With the continuous progress of science and technology and the rapid development of the Internet, higher requirements have been put forward for network performance. EONs (Elastic Optical Networks) is proposed as an optical network with high reliability, high efficiency and high survivability. Although there have been many researches on EONs and various performance indexes, it is still a problem how to evaluate the comprehensive ability of optical networks comprehensively. This paper designs a network design scheme evaluation model based on AHP (Analytic Hierarchy Process) and business priority. According to the evaluation results, different protection schemes are adjusted, which provides valuable reference for the construction of network planning scheme. The basic performance index is obtained according to the scheme and network planning algorithm, and the survival performance index is obtained according to the protection algorithm. AHP was used to establish the hierarchical structure model for these two categories, paired comparison matrix was constructed through the comparison of two performance indicators, consistency test was conducted, and the final weight was calculated. Finally, according to the weight of the total order of the weighted hierarchical weighted calculation, the final decision basis. Multiply the weight of the decision by 100 to get a percentage score. Based on the score, it can determine whether the solution is suitable, and then adjust the business priority and network design solution, as well as provide effective reference for network planning.
With the popularization of emerging services such as 5G, cloud computing, the backbone network traffic has grown rapidly and the network running state will change frequently. Unfortunately, the unrelated development of the IP layer and the optical layer in the existing network leads to lack of flexibility in services and makes the hardness and cost of the overall operation and maintenance of the backbone network higher and higher. although the IP layer and the optical layer are converged, due to the uncertainty and unpredictability of the IP business itself, the lack of dynamic interaction mechanism between the two layers becomes increasingly prominent. Therefore, this paper proposes a new NSE-RFC (a network operation state evaluation algorithm based on random forest classification) algorithm, which provides a scientific and comprehensive evaluation of network running state. The results show that the correct rate of the algorithm is 97.5%, which can accurately evaluate the network running status. Finally, the validity of the model is verified by the consistency of the evaluation results of the model and the variation of the time distribution characteristic map of each evaluation index.
This paper presents a path and algorithm scoring method, which can quantitatively evaluate the degree of optimization and intelligently alert potential problems to realize automatic planning and maintenance of optical networks. Since the development of the networks, there is a growing demand for high speed, low latency, and low power consumption. Path selection has always been a problem that needs to be considered in detail in network communication. The combination of classical graph theory and continuously developed algorithms makes algorithms appear constantly. It is found that the increase in the number of services makes the high separation between the actual paths and optimal paths. Combining the scores, we can allocate routing and spectrum for different types of services, meanwhile the average running time of a single service performs lower using the path and algorithm scoring method, which will save a lot of processing time. The result of the simulation shows that as the number of services increases, the scoring method has a clear advantage in processing services. According to this method, a data foundation can be provided for automatic optimization threshold monitoring for operators to adjust the network in advance.
With the rapid development of mobile Internet, the business volume continues to increase, which puts forward higher requirements for carrying network. As the current mainstream load carrying network scheme, IPRAN network conforms to the load carrying requirements of various services, not only adapting to base station transmission, but also compatible with multi-service comprehensive transmission. Different networking schemes will lead to great differences in cost. How to design the lower cost IPRAN networking scheme rapidly while meeting the business requirements has always been the concern of telecom operators. This paper presents a cost optimization scheme based on IPRAN networking. Based on the actual situation of BBU and RRU distribution in the region to be planned, we designed the access scheme for RRU with the aim of minimizing the sum of lines between BBU and RRU, so as to ensure the lowest line cost. In addition, we propose two constraints, namely, the number of comprehensive service access nodes on each comprehensive service access ring and the number of centralized BBU on each comprehensive service access node. Under the two constraints, we choose the scheme with the lowest equipment cost. Finally, we conducted simulation on the algorithm proposed in this paper, and the results showed that: for IPRAN networks with less than 1000 base stations, this algorithm could select the scheme with the lowest equipment cost from many schemes within 0.7 seconds, and meanwhile give the line design scheme with the least optical fiber loss, providing reference for IPRAN network.
