Abstract: With the dramatic increment and development of traffic on the backbone, it's impossible for the ISPs to upgrade their core routers frequently, and the scalability of the core routers becomes the key issue for protecting investment. As the scalability of traditional routers based on crossbar switch architecture is poor, the scalable distributed switch architecture must be adapted in terabit routers. Summary of the latest research achievements and the new features of terabit routers are discussed. Based on the study of three-dimensional ring architecture, three-dimensional torus architecture and multi-dimensional hypercube architecture, a thorough analysis of the distributed architecture utilized in modem terabit routers is presented. The prospect of terabit router was investigated.