Architecture for restorable call allocation and fast VP restoration in mesh ATM networks

This paper presents architecture for restorable call allocation and fast vi rtual path (VP) restoration in mesh ATM networks. In this architecture, vir tual working and spare capacities needed for call allocation and restoratio n are reserved and released dynamically on a call-bg-call basis at the time of call admission and termination, This obviates the need for advance assi gnment of spare and working capacities. To shorten the call processing dela y, this is done in parallel-distributed fashion. To provide restorable call allocation, parallel-distributed Call processing algorithms of sender-choo ser type are suggested. The algorithms integrate, on the call level, virtua l bandwidth allocation, virtual spare-capacity assignment, and fixed, alter nate, or state-dependent routing. Each routing scheme leads to a particular tradeoff between call processing complexity, call setup delay, and bandwid th efficiency. For each pair of nodes, two sets of VP's are provisioned, Th e first, working VP (WVP) set, is used for call allocation during the norma l operation. The second, spare VP (SVP) set, is used for WVP restoration in the event of failures of network elements. Each SVP protects a preassigned subset of the node pair's WVP's. Each SVP is selected to be link/node disj oint from the WVP's that it is assigned to protect, This assures a protecti on of the WVP set by a small number of SVP's, Since SVP's are preset and ap propriate virtual spare capacities are reserved in advance, the architectur e guarantees full restorability and provides very fast restoration. The res toration is done on the VP level in a self-healing manner. The suggested ar chitecture requires only local, information to be maintained at each node.