Dynamic Routing in Circuit-Switched Networks

摘要

More and more network providers have decided to abandon the hierarchical, fixed alternate-routing methods and are instead planning to introduce dynamic non-hierarchical routing for their transit networks. Real-time traffic control through dynamic routing has become a means of efficient handling of unplanned and forecast traffic variations. It is therefore worthwhile to investigate and compare the properties of the different dynamic-routing methods proposed by network providers. Methods such as Northern Telecom's dynamically controlled routing (DCR), AT&T's real-time network routing (RTNR), British Telecom's dynamic alternative routing (DAR) and NTT's state and time dependent routing (STR) are examples of proposed or already implemented dynamic-routing methods. The authors describe the above-mentioned routing methods and some other approaches towards dynamic routing. They focus on questions concerning network efficiency and resilience for the less complicated methods, compared with the centralised/distributed methods that use extensive network intelligence. The required processor capacity and the possibility of using analytical methods are also discussed.