This PDF file contains the front matter associated with SPIE Proceedings Volume 8310, including the Title Page, Copyright information, Table of Contents, Introduction (if any), and the Conference Committee listing.

We propose a novel optical multicast tree design algorithm for hierarchical optical path networks that exploit waveband routing. To efficiently groom wavelength multicast trees into waveband trees, we define a generalized inclusive relation between node groups that identifies neighboring destination groups. The algorithm then establishes a minimum weight waveband tree that contains the wavelength multicast trees that include the neighboring destinations. Numerical experiments confirm that the proposed waveband multicast can significantly reduce the number of optical switch ports.

Various broad bandwidth services have being swallowing the bandwidth resource of optical networks, such as the data center application and cloud computation. There are still some challenges for future optical networks although the available bandwidth is increasing with the development of transmission technologies. The relationship between upper application layer and lower network resource layer is necessary to be researched further. In order to improve the efficiency of network resources and capability of service provisioning, heterogeneous optical networks resource can be abstracted as unified Application Programming Interfaces (APIs) which can be open to various upper applications through Application-oriented Integrated Control Center (AICC) proposed in the paper. A novel Openflow-based unified control architecture is proposed for the optimization of cross layer resources. Numeric results show good performance of AICC through simulation experiments.

A Dynamic clustering scheme based on coordination of management and control is proposed to reduce network congestion rate and improve the blocking performance of hierarchical routing in Multi-layer and Multi-region intelligent optical network. Its implement relies on mobile agent (MA) technology, which has the advantages of efficiency, flexibility, functional and scalability. The paper's major contribution is to adjust dynamically domain when the performance of working network isn't in ideal status. And the incorporation of centralized NMS and distributed MA control technology migrate computing process to control plane node which releases the burden of NMS and improves process efficiently. Experiments are conducted on Multi-layer and multi-region Simulation Platform for Optical Network (MSPON) to assess the performance of the scheme.

An architecture of wavelength division multiplexing (WDM) optical packet switching (OPS) router with all-optical regenerators is proposed. The regenerator based on phase-sensitive amplifier (PSA) can simultaneously provide phase and amplitude regeneration for quadrature phase-shift keying (QPSK) or differential quadrature phase-shift keying (DQPSK) signals. The simulation results show that three regenerators are sufficient for an OPS router in a node with a nodal degree of five to keep blocking probability below 5% and throughput ratio above 95% under different intensities of self-similar traffic load.

We propose a hierarchical optical path network design algorithm that considers wavelength conversion. Numerical experiments prove that, by employing wavelength conversion, hierarchical optical path networks will be more cost effective than single-layer optical path networks over a wide range of traffic demand, which is not possible without using wavelength conversion.

Bandwidth-variable (BV) optical networks have obvious advantages to provide spectrum-efficient transportation. Previous research showed that the BV-supported adaptive routing (AR-BV) had lower blocking probability than the BV-supported fixed routing (FR-BV), when signaling blocking is not considered. In order to study the overall blocking probability, we propose a BV extension to RSVP-TE signaling protocol, and implement it on our large-scale ASON test-bed. Results show that due to the flooding process, AR-BV has a higher signaling blocking probability compared with the FR-BV, especially in a highly dynamic network scenario, and this weakens its advantage in overall blocking performance.

The routing and spectrum assignment (RSA) is one of the key problems in flexible optical networks. When in a gridless fashion, the shortest-path RSA algorithms have exponential computational complexity, and are thus not suitable to be employed in real networks. On the other hand, today most optical components cannot support fully gridless tunability, which also limits the application of gridless RSA schemes. In this paper, we propose a novel grid-based spectrum-scan routing (SSR) scheme in flexible optical networks. The SSR scheme achieves optimal routing with a polynomial computational complexity. Compared with other RSA schemes, SSR has shorter computation time, lower blocking probability, and higher resource utilization.

Physical layer of high-end network system uses multiple interface arrays. Under the load-balancing perspective, light load can be distributed to multiple interfaces. However, it can cause energy inefficiency in terms of the number of poor utilization interfaces. To tackle this energy inefficiency, traffic off-balancing algorithm for traffic adaptive interface sleep/awake is investigated. As a reference model, 40G/100G Ethernet is investigated. We report that suggested algorithm can achieve energy efficiency while satisfying traffic transmission requirement.

