Efficient dynamic routing in Spectrally-Spatially Flexible Optical Networks based on traffic categorization and supervised learning methods

In this paper we focus on the efficient dynamic routing in spectrally-spatially flexible optical networks (SS-FON). To this end, we propose novel adaptive spectral-spatial allocation (ASSA) algorithm supported by high load spectral-spatial allocation (HLSSA) mechanism. The main principle of the ASSA/HLSSA is to allow for demand allocation using spectral-spatial channels only in the case of high network load while prioritizing channels using lowest possible number of spatial modes. Then, we evaluate efficiency of the proposed approach by means of extensive numerical experiments. The results show its high efficiency especially for sets of relatively big demands and in a survivable network (in that case protected by dedicated path protection). According to the experiments, the methods allow to reduce bandwidth blocking probability up to 5.5% comparing to the allocation without their application.

Broadcast TV distribution over an IP network requires stringent QoS constraints, such as low latency and loss. Streaming content in IPTV is typically delivered to distribution points on an IP backbone using IP multicast protocols such as Protocol Independent Multicast Source Specific Mode (PIM-SSM). Link-restoration using MPLS or layer-2 Fast Reroute (FRR) is a proven failure restoration technique. Link-based FRR creates a pseudo-wire or tunnel in parallel to the IP adjacencies (links); and thus, single link failures are transparent to the Interior Gateway Protocol (IGP) such as OSPF. Although one may choose the back-up path's IGP link weights to avoid traffic overlap during any single physical link failure, multiple failures may still cause traffic overlap with FRR. We present a cross-layer restoration approach that combines both FRR-based restoration for single link failure and “hitless” (i.e., without loss) PIM tree reconfiguration algorithms to prevent traffic overlap when multiple failures occur.

Message transformation and routing is one of the core functions provided by Enterprise Service Bus (ESB). However, most of the current ESB software can only provide static configurable routing patterns, and some dynamic message routing patterns can not ensure the reliability and efficiency at the same time. In order to overcome these issues in the ESB, this paper proposes an Efficient and Reliable Dynamic Service Routing (ERDSR) pattern by using abstract routing table and abstract routing path. This dynamic message routing pattern mainly solves two issues: how to promote efficiency by modifying the path contents which is stored in the abstract routing table and how to re-locate service providers when they have problems.

A resource-efficient provisioning framework (RPF) is proposed in this paper for optical networks providing dedicated path protection (DPP) and shared path protection (SPP) services. The framework reduces resource consumption by considering spare capacity reservation of DPP and SPP cooperatively while provides 100% survivability guarantee and maintains the recovery time for both protection types against the predominant single link failures. To tackle the service provisioning problem under the framework, an integer linear programming (ILP) formulation is presented to find the optimal routing solution for a given set of traffic demands. The objective is to minimize total capacities consumed by working and backup paths of all demands. Then, heuristics are developed for on-line routing under dynamic change of traffic. Numerical results show that compared with traditional provisioning framework (TPF), the RPF has the following advantages: (1) Over 10% capacity savings are achieved for static service provisioning; (2) blocking probability of both protection types is greatly reduced; (3) lower resource over build is achieved; and (4) average backup-path hop distance of shared-path-protected flows is reduced. Finally, network survivability in face of double link failures is discussed under the framework.

A wireless sensor network (WSN) consists of low power, low cost, limited memory and small in size sensor nodes, organise them in a cooperative network and perform three basic operations - sensing data from environment, computation, and data routing. Routing in WSN mainly focuses on data dissemination, data aggregation, life time of the network and limited bandwidth constraints in order to facilitate the efficient working of the network. Due to the limited battery power, the energy conservation is a critical aspect to design an efficient routing protocol in WSN. This paper proposes the energy efficient dynamic and self-optimised routing to prolong the life time of the network, QoS and solve the stagnation problem in the network.

