1. A method performed by a network node of a communication network for making a Hypertext Transfer Protocol (HTTP) media stream accessible to a client, the method comprising: generating, by a network node, a Media Presentation Description that comprises at least two period elements sequentially arranged according to a media play timeline of a media content, at least a first period element of the period elements being provided with at least one representation and at least a second period element 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 Uniform Resource Identifier (URI), wherein each of the at least one media segment URI references at least one media segment of said HTTP media stream; wherein each of the at least one representation and the at least two alternative representations includes at least one setting for processing the first period element and the second period element, respectively, and wherein one of the at least two alternative representations includes at least one setting that differs from the other alternative representation and the at least one representation of the first period element, such that the second period element is configured to provide a segment of the media stream with the at least one setting not supported by the first period element; providing, by the network node, the Media Presentation Description to the client; wherein the Media Presentation Description is configured to be updated by the network node.