We propose network design algorithms to minimize the power consumption of a translucent optical network with joined optimization of mixed regenerator placement and wavelength assignment. The performance of the algorithms is investigated with simulations in ring and grid network topologies. Simulation results indicate that the algorithms can effectively reduce the number of O/E/O 3R regenerators, leading to less power consumption on signal regeneration and green network design. Among the algorithms, the maximum segment length wavelength assignment(MSL-WA) approach further reduces regenerator numbers, with the cost of placement readjustments.

This paper presents a comprehensive tool based planning process of optical networks to solve the problems from strategy to implementation, especially for brown-field planning with network merge, migration or convergence. Referring to cross layer design, this planning strategy is proposed for fixed and mobile convergence from IP networks to transports networks. The importance of a tool support is verified for strategic planning, detailed design and implementation. In addition, two case studies from previous projects are discussed to identify the planning issues and the efficiency of this approach.

We show that OFS suffers from the long-flow short-flow (LFSF) unfairness problem especially for single wavelength network, and this problem becomes even more severe for the real-world self-similar Internet traffic. By segmenting the long flows into many short flows and scheduling the transmission dynamically, the LFSF unfairness can be reduced significantly. By combining the segmentation strategy with the previously proposed virtual output queuing (VOQ) scheduling approach, it is shown that the throughput of OFS network under self-similar traffic can be improved from 25% to 85% for the single wavelength case, and from 55% to over 90% for the multi-wavelength case.

The lightpaths within a wavelength switched optical network (WSON) are usually bi-directional, with a same route and a same wavelength which are allocated for both directions from the viewpoint of optical network operation. On the other hand, the introduction of generalized multi-protocol label switching (GMPLS) as a network control plane is expected to bring more intelligence and to provision the end-to-end lightpath in a cost-efficient manner. In this paper, we experimentally demonstrate and evaluate dynamic provisioning of bidirectional lightpaths in GMPLS controlled optical networks, considering the wavelength continuity constraint and the physical impairment constraint on both directions.

A technique using artificial neural networks trained with parameters derived from reconstructed eye diagrams for optical performance monitoring in 40-Gbps optical duobinary (ODB) system is demonstrated. Firstly, the optical signal is asynchronously sampled by short pulse in the nonlinear medium such as semiconductor optical amplifier and highly nonlinear fiber, the sampled and collected data is then processed by improved software synchronization algorithm to obtain reconstructed eye diagrams without data clock recovery. Secondly, the features of the reconstructed eye diagrams are extracted to train the three-layer preceptor artificial neural network. Finally, the outputs of trained neural network are used to monitor multiple optical signal impairments. Simulation experiments of optical signal noise ratio (OSNR), chromatic dispersion (CD) and polarization mode dispersion (PMD) monitoring in 40-Gbps ODB system is presented. The proposed monitoring scheme can accurately identify simultaneous impairment with the root-mean-square (RMS) monitoring error less than 3%.

In this paper, we introduce our Home2015 project - wavelength-agile optical access networking system. We propose a multi-wavelength access network to offer higher system capacities for next-generation optical access. Our proposed concept of virtual PON (VPON) is introduced to realize dynamic ONU re-grouping functionality. Optical network units (ONUs) in the PON system can dynamically form different TDM-PON by using a different downlink and uplink wavelength channel. Novel photonic silicon chip integration techniques are introduced to reduce size and cost of the ONUs. We also introduce our works on live 3D hologram video transmission platform design and live 3D hologram video transmission via the 10-Gb/s wavelength-agile optical access network. Our demostration shows that our system has good transmission performances.

In this paper, we investigate the capital and operational expenditures for two next generation optical access (NGOA) networks based on wavelength division multiplexing (WDM) technology in dense urban areas. It is shown that with a proper fiber layout design, minor extra investment for protection of NGOA networks can make a significant saving on failure related operational cost.

In this paper we present a solution for providing protection in a Ethernet based access and metro network. To accomplish this we targeted two issues, protection aimed path computation in networks which does not provide fully disjoint paths, and the design and implementation of bi-directional forward detection (BFD) protocol in a GMPLS controlled Ethernet network. To the best of our knowledge, neither issue has been previously addressed through a similar approach and is therefore to be considered novel in its design and implementation. Our implementation shows good performances and reliability in both performance testing and testbed experiments.