This paper proposes an access network requirements analysis method based on similar service feature values clustering. The network service feature values data are collected from the real access network, including devices and users’ information. The K-means ++ algorithm is adopted to cluster the PON ports, based on the similar service feature values of users connected to them. 3 classifiers are selected for classification training and prediction. They are K-nearest neighbors, SVMs and perceptron. In the case of no clustering, K-nearest neighbor algorithm performs better, and the classification correct rate is about 91.1%. And if the data is divided into 5 groups by K-means++ algorithm, it can be calculated that the average accuracy is 94.3%. Compared with the result without clustering of service feature values, it achieves more accurate prediction and the correct rate is increased by 3.3%. With this method, the operator can determine whether the PON port needs to be expanded, making the expansion planning more forward-looking. At the same time, combining the prediction results with the PON port geographic information, it can distinguish areas with sufficient or insufficient broadband resources, and helps operators adjust service allocation plans to match user needs.
The 5G bearer network consists of three parts: pre-transmission, intermediate transmission, and backhaul transmission. The integrated service access node bearer devices can aggregate the pre-transmitted traffic to the wireless devices of the node, and can also upload the intermediate/backhaul services to the upper-layer bearer devices. The integrated service access node requires a rich access service types and high requirements for bandwidth and delay. Packet enhanced OTN (POTN) can well meet above requirements. IP Radio Access Network (IPRAN) has been widely used in 4G bearer network. In order to achieve intelligent upgrade of the network, the POTN+IPRAN scheme came into being. For each operator, it is necessary to reduce the construction cost of the bearer network while meeting the needs of new services and new scenarios in the future. In this paper, we design a cost-minimized algorithm for POTN device in POTN+IPRAN 5G bearer network (CM_POTN). We set two constraints, they are the number of centralized BBUs on each integrated service access node and the number of integrated service access nodes on each integrated service access ring. For the purpose of minimizing the cost of POTN devices, the algorithm attempts to calculate the minimum cost of the main component modules in the POTN devices within the two constraints. Moreover, a simulation is designed to evaluate the performance of the proposed algorithm, and results show that our proposed CM_POTN algorithm can achieve the minimum cost of the POTN devices within the given constraints.
Network failures are unavoidable and can easily cause huge losses. The occurrence of failures typically results in a number of changes that have to be made to recovery and keep operating the network in a normal manner. Restoration is a common method of network failure recovery. However, the traditional methods of Path Restoration and Link Restoration will be effective only when there are resources that can satisfy the condition in the network. And the resource utilization is not high enough. We propose a network failure recovery method based on reinforcement learning, integrated Path Restoration and Link Restoration. The protection channel of the damaged service flow and the channel of the normal service flow share the bandwidth resource. A simulation is designed to evaluate the performance of the proposed algorithm. Simulation shows that whether there is only one input service flow or multiple input service flows, when the final switched flow cannot find a suitable path in the idle resource, the traffic of the best situation will be the minimal of all possible cases. The scheme of this paper can effectively improve the success rate of network failure recovery with high utilization of physical resources. It is more extensive than traditional methods.
With the information flow in the network growing rapidly and the size of network extending gradually, it is essential that SDON networking supports multi-domain optical services. Since the type of network has moved toward complicated and converged, the disparate network resource has interlaced, an isomerized network situation is the trend in the future. Accordingly, end-to-end (E2E) services have shifted from a single service provider domain towards a multi-domain service provider. On this condition, the traditional isolated networking mode is so difficult to meet the current demand. E2E multi-domain services are the trend in the future. This paper proposes a multi-domain service dispatching scheme based on SDON virtualized network. By sending concurrent http requests to controller multiple single-domain controllers, web service management will manage optical devices and achieve E2E multi-domain service requests over this scheme. The management layer establishes E2E services dispatching system in multi-domain virtual optical network and it changes the present situation of disparate single service provider incompatibility. The experiment also indicates the reality possibility of the multi-domain dispatching scheme. This scheme will provide basis for the large scale multi-domain networking based on SDON in the future.
