The HSS (Home Subscriber Server) is the concatenation of the HLR (Home Location Register) and the AuC (Authentication Center) â two functions being already present in pre-IMS 2G/GSM and 3G/UMTS networks.
Three Days Grace's music has been described as post-grunge, hard rock, alternative rock, alternative metal and nu metal. Their self-titled album mostly uses the sounds of alternative metal and post-grunge. However, on their second album One-X, the band had more guitar solos and a more melodic sound.
There are three major types of rock: igneous, sedimentary, and metamorphic. The rock cycle is an important concept in geology which illustrates the relationships between these three types of rock, and magma. When a rock crystallizes from melt (magma and/or lava), it is an igneous rock.