Routing in Automatically Switched Optical Networks Using Hop Routing Algorithm

Effective Routing and Wavelength Assignment are the two important criteria used for improving the blocking performance in optical Wavelength Division Multiplexing (WDM) networks. Due to the increase in data traffic in the internet scenario, the existing algorithms for effective wavelength assignment and routing are not adequate to provide an optimal level of performance. Hence, the need arises to propose efficient routing and wavelength assignment algorithms to meet the requirements of different types of networks that are part of the internet. In this paper, Hop Routing Algorithm (HRA) has been proposed to improve the Overlay Routing Algorithm (ORA) for Automatically Switched Optical Networks (ASON). The existing ORA allocates long light path for each connection request. This is not an efficient method for utilizing the light path if the connection request requires only minimum bandwidth. The proposed HRA checks the bandwidth requirement of the connection request and compares it with link bandwidth. If the bandwidth of the connection request is lower than the available link bandwidth, then HRA allocates a light path for the next hop. Thus, longer light path for each small connection request is restricted by HRA and it uses minimum number of wavelengths. It is observed that the proposed HRA accepts more requests without exceeding the available bandwidth. From the simulation studies it is found that the packet loss has been reduced in the proposed HRA. Also, this paper presents a computational model for estimating the Blocking Probability in ASON network.