The construction method of NALU (Network Abstraction Layer Unit) for IPv6 label switching and its using algorithms of video encoding, QoS control, and decoding are provided. According to an embodiment of the present invention, the NALU format is composed of the NALH (Network Abstraction Layer Header) including the label and the NAL (Network Ab straction Layer) payload. Here, the label is determined based on layer information which is combination of a spatial scalable level, a temporal scalable level, and a quality scalable level of the encoded data. The decoder uses the label to decide which one of multiple decoding modules is used to decode the current NAL payload. Moreover, the label can be included in the packet header so that the MANE (Media Aware Network Element) can use the label to decide whether to forward the packet or drop it. For example, the label in the packet header can be used for QoS control of video service by using the flow label field in IPv6 packet header. The IPv6 router can identify priority of the video packet by using the 20 bit long flow label, into which the label in NALH can he inserted. According to the embodiment, the MANE assumed in the MPEG and JVT (Joint Video Team) can he implemented effectively.