2002 - cesnet

The logical core topology anticipates the establishment of three basic rings of Prouters, connected through a pair of central routers. Each logical ring will connectnot more that four P routers. We have set this number with respect to thedynamic behaviour of the network (particularly the packet delay) and the convergenceof internal router protocols (quick convergence of the internal routingin case of a change). The used interface types and the transfer to GE will notenable the use of more effective and faster mechanisms for the traffic rerouting(Fast Rerouting, DPT) where the rerouting time is approximately 50 ms. In addition,we expect significant technological changes to be carried out within thedefined rings.During the second half of the year, tender procedures were carried out for thesupplies of gigabit PE routers. The procedures also included tests for verifyingthe functions declared by the manufacturer and testing of compatibility with theexisting Cisco technology (GSR 12016 and OSR 7609).According to the size of the GigaPoP, we divided the required configurationsof routers into three categories. The categories differ in the required numbersHradec KrálovéOstravaLiberecnorthringwestringPrahaBrnoÚstí n. L.PlzeňsouthringP router (core)PE router (access)České BudějoviceFigure 3.6: Planned logical topology of network coreHigh-speed National Research Network and its New Applications 200225