1. A method performed by a server of a communication network for making a HTTP media stream accessible to a client, the method comprising: generating a Media Presentation Description that comprises at least two period elements sequentially arranged according to a media play timeline, each period element being provided with at least one representation and at least one of the period elements is provided with at least two alternative representations, wherein each of the representations is provided with an ordered sequence of at least one media segment URI, wherein each of the at least one media segment URI references at least one media segment of said HTTP media stream; and providing the Media Presentation Description to the client.