With rapid growth of Internet applications, supporting differentiated service and enlarging system capacity have been new tasks for next generation access system. In recent years, research in OFDMA Passive Optical Networks (PON) has experienced extraordinary development as for its large capacity and flexibility in scheduling. Although much work has been done to solve hardware layer obstacles for OFDMA PON, scheduling algorithm on OFDMA PON system is still under primary discussion. In order to support QoS service on OFDMA PON system, a novel dynamic wavelength bandwidth allocation (DWBA) algorithm is proposed in this paper. Per-stream QoS service is supported in this algorithm. Through simulation, we proved our bandwidth allocation algorithm performs better in bandwidth utilization and differentiate service support.

We have proposed to use a directly modulated tunable fiber ring laser based on reflective semiconductor optical amplifiers(RSOA) and tunable optical filter (TOF) as an upstream source in multi-wavelength shared(UMWS) time division multiplexing-passive optical network (TDM-PON) configuration. Downstream signal is broadcasted in TDM way while upstream signals are multiplexed in hybrid time/wavelength division multiplexed way, which upgrades the upstream capacity greatly. Bidirectional transmission of downstream data at 10-Gb/s and upstream data at 1.25-Gb/s per wavelength over 25-km single mode fiber (SMF) is demonstrated with a power penalty of ~0.5 dB at both ends. A stable performance is observed for the upstream wavelength tuned from 1530 nm to 1595 nm.

We propose an advanced algorithm to achieve coordinated CMTS-side energy-saving in a HFC network supporting DOCSIS 3.0 standard. Based on traffic information, the algorithm grooms as many as cable modems (CMs) on a minimal number of CMTS ports as possible, and put the rest of its ports to sleep for energy-saving. With network simulations using a realistic CM traffic model, we demonstrate over 31.5% saving on the ON-time for CMTS ports. We also investigate the tradeoff between the energy-saving and the number of CM change operations, and the results show that the algorithm can control the number of CM changes with a preset readjustment threshold.

Exploiting anycast routing significantly reduces optical network and server energy usage. In this work we present a case study showing that intelligently selecting destinations and routes thereto, while switching off unused (network) elements, cuts power consumption by around 20% and saves network resources by 29%.

Since the underlying demand for network capacity can be satisfied only by extremely increasing transmission bit rate, processing speed, and switching capacity, it definitely will lead to increased power consumption of network nodes. Energy crisis is global crisis nowadays and it has brought up many problems. Power consumption is becoming a crucial issue in designing high-performance network devices. This paper studies the power consumption model of a kind of Optical Packet Switching (OPS) node based on Semiconductor Optical Amplifiers (SOA). Our results show that by dynamically adjusting the bias current of SOAs, the power consumption on an OPS node can be reduced considerably, especially when the traffic distribution across multiple ports is not balanced and inter-nodal distances vary. The total electrical power consumption can be cut off significantly. We also show the power consumption can be further reduced by jointly optimizing the thermoelectric cooler current.

This paper describes an inter-domain path control system for large-scale photonic networks, especially considering applicability to multiple carrier domain networks. The overall architecture of multi-domain optical network control system is reviewed. Our system employs PCE (Path Computation Element) based routing model and utilizes maximum flow information in path computation and Path Key scheme in signaling, which improve the load-balancing and the confidentiality of the inside information for the route computation and the path provisioning among different carriers. The measured performance results for inter-domain path computation and path setups using global optimization scheme is also provided. It includes estimation of the path provisioning time at the network scale dependency with the route computation time and the signaling time. As a result, its applicability to a 1000-node scale photonic network is shown.

The traditional approach for inter-domain Traffic Engineering Label Switching Path (TE-LSP) computation like BRPC could provide a shortest inter-domain constrained TE-LSP, but under wavelength continuity constraint, it couldn't guarantee the success of the resources reservation for the shortest path. In this paper, a Collision-aware Backward Recursive PCE-based Computation Algorithm (CA-BRPC) in multi-domain optical networks under wavelength continuity constraint is proposed, which is implemented based on Hierarchical PCE (H-PCE) architecture, could provide an optimal inter-domain TE-LSP and avoid resources reservation conflict. Numeric results show that the CA-BRPC could reduce the blocking probability of entire network.

