1. QoS-specified Traffic Grooming Algorithm in WDM Mesh Networks Bing Xiang, Hongfang Yu, Sheng Wang, Lemin Li Communications, Circuits and Systems, 2004. ICCCAS 2004. 2004 International Conference on Volume 1, 27-29 June 2004 Page(s):633 - 637 Vol.1

2. Abstract In WDM network, the bandwidth request of a traffic stream is usually much lower than the capacity of a wavelength. Traffic grooming can aggregate low-rate connections into high-capacity lightpaths to make efficient use of the bandwidth. Authors propose a QoS-specified traffic grooming algorithm named BMST considering both the hops of lightpath and load balance in the network.

3. Introduction(1/5) A WDM network consists of WDM switches (OXCs) connected by fiber optical links. In each link, multiple wavelengths are available. OXCs enable space-switching of wavelengths from one port to another and help in establishuig circuit- switched connections called lightpaths between the nodes. This enables optical passthrough at the WDM layer and eliminates the need to electronically process all the traffic at the node

4. Introduction(2/5) Usually we can setup lightpaths using designate RWA in WDM networks,but for the RWA, there exist an assumption that every connection required a full wavelength. The network may be required to support traffic connections at rates that are much lower than the full wavelength capacity. For networks of practical size, the number of available wavelengths is still lower than the number of source to destination connections that need to be made.

5. Introduction(3/5) Traffic grooming can aggregate low-rate connections onto high- capacity lightpaths to make efficient use of the wavelength capacity. Most of the researches related to traffic grooming focused on WDM/SONET ring networks while fewer studies of traffic grooming in WDM mesh network such as [12] are presented to maximize the network throughput. The basic idea in Literature [12] can be described as follow: set up the single-hop lightpaths as much as possible subject to the network resources. use the single hop work lightpaths to construct virtual topology. low-rate connections can be groomed in the virtual topology accordingly.

6. Introduction(4/5) In the studies list above, no consideration has addressed on QoS based traffic grooming. The QoS-specified RWA algorithms proposed in [13] only suggest to setup three kinds of lightpath to support different QoS levels, those are Dedicated lightpath, Shared lightpath 'and Multi-hop lightpath respectively, But the traffic grooming is not considered. Since the load distribution of network can exercise great influence on the average transmission delay of traffic, load balance of network traffic can improve network performance efficiently.

7. Introduction(5/5) In this paper authors propose a QoS-specified traffic grooming algorithm named BMST, Balanced Maximizing Single-Hop Traffic grooming Algorithm, considering both the hop of lightpath and load balance in WDM mesh networks.

8. References [12] K.Y. Zhu, B. Mukherjee, “ Traffic Grooming in an Optical WDM Mesh Network ”, IEEE J. Select. Areas Co ’ mm., Vol. 20, N. 1, pp122-133, January 2002. [13] Y. Qin, K. Sivalingam, B. Li, “ QoS for Virtual Private Networks over Optical WDM Networks ”, SPIE/ACM/IEEE Opticomm conference at Dallas, TX, October 2000.