SIP Thor is a Peer-to-Peer overlay that allows for load balancing, self-organization and geographical distribution of SIP infrastructure elements. SIP Thor allows for distribution of hardware resources in multiple datacenters and in different geographical locations. Using SIP Thor all relevant computing resources can be virtualized allowing for running the SIP services "in the cloud" with a high scalability/cost ratio. The infrastructure can scale deterministically to handle millions of end-points.
dramatically reducing the operational costs. SIP Thor implements an overlay network for SIP Proxy/Registrar and other network centric functions like DNS, presence agent, database storage, voicemail, xcap policy and provisioning.
The P2P layer provides the primitives for self-organization, routing and resource lookups. The self-organization property brings the operational costs to minimum by eliminating the need for monitoring and maintenance activities, which traditional infrastructures require.
SIP Thor is designed to automatically recover from disasters like network connectivity loss, server failures or denial of service attacks. On node failure, all requests handled by the faulty node are automatically distributed to surviving nodes without any human intervention. When the failed node becomes available, it takes back its place in the network without manual interaction.
Traditional technology duplicates functionality and wastes resources by using expensive and inefficient hot/stand-by clusters. SIP Thor uses all available servers in active mode to their maximum capacity. With SIP Thor, there is no need for expensive hardware or stand-by machines to achieve high-availability distributed among different geographic sites. Capacity can be increased by simply adding extra nodes. Just by installing a standard software package, a new node is able to take its place in the network without any manual configuration.
SIP Thor architecture is described here.