Point-to-Multipoint (P2MP) services in optical networks are more and more important for high-capacity applications. Steiner tree algorithms have been investigated to compute minimum-cost multicast tree. However, it is difficult to compute an optimal P2MP tree in multi-domain networks because of isolation of each domain. There are several algorithms based on Path Computation Element (PCE) for computing multi-domain Point-to-point path, but computing P2MP Traffic Engineering Label Switched Path (TE-LSP) in a multi-domain networks is still a challenge. In this paper, three PCE-based schemes for P2MP inter-domain LSP computation are compared in full splitting capability networks, and a novel Multi-Domain Minimum-cost Path Heuristic (MDMPH) algorithm is proposed. Simulation results proved that the MDMPH algorithm computes P2MP tree with less cost than the other three schemes.

A network using minimum set of nodes and links that all communication data traffics among nodes can be carried while meeting the QoS requirements named MiDORi (Multi- (layer, path, and resources) Dynamically Optimized Routing) has been proposed. MiDORi network technologies that is composed of a low energy consumption network design tool (MiDORi path computation engine (PCE)), MiDORi Generalized Multi-Protocol Label Switching (GMPLS) protocol extensions for controlling network equipment, and a MiDORi router/switch controlled by MiDORi GMPLS, are now developing. This paper describes recent activities of the MiDORi network technologies.

We consider an energy-aware WDM core network, where the electric prices differ according to time intervals of the day, referred to as time-of-use rates. Since a large backbone network may have nodes scattered over several time zones, we exploit the time-of-use rates to lower the electric bill of the network provider. By using an ILP formulation of the bill minimization problem, we investigate the gain of total electric bill over two approaches where capacity and energy are optimized under different network traffic load conditions.

This paper evaluates power efficiency of TE link dormant mode in optical transport network, considering daily traffic variability and GMPLS protocol. The proposed TE link dormant mode tries to let data links comprised the TE link transfer into the dormant state according to several selection criteria considering either the power consumption parameter of each link and their positioning in the network topology. The total energy saving is 35% on the energy efficient WSON test bed.

In this paper the history of channel speed development of optical transport networks, from a few MbI/s to beyond 100 GbI/s, is reviewed. A new channel type categorization, which divided various channel designs into only three basic channel types, has been proposed. Based on the new categorization distinguishable performances of the three types of channels are analyzed and the future direction of optical channel designs is predicted.

In order to meet various bandwidth requirements, such as sub-wavelength and super-wavelength, and overcome the power consumption bottleneck, dynamic flexible optical networks have become the middle term solution of all optical networks instead of optical packet switching (OPS) networks. Different from routing and wavelength assignment (RWA) in WDM networks, routing and spectrum assignment (RSA) in dynamic flexible optical networks faces more constraints, which are summarized as three-C constraints, i.e. Continuity, Consistency, and re-Configurability. Routing and spectrum assignment problem in three-C-aware dynamic flexible optical networks is mainly investigated in the paper. Keywords: Flexible optical networks, three-C, routing and spectrum assignment, defragmentation.

In the field of cloud computing over optical networks, virtualization is an important issue. Typically this can be implemented on hardware or software. In this paper, we propose an infrastructure-as-a-service (IaaS) framework-OptoVisor, with optical network virtualization implemented on management plane. This framework provides flexible resource scheduling and monitoring. Then we show the viability of our proposal with experimental demonstration and performance test.

Due to the growing demand of flexible resource management for cloud computing services, researches on live virtual machine migration have attained more and more attention. Live migration of virtual machine across different hosts has been a powerful tool to facilitate system maintenance, load balancing, fault tolerance and so on. In this paper, we use a measurement-based approach to compare the performance of two major live migration technologies under certain network conditions, i.e., VMotion and XenMotion. The results show that VMotion generates much less data transferred than XenMotion when migrating identical VMs. However, in network with moderate packet loss and delay, which are typical in a VPN (virtual private network) scenario used to connect the data centers, XenMotion outperforms VMotion in total migration time. We hope that this study can be helpful in choosing suitable virtualization environments for data center administrators and optimizing existing live migration mechanisms.

A very important issue in executing a scientific workflow in optical grid is how to map the workflow tasks onto multiple distributed resources. In this paper, we propose a new cost-based workflow scheduling algorithm (MCBS) which tries to minimize the cost of the workflow execution while meeting the deadline defined by users. The simulation results prove the efficiency of the MCBS algorithm.

