A New Hybrid Alarm Correlation Scheme For MPLS-Enabled Backbone Networks

Service providers have been in the process of evaluating and evolving their multiple networks to a single converged Internet Protocol (IP)-based infrastructure upon which they will deploy existing and future services. Although many approaches have been proposed, provisioning of Quality of Service (QoS) in the IP-based networks is still a challenging task. From the evolution of QoS solutions, Differentiated Services (DiffServ) appears to become the mainstream QoS solution. Using service differentiation principle, DiffServ approach for providing QoS omits the integration with other traffic control mechanisms. Multi-Protocol Label Switching (MPLS) complements DiffServ providing mechanisms to choose and reserve resources on the best available path for a given traffic. This paper discusses the MPLS DiffServ integration to achieve QoS in IP-based networks and to illustrate its effectiveness by performing a simulation using Network Simulator (ns-2).

Forward error correction (FEC) techniques are essential for optical core and optical access networks. In optical core networks, the emphasis is on high coding gains and extremely low output bit error rates, while allowing decoder realizations to operate at a throughput of 100 Gb/s and above. Optical access networks operate at 10 Gb/s or above and require low-complexity FEC codes with low power consumption. Coherent optical transmission with higher order modulation formats will become mandatory to achieve the high spectral efficiencies required in next-generation core networks. In this paper, we provide an overview of these requirements and techniques, and highlight how coding and modulation can be best combined in optical core networks. We also present guidelines for modulation and low-complexity FEC system design for optical access networks.

Fast setup of end-to-end paths for bandwidth constrained applications in an IP/MPLS–ATM integrated environment

We consider an IP/MPLS over WDM network, in which label switched routers (LSRs) in the IP/MPLS layer are interconnected through optical cross-connects (OXCs) in the optical core network (WDM layer) providing an end-to-end wavelength routing capability. In this paper, we study a dynamic label switched path (LSP) routing problem for the three different network models of the IP/MPLS over WDM network, namely, Overlay, Augmented, and Peer models. For the overlay model, we propose two algorithms: ECF_OVLY and MLH_OVLY. In ECF_OVLY, a network always tries to use existing capacity first, whereas in MLH_OVLY, a network finds a path with the minimum number of logical hops for an LSP request. We also propose, for the augmented model, two simple and efficient dynamic LSP provisioning algorithms, called MCPI_AUG and DCPI_AUG, utilizing different type/amount of summarized capacity information from the WDM layer, namely Minimum CaPacity Information (MCPI) and Detailed CaPacity Information (DCPI). We compare the proposed algorithms with the existing algorithms available for the overlay [1] and peer [2], [3] models. The algorithms are compared and evaluated using two key performance measures: LSP blocking probability and network (lightpath) utilization. Simulation results show that at low loads with a limited number of ports available in the network, DCPI_AUG achieves an order of magnitude better blocking performance than the algorithm in [2] and outperforms the one in [3] by more than three times. It also achieves higher network utilization than the one in [2] by more than 10 % and the one in [3] by 2-7 % depending on the traffic load. Considering the small amount of information that is exchanged between the layers in the augmented model, these results suggest that the augmented model can be a practically good compromise between the overlay and peer models.

In this paper, we examine the QoS issues in the intelligent optical network (ION), and specially focus on the QoS implementation scheme associated with the control plane. Referring to the QoS models in IP networks, we propose the optical IntServ QoS model using in metropolitan optical networks, and the optical DiffServ QoS model using in core optical networks. The networks to support optical IntServ QoS model must deal with each traffic request for QoS assurance, then compute routes and establish lightpaths. In the optical DiffServ QoS model, core networks only accept the limited classes of QoS requests. Therefore traffic flows with similar QoS requirements from the metropolitan networks must be aggregated, and then core networks provide tunnels for them. It increases the scalability of networks. In the end, this paper presents the generalized control plane architecture of the node in ION, which is based on extended GMPLS and able to guarantee subscriber’s QoS using two optical QoS models.

1 - The Big Picture

The growing energy consumption has posed new challenges for the future development of networks. Some earlier work has proposed solutions to improve energy consumption based on the existing control plane, for example, node/links sleeping. This study presents a new possibility to reduce network energy consumption by proposing a new integrated control plane structure utilising Software Defined Networking technologies. The integrated control plane increases the efficiencies of exchanging control information across different network domains, while introducing new possibilities to the routing methods and the control over quality of service (QoS). The structure is defined as an overlay generalised multi-protocol label switching (GMPLS) control model. With the defined structure, the integrated control plane is able to gather information from different domains (i.e. optical core network and the access networks), and enable energy efficiency networking over a wider area. In the case presented, the integrated control plane collects the network energy related information and the QoS requirements of different types of traffic. This information is used to define the specific group of traffic's (flow's) routing behaviours. With the flexibility of the routing structure, results show that the energy efficiency of the network can be improved without compromising the QoS for delay/blocking sensitive services.

