A content server may receive from a user device a request for a content asset and may send to the playback device a permit for accessing the content asset. The permit may be used by the content server in order to enforce a concurrency restriction, or a number of concurrent playbacks of one or more content assets desired or permitted by the playback device. In response to receiving a request for a content asset segment associated with a content asset, the content server may determine whether the number of permits currently granted to the playback device exceeds the number of desired or permitted accesses by the playback device, or a group of playback devices, to the content asset or one or more content assets. If so, then the content server may discontinue sending to the playback device any further content asset segments associated with that content asset.