We proposed a dynamic routing and frequency slots allocation scheme which adopted the adaptive modulation for a novel Spectrum-sLICed Elastic optical path network (SLICE). In our dynamic routing scheme, both spectrum resource availability (SRA) and distance (hop number) are considered at the modulation format selection phase for adaptive modulation. We then conducted numerical simulation to compare our Spectrum Resource Adaptive and Distance Adaptive (SRA-DA) mechanism with previous DA in both small network topology and 7×7 mesh topology. Results shown that SRA-DA mechanism achieved lower blocking rate and higher slots utilization compared to DA in bigger networks.

This paper studies the dynamic Routing and Spectrum Assignment (RSA) problem in Bandwidth Flexible Optical networks. We propose a k-path Signaling-based RSA scheme and simulation results show that it performs much better than other RSA schemes in Bandwidth Flexible Optical networks.

Orthogonal Frequency Division Multiplexing (OFDM) has recently been proposed as a modulation technique. For optical networks, because of its good spectral efficiency, flexibility, and tolerance to impairments, optical OFDM is much more flexible compared to traditional WDM systems, enabling elastic bandwidth transmissions, and optical networking is the future trend of development. In OFDM-based optical network the research of blocking rate has very important significance for network assessment. Current research for WDM network is basically based on a fixed bandwidth, in order to accommodate the future business and the fast-changing development of optical network, our study is based on variable bandwidth OFDM-based optical networks. We apply the mathematical analysis and theoretical derivation, based on the existing theory and algorithms, research blocking probability of the variable bandwidth of optical network, and then we will build a model for blocking probability.

High data rates employed in transparent optical networks (TONs) demand reliable transmission between node pairs realized through different protection and restoration schemes. Besides component faults causing node or link failures, services may also be disrupted by certain malicious attacks which target the vulnerabilities of TON physical-layer components, such as high-powered jamming. The consequences of such attacks can differ significantly from component faults, so classical techniques used for protection may not necessarily guarantee survivability against them. To provide attack-aware protection in TONs, we develop a dedicated path protection algorithm in which we identify the so-called attack groups of each primary and backup path and perform RWA in a way which ensures that they are attack groupdisjoint.

A new scheme of optical LSP parallel resource reservation based on PCE architecture is proposed to minimize the adverse effect from wavelength continuity constraint when provisioning lightpath in WDM optical networks. Lightpath setup delay and blocking probability are prominently decreased, evaluated by simulations.

In wireless optical broadband access network (WOBAN), when a new session was established, some links probably overlapped the existing session, which leaded to congestion. To reduce the blocking probability in the overlapped links, a routing algorithm named ILCA (Integrated Least Congestion Algorithm) was designed. This algorithm integrated both multichannel technology at the wireless domain and wavelength division multiplexing at the optical domain, in which the relative queue length (RQL) in the wireless domain and RB (residual bandwidth) in the optical domain were adopted to evaluate the congestion. Simulation results showed that ILCA could enhance WOBAN throughput compared with SMIRA_1 and SPR.

Optical circuit-switched networks can offer end-to-end dedicated connection with high-capacity bandwidth for largescale applications, but end-systems' performance in these applications often becomes the bottleneck of bulk data transfer in ultra-high-speed network. We propose a bandwidth scheduler based on the end-systems' effective transfer rate and study its performance through experiment.

An enhanced dynamic wavelength and bandwidth allocation (DWBA) algorithm in hybrid WDM/TDM PON is proposed and experimentally demonstrated. In addition to the fairness of bandwidth allocation, this algorithm also considers the varying propagation delays between ONUs and OLT. The simulation based on MATLAB indicates that the improved algorithm has a better performance compared with some other algorithms.

We address the problem of content delivery network for HD-VoD service. Content delivery network (CDN) is a network that puts users closer to the storage resources. The conventional CDN structure for video delivery is based on the IP-over- WDM network which could not meet the requirements for HD-VoD service, such as high-speed transfer and low latency and jitter. A novel all-optical CDN network model for high-definition VoD service is proposed in this paper. We introduce the concept of optical timeslot in the lightpath provision. A mini-control plane mechanism based on ring topology is also designed for the fast optical timeslot setup/release. Simulation results and analysis of our model is showed at the end of paper.