The rapid growth of IP traffic has contributed to the wide deployment of optical devices (ROADM/OXC, etc.). Meanwhile, with the emergence and application of high-performance network services such as ultra-high video transmission, people are increasingly becoming more and more particular about the quality of service (QoS) of network. However, the pass-band shape of WSSs which is utilized in the ROADM/OXC is not ideal, causing narrowing of spectrum. Spectral narrowing can lead to signal impairment. Therefore, guard-bands need to be inserted between adjacent paths. In order to minimize the bandwidth waste due to guard bands, we propose an effective distance-adaptation traffic dispatching algorithm in IP over optical network based on SDON architecture. We use virtualization technology to set up virtual resources direct links by extracting part of the resources on paths which meet certain specific constraints. We also assign different bandwidth to each IP request based on path length. There is no need for guard-bands between the adjacent paths on the virtual link, which can effectively reduce the number of guard-bands and save the spectrum.
With the development of large video services and cloud computing, the network is increasingly in the form of services. In SDON, the SDN controller holds the underlying physical resource information, thus allocating the appropriate resources and bandwidth to the VON service. However, for some services that require extremely strict QoT (quality of transmission), the shortest distance path algorithm is often unable to meet the requirements because it does not take the link spectrum resources into account. And in accordance with the choice of the most unoccupied links, there may be more spectrum fragments. So here we propose a new RMLSA (the routing, modulation Level, and spectrum allocation) algorithm to reduce the blocking probability. The results show about 40% less blocking probability than the shortest-distance algorithm and the minimum usage of the spectrum priority algorithm. This algorithm is used to satisfy strict request of QoT for demands.
Virtual optical networks (VONs) have been considered as a promising solution to support current high-capacity dynamic traffic and achieve rapid applications deployment. Since most of the network services (e.g., high-definition video service, cloud computing, distributed storage) in VONs are provisioned by dedicated data centers, needing different amount of bandwidth resources in both directions, the network traffic is mostly asymmetric. The common strategy, symmetric provisioning of traffic in optical networks, leads to a waste of spectrum resources in such traffic patterns. In this paper, we design a holding-time-aware asymmetric spectrum allocation module based on SDON architecture and an asymmetric spectrum allocation algorithm based on the module is proposed. For the purpose of reducing spectrum resources’ waste, the algorithm attempts to reallocate the idle unidirectional spectrum slots in VONs, which are generated due to the asymmetry of services’ bidirectional bandwidth. This part of resources can be exploited by other requests, such as short-time non-VON requests. We also introduce a two-dimensional asymmetric resource model for maintaining idle spectrum resources information of VON in spectrum and time domains. Moreover, a simulation is designed to evaluate the performance of the proposed algorithm, and results show that our proposed asymmetric spectrum allocation algorithm can improve the resource waste and reduce blocking probability.
Software Defined Optical Network (SDON) can be considered as extension of Software Defined Network (SDN) in optical networks. SDON offers a unified control plane and makes optical network an intelligent transport network with dynamic flexibility and service adaptability. For this reason, a comprehensive optical transmission service, able to achieve service differentiation all the way down to the optical transport layer, can be provided to service function chaining (SFC). IP over optical network, as a promising networking architecture to interconnect data centers, is the most widely used scenarios of SFC. In this paper, we offer a flexible and dynamic resource allocation method for diverse SFC service requests in the IP over optical network. To do so, we firstly propose the concept of optical service function (OSF) and a multi-layer SFC model. OSF represents the comprehensive optical transmission service (e.g., multicast, low latency, quality of service, etc.), which can be achieved in multi-layer SFC model. OSF can also be considered as a special SF. Secondly, we design a resource allocation algorithm, which we call OSF-oriented optical service scheduling algorithm. It is able to address multi-layer SFC optical service scheduling and provide comprehensive optical transmission service, while meeting multiple optical transmission requirements (e.g., bandwidth, latency, availability). Moreover, the algorithm exploits the concept of Auxiliary Graph. Finally, we compare our algorithm with the Baseline algorithm in simulation. And simulation results show that our algorithm achieves superior performance than Baseline algorithm in low traffic load condition.