Elastic optical networks are seen as a promising solution to improve spectrum utilization efficiency by utilizing flex-grid optical orthogonal frequency division multiplexing technology and facilitating flexible bandwidth allocation to services with heterogeneous demands. With dramatic growth of Internet traffic and imminent fiber capacity exhaustion, multiple fibers per link are required to accommodate increasing demands. In this paper, we investigate path selection and spectrum management for heterogeneous bandwidth requests by taking the network topology and expected traffic pattern into account. A novel and efficient solution for path selection and spectrum assignment that optimizes the state of the network after assignment is proposed. We first develop integer linear programming formulations to calculate path selection probabilities offline. Then, we propose a spectrum partition scheme that provides a particular spectrum range for each request size. A next-state-aware spectrum assignment algorithm with resource sharing among partitions is then introduced. We use the demand blocking ratio for dynamically arriving requests as the performance indicator. Simulation results indicate the effectiveness of our proposed schemes for routing and spectrum assignment, as they perform 1 to 2 orders of magnitude better than several baseline schemes.

A mobile ad hoc network is a network of mobile nodes connected by multi-hop wireless links without centralized infrastructure support. The area of ad hoc networking is receiving increasing attention in recent years. Efficient dynamic routing is an important research challenge in such a network. In recent years, routing has been the most focused area in ad hoc networks research. On-demand routing, in particular, is widely developed in bandwidth constrained mobile wireless ad hoc networks because of its effectiveness and efficiency. A variety of new multipath routing protocols targeted at the ad hoc networking environment have been proposed. Multipath routing improves the throughput of ad hoc networks; it is a straightforward mechanism to recover from route losses in a dynamic network. In this paper we have considered a very well-known multipath routing protocol called ad hoc on-demand multipath distance vector routing (AOMDV) on both MAC layers, the standard IEEE 802.11 and a TDMA MAC protocol called evolutionary-TDMA (E-TDMA). We have evaluated the performance of these multipath routing through simulations using NS2 varying the number of paths (particularly we have considered 2 and 3 paths) and varying the number of temporary colors.

Network survivability has become a crucial requirement in all types of computer networks. It becomes even more significant for wavelength division multiplex (WDM) mesh networks due to their high speed and capacity. These networks are prone to link failures. A link failure may be a single or multiple link failure. A single-link failure is easy to locate and fix as compared to multiple link failures. A dual-link failure recovery technique has been proposed using p-cycles. This technique uses a replication method for the p-cycle circle. It is an enhancement of the original failure independent path protection p-cycle scheme. The replica properties of p-cycle have been used to protect the nodes through the same p-cycle available. Creating a new p-cycle always adds to the cost of the network, whereas using a replica of already existing p-cycle significantly reduces the network cost. The proposed technique is implemented using network simulator in three phases.

Network virtualization has been put forward as a promising way to run multiple virtual networks (VNs) simultaneously on a shared physical network. As single physical failure can bring down the services of multiple VNs, the problem of efficiently mapping VNs to a physical network while guaranteeing the survivability of VNs has become an increasingly important issue. In this paper, we propose a novel survivable multi-domain VN embedding approach against single link failure. Specifically, we first investigate the visibility of VN Providers on physical network resources and topology for VN splitting. Then we present a framework for multi-domain VN embedding that comprises a set of operations. Moreover, we enhance the survivability of VNs by guaranteeing the sustaining connectivity for VNs against single link failure, and formulate the survivable inter-domain embedding problem as an integer linear programming. Simulation results demonstrate the effectiveness and efficiency of our algorithm.

This paper presents an application of Artificial Bee Colony (ABC) algorithm for survivable optical network design. The dedicated path protection (DPP) survivability scheme is modelled by ABC algorithm for establishing two link-disjoint paths between each node pair in demand matrix considering single link failure scenarios. In the proposed algorithm every food source represents a lightpath between each node pair in optical network and the position of food sources are modified by artificial bees to minimize the total number of utilized wavelengths by working and spare lightpaths. Simulation results demonstrate that the proposed ABC based survivability scheme is able and efficient to design fault-tolerant optical transport networks.

In this paper, we investigate efficient approaches and algorithms for protecting multicast sessions against any single link failure while establishing multicast sessions in WDM mesh networks. Since a single failure may affect whole nodes in a multicast group and causes severe service disruption and a lot of traffic loss, protecting critical multicast sessions against link failure such as fiber cut becomes important in WDM optical networks. One of the most efficient algorithms is optimal path pair-shared disjoint paths (OPP-SDP). In this algorithm every source-destination (SD) pair has the optimal path pair (working and protection path) between the source and destination node. Since degree of sharing among the paths is essential to reduce the total cost and blocking probability, we propose the longest path first-shared disjoint paths (LPF-SDP) algorithm which decides the priority of selection among SD pairs in a resource-saving manner. Our LPF-SDP is shown to outperform over OPP-SDP in terms of degree of sharing and blocking probability.

