Various approaches on optical network systems using wavelength-division multiplexing (WDM) technique have been proposed. It is difficult to make a scale of WDM network larger since a number of the optical wavelength which can be used is limited. In order to make easily larger scale of network, multi-hop WDM network have been proposed. We have studied 2-hop network: RookNet which has simple routing algorithm and high network throughput. Nodes in RookNet are divided into row groups and column groups and are placed in a mesh form. Packets are transferred between nodes over 1-hop or 2-hops. The 2-hop transfer means that a source node sends packets to a destination node via a relay node. When 2-hop traffic increases, relay processing time in a relay node is increasing. This is the reason that network throughput becomes low. To solve this problem is very important. In this paper, we show RookNet rearrangement algorithm which replaces location of node within group so as to decrease the 2-hop traffic and to maintain high network throughput. Proposed rearrangement algorithm can achieve improvement of 10 percent in terms of throughput. We also propose RookNet configuration which discriminates optical wavelength and subcarrier effectively in order to decrease the relay processing time.

Recently as one of attractive applications in the B-ISDN era, LAN/MAN interconnection through an ATM network has been coming up because burstiness of LAN/MAN data traffic is applicable to distinctive features of cell based ATM network. In order to overcome a difference of the connection mode, i.e., CL packet transfer of LAN/MAN and CO cell transfer of ATM network, a number of interworking and bandwidth allocation mechanisms have been proposed. These methods, however, indicate both merits and drawbacks concerning with CL data transfer quality, network resource efficiency and processing overhead in IWU/CLS and the network, and have been mostly evaluated only for a single IWU model. This paper aims at showing the most appropriate method of LAN/MAN interworking for IWU-IWU or IWU-CLSF connection. In the paper, some interworking issues including a general qualitative assessment are clarified. We then evaluate the selected five interworking methods based on Bandwidth Renegotiation (BR) and VC Establishment (VCE), which are combined with Traffic Enforcement Functions (TEFs) based on policing mechanisms and Cell Loss Control (CLC) scheme. By transient and stationary simulation approach for a single IWU and an IWU-CLS connection model, the most applicable method is indicated as a case study from view points of the communication quality, effective use of the bandwidth and processing load.