Service type of users in the domain, including hsi(1), stb(2), and voip(3). The default value is hsi. The High Speed Internet (hsi) service is applicable to users that access the network through PPP, 802.1X, or IPoE. If this service is used, the multicast feature of the access module is disabled to save system resources. The Set Top Box (stb) service is applicable to users that access the network through stb. If this service is used, the multicast feature of the access module is enabled to improve the performance of the multicast module. The Voice over IP (voip) service is applicable to users that access the network through IP phones. If this service is used, the Quality of Service (QoS) module increases the priority of voice traffic to reduce the transmission delay for IP phone users. Default value is hsi.