Reliable service delivery becomes more significant due to increased dependency on electronic services all over society and the growing importance of reliable service delivery. As the capability of PON increasing, both residential and business customers may be included in a PON. Meanwhile, OPEX have been proven to be a very important factor of the total cost for a telecommunication operator. Thus, in this paper, we present the partial protection PON architecture and compare the operational expenditures (OPEX) of fully duplicated protection and partly duplicated protection for ONUs with different distributed fiber length, reliability requirement and penalty cost per hour. At last, we propose a differentiated protection method to minimize OPEX.

A novel restoration scheme for multi-failures based on protection ring with dynamic weight (PRDW) is proposed in this paper. This scheme effectively resolves the multi-failures which is in one service and the conflicts by restoration between services. PRDW use Dijkstra's algorithm to compute path and protection ring. These rings rely on protection weight which is dynamic, so that they can as much as possible to divide multi-failures to single ones. Meanwhile PRDW introduce independent protection weight to balance load, which effectively gets combat for resources less vicious. Simulation results show that PRDW works better than traditional schemes.

Ant Colony Optimization (ACO) is a popular research field these years. Ants choose paths where pheromone concentration is higher and modify the environment they visited. However, in the context of multi-service in multi-level and multi-domain optical network, the capacity of inter-domain links is limited. Congestion may be occurred at inter-domain links. In this paper, ant colony optimization algorithm based on load balancing is proposed. Ants follow paths not just depend on pheromone alone, we also take available resources on the link as a factor too. Simulations show the proposed method could reduce the traffic blocking probability, and realize load balancing within the network.

We study the impact of light path routing on network survivability and present a Single-Node Failure Algorithm based on current IP over WDM static topology mapping methods. The goal of the algorithm is to map the IP topology links into light paths in WDM topology to ensure IP topology remains connected after the failure of a single node in WDM topology.

In this paper, we propose a colorless, directionless and contentionless (C/D/C) ROADM architecture using bandwidth variable carriers select switches (BV-WSS) for elastic optical network and illustrate various advantages offered by it. We also discuss some extensions for current control plane of ASON framework.

Flexible bandwidth networking has recently been proposed as a spectrally efficient networking technology that effectively supports dynamically varying traffic demands [1]. This networking technology provides an opportunity to maximize spectral efficiency for each of many arbitrary bandwidth channels generated using one of many possible modulation formats [2]. Path Computation Element (PCE) is first introduced for dynamic routing and spectrum assignment problem in elastic optical network. We proposed three centralized and distributed routing and spectrum assignment solutions. They are Centralized Routing and Distributed Spectrum Assignment (CR+DSA), Centralized Routing and Centralized Spectrum Assignment (CR+CSA) and Distributed Routing and Distributed Spectrum Assignment (DR+DSA). The two centralized proposals both own PCE in its architecture. The performance of three proposed centralized and distributed routing and spectrum assignment solutions have been analyzed and compared. For the experimental evaluation, the performance of Centralized Routing and Centralized Spectrum Assignment is the most adaptable RSA strategy for the whole bandwidth-variable optical networks with dynamic traffic.

In this paper, a novel survivable algorithm with dynamic load balancing shared-path protection is proposed, named DLBSPP algorithm, in spectrum-elastic optical path networks (SLICE). To tolerate multi-link failures in SLICE, traffic self-adaptive restoration (TSAR) mechanism is adopted to restore the traffic affected by the failures. Simulation results show that, compared with the conventional SPP algorithm, DLBSPP algorithm has lower blocking probability (BP), better spectrum utilization ratio (SUR) and higher failure restoration ratio (FRR).

The OFDM-based mm-RoF technique emerges the possibility of cost-effective and high data rate ubiquitous wireless networks. However, due to the existence of the nonlinear effects, the performance of OFDM-based mm-RoF meets the limitations. In this paper we analyses the improved performance of a 16QAM-OFDM mm-RoF with predistortion design.

Transparent optical network is now becoming increasingly attractive, but transparency will induce security threats, e.g. high-powered jamming attack, in optical networks. In this paper, we proposed a new attack model, named JAP-model, for attack-aware routing and wavelength assignment heuristics in transparent optical networks. In JAP-model, gain competition attack and inter-channel crosstalk attack imposed by the propagation effect of intra-channel crosstalk attack are also considered. Lower block probabilities are obtained using the model.