Tunable QoS-Aware Network Survivability Presenter : Yen Fen Kao Advisor : Yeong Sung Lin 2013 Proceedings IEEE INFOCOM Agenda Introduction Model and Problem Formulation The Structure of CT Solutions Establishing QoS Aware p-Survivable Connections Simulation Study A Network Design Perspective Conclusions 2 Introduction Any failure in the network infrastructure may lead to a vast amount of data loss. Survivability in the network is becoming important. 3 Introduction Two major classes of recovery schemes 1. Restoration schemes 2. Protection schemes This paper adopt the widely used single link failure model. 1. simplicity 2. protecting against a single failure is a common requirement of various standards 3. multiple failures is to supply protection for the first failure and restoration for any subsequent ones 4 Problems Under the single link failure model, the employment of disjoint paths provides full (100%) protection. The requirement of fully disjoint paths is often too restrictive and demands excessive redundancy. A pair of disjoint paths of sufficient quality may not exist. More flexible survivability concept is called for. 5 Introduction A previous study introduced the novel concept of tunable survivability. Provides a quantitative measure to specify the desired level of survivability. 6 7 Introduction p -survivable Is a probability of at least p to have all common links operational during the connections lifetime. 8 Introduction Distinguish between two classes of QoS metrics 1. bottleneck metrics 2. additive metrics The important and much more complex class of additive metric was not considered. 9 Example p -survivable connections combining an additive QoS metric 10 Introduction Motivate investigate how to combine the tunable survivability concept with additive QoS guarantees. Agenda Introduction Model and Problem Formulation The Structure of CT Solutions Establishing QoS Aware p-Survivable Connections Simulation Study A Network Design Perspective Conclusions 11 Model and Problem Formulation 12 13 Model and Problem Formulation 14 Model and Problem Formulation Single link failure model considers handling at most one link failure in the network Classified 1. faulty 2. operational 15 Definition 16 Definition 17 Definition Define weight 1. minimum of the lengths of two paths => NP-complete 2. worst(highest) among the weights of the two paths => NP-Hard Adopt minimize the aggregate weight of the two paths 18 Definition 19 Definition Agenda Introduction Model and Problem Formulation The Structure of CT Solutions Establishing QoS Aware p-Survivable Connections Simulation Study A Network Design Perspective Conclusions 20 21 Definition 22 Theorem 23 Agenda Introduction Model and Problem Formulation The Structure of CT Solutions Establishing QoS Aware p-Survivable Connections Simulation Study A Network Design Perspective Conclusions 24 25 Establishing QoS Aware p-Survivable Connections Solution approach is based on a graph transformation. => Restricted Shortest Path(RSP) problem RSP problem is the problem of finding a shortest path while obeying an additional constraint. 26 CO-QoS Aware Max Survivable Connection(CO-QAMSC) Algorithm E mploys two well-know algorithm 1. Edge-Disjoint Shortest Pair(EDSP) algorithm 2. Pseudo-polynomial algorithm scheme Pseudo-Polynomial Schemes for CO-QAMSC 27 Pseudo-Polynomial Schemes for CO-QAMSC 28 Pseudo-Polynomial Schemes for CO-QAMSC 29 Similar to the CO-QAMSC Algorithmic Two important changes 1. Transformation of simple links in the new constructed network 2. Stage 0 finds a weight-shortest path in the network G(V,E) by employing a well-known shortest path algorithm Pseudo-Polynomial Schemes for CT-QAMSC 30 Pseudo-Polynomial Schemes for QoS Aware Survivable Connections 31 Example Agenda Introduction Model and Problem Formulation The Structure of CT Solutions Establishing QoS Aware p-Survivable Connections Simulation Study A Network Design Perspective Conclusions 32 33 A modest relaxation, of a few percent in the survivability level, is enough to provide significant improvement in terms of delay. Agenda Introduction Model and Problem Formulation The Structure of CT Solutions Establishing QoS Aware p-Survivable Connections Simulation Study A Network Design Perspective Conclusions 34 35 Discovering the in-all-weight-shortest-paths links Finds a weight-shortest path by employing a well-known shortest path algorithm. Consider a replica of the original network excluding the link of weight-shortest path. Find in the replica network a weight-shortest path. If the replica weight is greater than original, then exclude original link belong to the in-all-weight-shortest-paths links set. If equal, then the excluded original link does not belong to the set. Repeated for all links of the weight-shortest path of the original. 36 Optimal Links Upgrade Problem M The problem can be transformed into an instance of Water-filling problem. To repeatedly split the upgrade budget among the links of the in-all- weight-shortest-paths link set with the highest failure probability, until eight the budget is exhausted or all the links assume zero failure probability. Agenda Introduction Model and Problem Formulation The Structure of CT Solutions Establishing QoS Aware p-Survivable Connections Simulation Study A Network Design Perspective Conclusions 37 38 Conclusions Established efficient algorithmic schemes for optimizing the level of survivability while obeying an additive end-to-end QoS constraint. Characterized a fundamental property, by which the links that affect the total survivability level of the optimal routing paths belong to a typically small subset. Demonstrated the advantage of tunable survivability over traditional survivability schemes. 39 Further The actual deployment of the tunable survivability approach. This study provides evidence to the profitability of implementing this novel concept, as well as useful insight and building blocks towards the construction of a comprehensive solution. Thanks for your attention