Empowered by the rapid advancement of fiber optic sensing techniques in recent years, network carriers are able to upgrade their network infrastructure beyond the basic communication services with extra sensing applications and services (e.g., monitoring traffic and road condition, leakage detection, etc.), thus evolving to a new era of Infrastructure-as-a-Sensor (IaaSr) or Network-as-a-Sensor (NaaSr). When network carriers upgrade their network infrastructures with distributed fiber optic sensing (DFOS) technique to provide IaaSr services, there will arise a critical challenge: how to provide survivable (or reliable) IaaSr services against network failures (e.g., fiber cut). In this work, for the first time, we investigate the problem of survivable DFOS placement against single link failure. More specifically, we study where to place the primary and backup sensors and how to assign the primary and backup fiber sensing routes, with the objective of minimizing the number of sensors used. We formulate the problem using Integer Linear Programming (ILP) to facilitate the optimal solution. In addition, we propose a set of efficient heuristic algorithms to solve the problem in a fast manner. In particular, the proposed Shared-one algorithm provides a cost-efficient shared protection, through a one-step global optimization of the assignment of primary and backup DFOS placement. We conduct extensive simulations to evaluate the performance of the proposed solutions. We find out that Shared-one can achieve a close-to-optimal performance, compared to the ILP optimal results, while outperforming the other heuristic solutions with an average performance improvement by at least 16%.

Fast-recovery from link failures is a well-studied topic in IP networks. Employing fast-recovery in Ethernet networks is complicated as the forwarding is based on destination MAC addresses, which do not have the hierarchical nature similar to those exhibited in Layer 3 in the form of IP-prefixes. Moreover, switches employ backward learning to populate the forwarding table entries. Thus, any fast recovery mechanism in Ethernet networks must be based on undirected spanning trees if backward learning is to be retained. In this paper, we develop three alternatives for achieving fast recovery from single link failures in Ethernet networks. All three approaches provide guaranteed recovery from single link failures. The approaches differ in the technologies required for achieving fast recovery, namely VLAN rewrite or mac-in-mac encapsulation or both. We study the performance of the approaches developed on five different networks.

The p-cycle survivable network design under the single link failure assumption has been studied extensively. Shared risk link group (SRLG) is a concept that better reflects the nature of network failures. An SRLG is a set of links that may fail simultaneously because of the common risk they share. The capability of dealing with SRLG failures is essential to network survivability. In this paper, we extend the p-cycle design from the single link failure model to the single SRLG failure model. An integer linear programming (ILP) formulation that minimizes spare capacity requirement is provided. To avoid enumerating all cycles of a network, we also provide an algorithm to generate a basic candidate p-cycle set that guarantees 100 % restorability in case of a single SRLG failure given enough spare capacities. Simulation results of optimal p-cycle design under the single SRLG failure model are presented. The spare capacity efficiency performance of the basic candidate p-cycle set is also evaluated. Finally, we give a brief overview of the SRLG failure detection problem and its impact on the restoration speed which is an important consideration of p-cycle design.

This paper introduces an efficient implementation of the network coding-based 1+N protection. The strategy provides proactive protection to N link-disjoint full-duplex connections against single link failures. The implementation is efficient and uses a tree shaped minimum cost protection circuit. The protection circuit carries linear combinations of data units originally transmitted on the working circuits, and these linear combinations can be used to recover data units lost due to failures. This recovery is carried out with the assistance of one node on the protection tree, which is chosen to reduce the recovery time. This protection technique requires the same amount of protection resources used by 1:N protection, where the protection circuit is link disjoint from the protected connections. The paper also makes other contributions. It introduces an Integer Linear Program (ILP) formulation to evaluate the cost of protection using this technique, and compares it to the cost of 1+1 protection. The comparison shows that a significant saving in cost can be achieved, while recovering from failures within a short time. The performance of this scheme is further evaluated using an OPNET-based simulation, where it was shown that the recovery time conforms to acceptable industry standards. Availability analysis is also conducted.