Network Redundancy in URAN City Segments

P.A. Zhuravkov

Ukrainian Research and Academic Network, Politekhnichna 33, Kyiv, Ukraine

zhurav@uran.net.ua

In the current stage of URAN (Ukrainian Research and Academic Network) development reliability has become a very important issue. There are different reasons why outage can happen – our experience in URAN shows that power loss and link breakage (e.g. cable cut) are the most common, equipment failures are less. Every node of the network is equipped with UPS which can provide several hours of operation, but unfortunately sometimes this is not enough – URAN equipment is often installed in the university premises where high quality power supply is not available. To minimize negative consequences every URAN city segment has ring topology. There is one central node with routing and switching equipment where inter-city channel is terminated and several nodes with switching equipment for clients’ connections. To provide redundancy, Spanning Tree Protocol is used between all the switches so in case of long-term power loss on any node or cable cut connectivity between nodes remains. We use PC-based routers on central nodes. To provide redundancy for them we plan to implement CARP protocol which will provide failover redundancy in case if the main router goes down for some reason.