In this paper, the problem of connection provisioning with QoS guarantees is studied in DiffServ/MPLS over optical networks. In most previous studies, the objective is to provide bandwidth guaranteed LSPs, without considering service differentiation. In practice, to guarantee QoS for some class of services in a DiffServ scenario, other constraints besides bandwidth should be enforced on the LSP and the network. We discuss these constraints and take them into account in the routing procedure. The simulation results show that QoS is guaranteed at the cost of higher bandwidth blocking probability, and an appropriate preemption mechanism is indispensable in the DiffServ/MPLS over optical networks.
This paper proposes a collision-free access protocol based on scalable slotted ring network architecture. Multiple QoS classes are supported directly in optical layer. The Qos scheme adopts the fixed home slots strategies to satisfy the requirements of services. Furthermore, efficient slot reuse is proposed. Simulation results show that the protocol can achieve good performance to guarantee the quality of traffic.
A new flexible broadcast optical switching structure (FBOSS) using tunable optical splitter is proposed. FBOSS supports both point-to-point and point-to-multipoint (broadcasting) connections, and any input optical signal can be broadcasted to any number of output optical ports without extra optical power loss. Its flexibilities of the optical port and optical wavelength help to enhance the capability of switching.
Since optical ring is the main topology in metro ring, it is essential to study on the medium access control protocol. In this paper, medium access control protocols in metro optical ring are discussed. We firstly classify the current protocols, then analyze performance requirements and technology attributes thoroughly. At last, several topics remained to be studied are presented.
A novel all-optical packet switching is presented. Adopting optical-controlled optical switch and multi-wavelength optical label technology, all the extraction of optical packet header, recognizing of route information and control of optical switch matrix can be processed in optical domain without O-E/E-O conversion. In this switching, the header label pulses are separated to different optical paths to control the optical-controlled optical switch matrix. According to different sequence and different wavelength of the header pulses, the different optical routes can be established, and a kind of all-optical packet switching is achieved.
Since Resilient Packet Ring has been the subject of intense research, it is necessary to study and analyze the performance of technology. In this paper, based on queuing theory and M/G/1/K queuing system, the average packet transfer delay following Darwin preliminary draft is analyzed. The results show that high priority traffic gets the lowest delay and the difference between medium and low priority traffic is small. In addition, the larger the network, the less is the difference. Maximum network throughput is also obtained in theory, which is instructive to further promote the related standard and even to design network in practice.
In order to improve the processing ability in the switching node, a lot of optical packet switching schemes were proposed, one of them is multi-wavelength label switching. In the scheme, a case of using K bit-long label and W different wavelengths can obtain WK unique labels at most. Here A novel label-coding scheme was put forward, which can produce more labels than before, For an example, if using 2 bit-long label and 2 different wavelengths, we can get 9 different labels, instead of 4 different labels using the old coding method proposed in the paper. At last, we give the design of the transceiver in detail.
The realization technology of a new kind of multi-wavelengths label optical packet switching technology is discussed. In this switching, optical header is labeled by several optical pulses at different wavelengths in the same optical communication channel band as optical payload. The optical transmitter with header generation and packet formation, receiver with data restoration and switching node with route processing are introduced. The switching principle is verified by a simplified experiment.
The recent increase in the transmission speed and bandwidth has resulted in the emergence of new networking solution, Resilient Packet Ring. In this paper, we firstly study the spatial reuse protocol in Resilient Packet Ring. Then based on node model, we discuss several access control mechanisms, including traffic shaping and Virtual Destination Queuing. Finally, a new effective fairness algorithm is presented. In order to ensure the requirement of high priority traffic and avoid high priority traffic taking up all of capacities, the algorithm proportionally assigns the fair rate to different traffic in a theoretical optimal way according to the service priority.
Coarse wavelength-division multiplexing (CWDM) is an ideal solution to the tradeoff between the cost and the capacity. Compared with DWDM, CWDM system deploys uncooled distributed feedback (DFB) lasers and wideband optical filters. These technologies provide several advantages to CWDM systems such as lower power dissipation, smaller size and less cost. For these merits mentioned above, the CWDM system will be widely used in the metro and access networks in the future. The CWDM system is scalable, but the scalability is limit. So, in some metro networks, it can¡¯t meet the increasing needs of the capacity. To solve this problem, there are a few of solutions proposed now, such as the TDM techniques and the combination with the DWDM that is applied in C band. In this paper, firstly, we will introduce the techniques of the CWDM, and explain the reasons of the less cost, and then the solutions to the scalability are presented in detail. At last we introduce the applications in the metro and access networks at present.