Optical networks—the electro-optic reality

In this paper, we present a novel networking technique based on optical Multi-Band Orthogonal Frequency Division Multiplexing (MB-OFDM). We highlight the interesting features of the solution with respect to existing ones (fully opaque optical networks and transparent networks) for optical metro and core networks. We show that under certain traffic condition MB-OFDM may offer useful flexibility in the context of increasing wavelength bit rates.

Optical connectors are used in a widespread application range, from low-cost automotive networks with polymeric fibers to multi-fiber single-mode connectors in optical glass fiber core networks. In this chapter, either single-fiber or multi-fiber connectors are described. Different types of single-mode and multi-mode connectors are currently available on the market. A description about the used types is included. In the second section of the chapter, the production and quality control of optical fiber tapers are represented.

At present there are some worm detection systems, primarily for a single LAN or with hardware router environment, which main use worm propagation characteristics for detection and has high false alarm rate, but it is not applicable for large-scale network for detecting. This paper presents a distributed worm detection technology, which is divided into two parts, client end and the console end program. The system uses the rule-based detection methods to monitor network worms, and the console side manages and coordinates the multiple side work of detecting. Experimental results show that the method can be good applicable for worms conduct surveillance based on a single or multiple local area network and is used for worm alarming, the method has high detection rate and low false alarm rate.

Optical burst switching (OBS) is a switching technology that can efficiently operate in the optical core network using WDM technology and can also develop the future optical internet. The OBS switching technology presents a trade-off between the two switching technologies: optical circuit switching (OCS) and optical packet switching (OPS). This switching approach increases resource utilization compared with OCS technology and avoids the technological barriers of OPS networks. In OBS networks, many packets are assembled into one data burst at the edge node and a burst header packet (BHP) is sent before the burst transmission by an offset time in order to reserve the required resources in core nodes. This can cause security issues in the network and more specifically denial of service attacks that can occur if a source node is compromised. In this paper, we study a specific denial of service attack which we refer to as "BHP flooding attack", which prevents legitimate traffics from reserving the required resources at intermediate core nodes. We also propose the design of a reconfigurable BHP flooding countermeasure module that allows to counter against this type of attacks in an OBS network.

The Internet generation infrastructure is growing and moving towards a consistency model of high-speed nodes interconnected by optical core networks. Therefore, the interaction between IP and optical network layers, specifically, the routing and signalling aspects, are maturing and they can lead to enhance the services and network performance. At the same time, a consensus has emerged in the industry on utilizing IP-based protocols for the optical control plane. This paper defines a new technique for IP over Optical networks (interacting between bottom layers), considering both the IP-based control plane for optical networks as well as IP-optical network interactions (together referred to as “IP over optical networks”). In this paper, a new technique is proposed that reduces recovery time by making an interoperation between the data link layer (layer 2) with the network layer (layer 3). The proposed technique enables layer 2 with layer 3 to make a hybrid mechanism that improves the recovery time in the network through two cases (1st-Detection and 2nd-Rerouting). The technique involves detecting failure in less time through layer 2 and rerouting traffic through an alternative path between source and destination by using a new algorithm in layer 3 to deliver data packets without the need to wait for the routing protocol to update the network topology and compute the routing table. In case of the network recovery, layer 2 has demonstrated its capability to detect failure extremely quickly shown through the immediate detection of the loss of signals for the link or node. The recovery mechanism, i.e., the rerouting mechanism, which leads the node, switches the data packets through an adjacent node to its destination via the life node. The latter is created by the proposed mechanism before the occurrence of the failure. The aim of this mechanism is to avoid loss of packets, improve QoS and improve recovery time as we have shown in the results shown below.

Higher spectral efficiency and greater data rate per channel are the most cost-effective strategies to meet the exponential demand of data traffic in the optical core network. Multilevel modulation formats being spectrally efficient enhance the transmission capacity by coding information in the amplitude, phase, polarization or a combination of all. This paper presents the design architecture of a 32-channel dense wavelength division multiplexed (DWDM) system, where each channel operates with multi-level phase modulation formats at 40 Gbps. The proposed design has been simulated for 50 GHz channel spacing to numerically compute the performance of both differential phase-shift keying (DPSK) and differential quadrature phase-shift keying (DQPSK) modulation formats in such high-speed DWDM system. The transmission link is analyzed with perfect dispersion compensation and also with under-compensation scheme. The link performance in terms of quality factor (

It is widely believed that IPTV will be one of the major applications in future IP networks and that IP over optical networks will be a major component of the next generation Internet. However, it is not efficient to map a single multicast IPTV flow into one light tree because the required bandwidth of an IPTV flow is usually much less than the capacity of a light-tree. Furthermore, pay-per-view or secure flows should be sent only to authorized users. In this paper, we study the problem of multi-class multicast flow aggregation with the constraint that secure programs are sent to authorized nodes. We first describe the problem and prove it to be NP-complete. We then formulate an integer linear program (ILP) and give results for small scale problems. Heuristic algorithms are presented, and results show that our heuristics achieve good results in both small and large scale problems. Also simulations show that the ratio of secure programs over total programs has great impact on the final aggregation results.