Wavelength-division multiplexing (WDM) networks provide reconfigurability and the possibility of creating single hop communication channels between end nodes. This eliminates the electronic processing at intermediate nodes and reduces delay significantly.

However, because of the limited number of network interfaces and other scalability issues, single hop channels do not support all traffic demands. Some of the traffic requires routing or switching over multi-hop lightpaths to reach the destination. Such traffic is referred to as multi-hop traffic. The optimization of multi-hop traffic has significant impact on the performance of optical networks.

In this paper, we propose an integrated logical topology design and traffic-grooming algorithm for the optimization of the multi-hop traffic. This is enabled by the multi-hop lighpath setup mechanism, which is to establish lightpaths from/to intermediate nodes to/from end nodes for multi-hop traffic.

The proposed algorithm considers traffic grooming for multi-hop traffic when the logical topology is designed and always gives high priority to high traffic demands when allocating network resources. Consequently, it leads to low delay and to high network throughput. Simulations indicate that the proposed algorithm has substantial improvement in terms of the average weighted hop distance and network throughput in comparison with known algorithms such as HLDA, MMHA and MRU.