Comcast Corp. is opening up three new retail locations in Greater Baltimore as the region’s dominant internet provider rolls out new services for customers. The Philadelphia-based telecom giant will open Xfinity Stores in Catonsville, Glen Burnie and Westminster by the end of the week. The offering allows customers to get their internet hooked up the same day they sign up for Xfinity, Comcast’s primarily residential brand for internet, cellular and cable plans. Comcast expects to offer the new service throughout its entire network by early next year. READ MORE:3 Xfinity Stores opening as new service rolls outCHECK OUT WBAL:Get all the latest Baltimore news, weather and sports.