th day of August, 2003.

/s/ Janeen G. Domagalski

Janeen G. Domagalski

Authorized Person