With the development of big data and cloud computing technology, the traditional software-defined network is facing new challenges (e.i., ubiquitous accessibility, higher bandwidth, more flexible management and greater security). Using a proprietary protocol or encoding format is a way to improve information security. However, the flow, which carried by proprietary protocol or code, cannot go through the traditional IP network. In addition, ultra- high-definition video transmission service once again become a hot spot. Traditionally, in the IP network, the Serial Digital Interface (SDI) signal must be compressed. This approach offers additional advantages but also bring some disadvantages such as signal degradation and high latency. To some extent, HD-SDI can also be regard as a proprietary protocol, which need transparent transmission such as optical channel. However, traditional optical networks cannot support flexible traffics . In response to aforementioned challenges for future network, one immediate solution would be to use NFV technology to abstract the network infrastructure and provide an all-optical switching topology graph for the SDN control plane. This paper proposes a new service-based software defined optical network architecture, including an infrastructure layer, a virtualization layer, a service abstract layer and an application layer. We then dwell on the corresponding service providing method in order to implement the protocol-independent transport. Finally, we experimentally evaluate that proposed service providing method can be applied to transmit the HD-SDI signal in the software-defined optical network.
With the rapid growth of 4G mobile network and vehicular network services，mobile terminal users have increasing demand on data sharing among different radio remote units (RRUs) and roadside units (RSUs). Meanwhile, commercial video-streaming, video/voice conference applications delivered through peer-to-peer (P2P) technology are still keep on stimulating the sharp increment of bandwidth demand in both business and residential subscribers. However, a significant issue is that, although wavelength division multiplexing (WDM) and orthogonal frequency division multiplexing (OFDM) technology have been proposed to fulfil the ever-increasing bandwidth demand in access network, the bandwidth of optical fiber is not unlimited due to the restriction of optical component properties and modulation/demodulation technology, and blindly increase the wavelength cannot meet the cost-sensitive characteristic of the access network. In this paper, we propose a software defined multi-OLT PON architecture to support efficient scheduling of access network traffic. By introducing software defined networking technology and wavelength selective switch into TWDM PON system in central office, multiple OLTs can be considered as a bandwidth resource pool and support flexible traffic allocation for optical network units (ONUs). Moreover, under the configuration of the control plane, ONUs have the capability of changing affiliation between different OLTs under different traffic situations, thus the inter-OLT traffic can be localized and the data exchange pressure of the core network can be released. Considering this architecture is designed to be maximum following the TWDM PON specification, the existing optical distribution network (ODN) investment can be saved and conventional EPON/GPON equipment can be compatible with the proposed architecture. What’s more, based on this architecture, we propose a dynamic wavelength scheduling algorithm, which can be deployed as an application on control plane and achieve effective scheduling OLT wavelength resources between different OLTs based on various traffic situation. Simulation results show that, by using the scheduling algorithm, network traffic between different OLTs can be optimized effectively, and the wavelength utilization of the multi-OLT system can be improved due to the flexible wavelength scheduling.
Two distributed service provisioning schemes based on the traditional scheme is proposed to facilitate the collaboration
between traditional grid resource and optical networks. A Grid-based Reconfigurable optical network testbed is built to
validate and compare those schemes. The experiment results based on the testbed prove that the performance of multi
source multi path service provisioning scheme is better the traditional way. With the joint resource allocation, multi
paths can be built up, and user can get data resources quickly from separated servers with guaranteed bandwidth from
Currently, many large-scale, resource-intensive applications and services such as Grids supported only by high-performance,
highly distributed infrastructures are being developed. These ultra-broadband services have put forward
high requirements of end-to-end Quality of Service (QoS) and of dynamic resource management, which makes end-to-end
optical resource provisioning necessary. For this reason an intelligent optical access network which combines
advantages of Generalized Multi-Protocol Label Switching (GMPLS) and Passive Optical Network (PON) proposed here.
In our scheme, GMPLS is in charge of providing control plane to manipulate PON communication and introduce traffic
engineering, while PON technology such as WDM-PON is employed as data plane following the control of GMPLS. We
describe the architecture of proposed network and illustrate the concept of common GMPLS control plane shared by
both core and access network. Then the functional module of intelligent Optical Line Terminal (OLT) and Optical
Network Unit (ONU) has been discussed. Finally, QoS model for access network and entire scheme for end-to-end
optical service provisioning have been introduced in detail.
