Yiqiang Hua

Extending path computation element for lightpath restoration in wavelength-switched optical networks

Current generalized multi-protocol label switching (GMPLS) standards do not include adequate models for wavelength-switched optical networks (WSON) in recovery mechanisms. In this letter, GMPLS/path computation element (PCE) extensions are applied for the restoration of the lightpaths disrupted by collision or optical impairment. A reserved deection routing scheme is proposed to achieve fast restoration. It uses the expanded PCE component to compute and assign the backup paths for lightpath recovery. Numerical results demonstrate that this scheme is effective and low cost.

Wavelength pre-assignment collision schedule for wavelength-routed optical networks

A novel wavelength assignment scheme called the wavelength pre-assignment collision schedule (WPCS) is proposed for wavelength-routed networks. The WPCS pre-assigns the wavelength at the forward detection phase, and schedules the potential collision by priority. The potential collision is scheduled at the forward detection phase and the blocking of the wavelength assignment is reduced. Simulation is conducted with several other existing schemes. The numerical results show that WPCS performs better than other schemes in blocking probability under various traffic conditions.

Serial Recovery in PCE Enabled Wavelength Routed Optical Network

In this paper, Serial Recovery (SR) scheme is proposed in PCE enabled wavelength routed optical network. In some scenarios recovery time is not strictly emphasized and SR can be deployed. SR can experience lower blocking than traditional Parallel Recovery (PR) and SR can introduce Quality of Service (Qos) into recovery process. Simulation is conducted with SR and PR. Our numerical results show that SR performs better than traditional PR schemes in blocking probability under various traffic conditions.

Active-Fault-Alarm based Dynamic Temporary Protection Mechanism for MPLS-TP optical networks

This article proposes an Active-Fault-Alarm (AFA) based Dynamic Temporary Protection Mechanism (DTPM) that is applied into the multi-protocol label switching transport profile (MPLS-TP) optical network. The new DTPM, by using the AFA function, can establish dynamically the so called temporary protection path (TPP) for the work path in advance before possible fault occurs and keep flexibly the TPP only during the low-quality or fault period of the work path. Therefore, the novel DTPM is greatly different from the 1:1 Traditional Linear Protection Mechanism (TLPM). Experimental results show that the DTPM has better performance in terms of flexibility and efficiency.

QOS-aware lightpath scheduling mechanism for GMPLS/PCE Lambda Gird

Lambda-Gird offers dedicated, optical, circuit-switched, point-to-point connections, which may be reserved exclusively for Data-intensive applications. However, such dedicated high-speed connections push the network congestion and its transmission rate of these applications may not match the bandwidths of dedicated lightpath in most case. So in this paper, a new QoS-aware lightpath scheduling mechanism called QLSM has been proposed to extend the GMPLS/PCE for lightpath establishment and restoration in Data-intensive DWDM. The QLSM scheme assigns a wavelength-weight to denote the concurrent reservation wavelength utilization rate and then PCE could select several preferable wavelengths according to the weight for source node. It will also block the new request step by step according to QoS level when the lightpath restored. The experimental results show that QLSM based on QoS level performs better in total blocking and resource utilization rate.

Wavelength deployment in GMPLS network for data-intensive transmission

Dynamic resource distribution of General Multi-protocol Label Switch (GMPLS) network provides an appropriate technology for Data-intensive transmission. This technique can support the application of optical virtual concatenation (OVC) which uses a group of wavelengths to transmit a large scale data in parallel. With RESV-TE protocol, optical channels of OVC can be easily established in GMPLS network. A novel contention resolution for RSVP-TE protocol extension was proposed to relieve the resource contention on the process of channel establishment. It can diminish the backward blocking probability by redistributing resource to the Label Switch Path (LSP) request which is closer to source.

Single-node failure notification for data-intensive transmission in GMPLS network

As the bi-directional failure notification may cause signaling burst conflict in a short time, a mechanism named single-node failure notification (SNFN) based on RSVP-TE (Resource reSerVation Protocol -Traffic Engineering) is proposed. SNFN implemented by extending the RSVP-TE protocol rules the node issuing the notification signaling call according to ordered numbers, no matter up-stream or downstream. SNFN reduces the blocking probability and improves the restoration performance of the wavelength collision in the GMPLS-based optical network with the data-intensive connections. It can also improve the restoration rate in the cost of tolerable restoration time.