Shu Du

Propagation of all-optical crosstalk attack in transparent optical networks

Transparent optical network (TON) is now rapidly booming to be popular, and a threat of an all-optical crosstalk attack with high power will emerge. In this paper, the penalty of crosstalk attack propagation, including intrachannel crosstalk inside the optical cross-connects, as well as direct and indirect interchannel crosstalk within fibers, is evaluated. Our work has proved that these crosstalk attacks do propagate in the TON but with limited propagation stages, which will be useful for the planning, management, and design of TON.

Power-efficient RWA in dynamic WDM optical networks considering different connection holding times

The challenges imposed by environmental issues, such as global warming and the energy crisis, are demanding more responsible energy usage, including in the optical networking field. In optical transmission networks, most of the electrical power is consumed by the optical-electrical-optical conversion in optical repeaters. Modern optical network control plane technologies allow idle optical repeaters to be put into a low-power sleep mode. Inspired by this, we propose a novel power-efficient routing and wavelength assignment (RWA) algorithm, called HTAPE. The HTAPE algorithm exploits the knowledge of the connection holding times to minimize the number of optical repeaters in the active mode, and hence reduce the total electricity consumption of the optical network. We test the new algorithm on the typical CERNET and USNET networks. Compared with traditional RWA algorithms without holding-time-awareness, it is observed that the HTAPE algorithm yields significant reductions in power consumption.

A novel segment-shared protection algorithm based on dynamic domain-sequencing scheme for multi-domain optical mesh networks

Survivability has been widely recognized as an important design issue for optical networks. In practice, as the network scale keeps expanding, this design problem becomes more critical. Due to scalability and domain privacy, designing the protection scheme in multi-domain networks is more difficult than that in single domain networks. The path computation element (PCE) is known as an efficient architecture to compute optimal traffic engineering (TE) paths in multi-domain multilayer networks. Based on the PCE architecture, we first propose a new dynamic domain-sequencing scheme that considers the load balance of inter-domain links and then propose an improved segment-shared protection approach called DDSP. It can provide 100% protection ability for multiple failures that each single domain has only one failed link. Finally, the protection based on the optimal dynamic domain-sequencing scheme, called OPT, is designed, to evaluate performance of our algorithm and to provide the good bounding for the dynamic domain-sequencing scheme with limited intra TE information. Simulation evaluation shows that the proposed scheme is effective in multi-domain path protection with more efficient resource utilization, lower blocking probabilities and less inter-domain cost. Furthermore, the performance of it is near to OPT.

Local segment-shared protection based on source egress gateway selection for multi-domain optical mesh networks

Survivability for multi-domain optical networks is becoming a key parameter due to expanding network. In order to provide the shared-path-protected lightpath in multi-domain optical mesh networks, we propose a protection solution, called GSLSSP. A new source egress gateway selecting mechanism is adopted in this solution. For each connection request, this mechanism can enable the source node to select a better egress gateway node to the destination domain and compute one inter-domain working path near the optimal path with the cooperating of this gateway node, under scalability and domain privacy constraint of multi-domain networks. And then one intra-domain link-disjoint local segment-backup path for each working-segment path is computed out in each single-domain passed by the working path. Simulation evaluation shows that the proposed scheme can provide 100% protection ability for multiple failures. Besides, it is effective in multi-domain path protection with more efficient resource utilization, lower blocking probabilities and less inter-domain cost than other schemes.

Survivability optimization and analysis of network topology based on average distance

A method is proposed to optimize the network survivability based on average distance. We explain the merit of shorter average distance and design the topologies which have minimum average distance then choose the optimal network from them by the network performance analysis under random failure.

CE Dual-homing protection in Layer 1 VPN

Layer 1 VPN (L1VPN) extends the notion of VPN to the optical domain to provide virtually dedicated circuit like leased lines, so that the security is more enhanced. Despite their secure gains from channel isolation, VPNs still suffer fragilities resulting from link-failures or node-failures. Extensive activities on survivability designs for wavelength-routed optical networks are proposed, including various protection and restoration schemes, but concerns on network edge are rare. Dual-homing is an effective skill to achieve survivability gains for L1VPNs. There are two dual-homing mode: Active/Standby mode and Load-Sharing mode In this paper, we investigate the problem of PE assignment, which is the key of dual-homing design and is NP-hard. We formulate it as an integer programming problem, and propose heuristic solutions. Simulation results show that the proposed solutions work in a correct and effective way and the Load-Sharing mode has higher bandwidth efficiency than Active/Standby mode.

A Distributed Multicast Label Switched Path Setup Scheme to Solve the Multi-destination Reservation Collision

Generalized Multi-Protocol Label Switching (GMPLS) appears as a promising candidate to implement the control plane for next-generation optical networks. In GMPLS-based wavelength division multiplexing (WDM) optical networks, existing resource reservation protocol (RSVP) may fail to setup a multicast Label Switched Path (LSP) with high probability, since multiple destinations in one multicast session may reserve different wavelengths and result in reservation collision at branch nodes. In this work, we extend the existing GMPLS RSVP signaling protocol and propose an efficient scheme to set up optical multicast LSP and avoid wavelength resources collision, called Last-hop Label Set (LLS) scheme, by introducing a new object called Last-hop Label Set object in Resv message. Once the setup of a multicast LSP fails caused by wavelength reservation collision at a branch node, the branch node can re-reserves a new wavelength according to the Last-hop Label Set object within Resv messages. The numerical results indicate that the proposed LLS scheme offers lower blocking probability compared to the existing GMPLS signaling scheme.

Group-Multicast Capable Optical Virtual Private Ring with Contention Avoidance

A ring based optical virtual private network (OVPN) employing contention sensing and avoidance is proposed to deliver multiple-to-multiple group-multicast traffic. The network architecture is presented and its operation principles as well as performance are investigated. The main contribution of this article is the presentation of an innovative group-multicast capable OVPN architecture with technologies available today.