Passive optical network (PON) is viewed by many as an attractive solution to the last mile bottleneck, since it can
provide much higher bandwidth compared to the traditional
copper-based network. In the standard PON, there is only
one wavelength for upstream channel by time division multiplexing technology and another wavelength for downstream
channel using broadcasting and selective receiving. Therefore, it can not meet for bandwidth-intensive services emerging
recently. Fortunately, incorporating wavelength division multiplexing (WDM) technology in a PON (WDM-PON) can
employ several wavelengths for upstream channel and downstream channel separately, and provide much higher
bandwidth than the TDM-PON. So WDM-PON is considered to be the future-proof solution of access optical networks.
In this paper, the development trend of WDM-PON architecture is revealed, and some hot technical issues and prospects
are also present.
In the current broadband access networks, Gigabit Ethernet passive optical networks (GE-PON) have emerged as
a promising candidate for next-generation broadband access networks. As this technology evolves, the
development of efficient dynamic bandwidth allocation (DBA) algorithms has become a key concern.
Bandwidth allocation based on the TDM mechanism has been discussed to a great deal. And the dynamics of
network load has been detected by the network designers and researchers, thus, different kinds of resource
distribution schemes are deployed in the broadband passive optical network (PON). Resources schemes are
mainly designed to fulfill the task of allocate the bandwidth according to the requirements from the end-users,
concerning the priority of service and traffic-load. However, the total dynamics of traffic-load's priority can't be
determined precisely and there need to be a dynamic priority group based scheduling. This paper proposes a
novel dynamic bandwidth allocation scheme that exploits diff-group to implement the timeslot assignment
among ONUs with two-stage priority queuing to yield a globally optimized QoS control.
Ethernet PON (EPON) has been proved to be a successful technology among all the standardized PON systems [1, 2], in
terms of its cost-effective and large bandwidth virtue. And EPON has become a network of a choice for subscriber
oriented digital service delivery, taking over the market previously dominated by DSL. However, with the development
of advanced video services, the bandwidth capacity of current EPON seems to be not well suited for the future large
deployment of triple-play services. Many researches are now taken about the Next Generation EPON; and the recent 10G
EPON system standardization effort in the IEEE  results a lot of interest in the evolution of current PON systems
towards high data rate system capable of providing a future-proof platform for delivery of personalized triple-play
services. In this paper, a novel architecture of TDM-based 10GE-PON system is proposed. It combines the GE-PON and
10GE-PON systems, and provides symmetric 1Gbps/10Gbps or asymmetric access simultaneously. According to the
results of the simulation on the system throughput and latency performance, the system is verified to be one solution and
an important step from 1Gbit/s to 10Gbit/s for the Next Generation EPON.
The paper presents a novel WDM-PON architecture with converged TDM-PON and WIMAX to provide wired and
wireless services at a uniform platform. The QoS map mechanism at isomerous network with theory and simulation
comparison is given. As a novel of network architecture, this paper presents the basical survivability and reliability
With the fast development of optical network technologies, for dealing with the shortcoming of the traditional grid based
on the Internet, it is considered to introduce the optical network resource as one of grid resources in the control and
management of grid. So the idea of optical grid was proposed. This paper analyzes the characteristics of optical grid
differing from traditional grid. And then we propose a new transmission scheme applied in optical grid---multi-path
transport scheme. We compare and analyze its performance in the optical grid. Eventually we draw the conclusions.
This paper proposes a dynamic traffic sharing routing algorithm to balance the load of optical internet. By sharing traffic on 2 or 3 SRLG-disjointed paths, we improve the networks survivability. By adjusting the links' weights, the algorithm can avoid generating bottlenecks on shorter links. The simulation result shows that the network performance can be improved significantly by the DTS algorithm.
This paper investigates the function modules in ASON model, and analyzes the strategic planning process and the fundamental planning process in the ASON plan. To facilitate evaluation algorithms and technologies, we develop a visual simulation system for ASON modelling and planning and give a simple example of ASON planning case.
To provide visual communication over enterprise Intranet, the video conference system in H.323 has been proposed as a suitable architecture to take the place of circuit-switched telephony model. However, managing video conference system will be complicated due to the real-time monitoring and reporting. This paper presents some research on the network management of H.323 Video conference system, and introduces the standards about this system, such as ITU-T H.341 and H.350 recommendation, and then gives some advices on network management design for video conference system with the considering of the real-time feature.