Charter institutions connected to the CalREN backbone include:   Other non-charter participants include:  CalREN is a three-tiered network consisting of a statewide optical backbone to which schools and other institutions in California connect at Gigabit speeds via leased circuits obtained from telecom carriers or fiber-optic cable. These tiers include:   All three network tiers operate independently. This enables network and other researchers on the XD and HPR tiers to push the boundaries of network research and performance without impacting performance for the other tiers. CENIC also engages in networking peering relationships, in particular Pacific Wave (a joint project between CENIC and the Pacific Northwest Gigapop, the University of Southern California, and the University of Washington), which provides peering facilities along the Pacific coast of the United States. Pacific Wave participants include networks in Australia, Canada, Japan, Korea, Qatar, Taiwan, Singapore, and the United States. CENIC engaged in peering via the TransitRail national-level peering structure. TransitRail has been merged with Internet2's Commodity Peering Service. CalREN also connects to the California Telehealth Network, ESnet (Energy Sciences Network), Internet2, CUDI (the Corporación Universitaria para el Desarrollo de Internet), the Mexican high-bandwidth research and education network, redCLARA (the Cooperación Latino-Americana de Redes Avanzadas), and CAnet4 (the Canadian optical research and education network, managed by CANARIE). CENIC is also a member of the Global Lambda Integrated Facility, which promotes optical networking to support grid computing. CalREN was expanded by funding through the state of California and its Digital California Project to include K-12 public education. When funding sources changed, the K-12 portion became the K-12 High Speed Network (K12HSN), which is managed by the Imperial County Office of Education.