Motoo Nishihara

STM-ATM migration plan with bridge functions

The implementation of the asynchronous transfer mode (ATM) network, as one of the vehicles for B-ISDN services, has been the subject of many enthusiastic studies. ATM networks will gradually expand to meet societys needs for B-ISDN. Since connections with existing STM networks will be required in this process of expansion, it is necessary to analyze bridge functions with them. It is also imperative that the main parts of services provided through existing STM networks such as plain old telephone services (POTS) and N-ISDN basic access services (2B+D) be efficiently integrated into an ATM network. The paper classifies and compares bridge functions with STM networks while clarifying an ATM network introduction scenario. The paper then studies the function that is considered to be most important, ATM cell assembly and disassembly (CLAD) for POTS and 2B+D service signals.<<ETX>>

A cut-through transmission of IP packets and novel address resolution technique with cost-effective implementation

This paper proposes a new scheme for connectionless transmission of IP packets over an ATM network. The proposed scheme uses cut-through transfer of IP packets on a packet by packet basis. The proposed connectionless (CL) network uses VCI in the ATM header as the packet identification label. VC resources required on a given VP link is the number of IP packets that are concurrently transmitted within that VP. The proposed CL network is composed of network edge devices, called CL-GW (connectionless gateways), and core network nodes, called CL-XN (connectionless exchange nodes). They are interconnected by a semi-permanent virtual path in a partial mesh configuration. There is neither need for connection establishment prior to packet transfer nor need to provision a separate network to carry IP packets, i.e., connection-oriented ATM traffic and IP traffic can coexist within the same ATM network. Our proposed scheme is based on a concept where core network nodes should be able to transfer IP packets quickly at an ATM cell level (thus, need to eliminate packet level processing or special signaling between nodes), and process intensive functions be distributed to the network edge devices. CL-GW utilize a newly developed hardware address search engine, which can perform wire-speed search even for a 622 Mbit/s link speed. CL-GW and CL-XN are implemented as interface cards of an ATM crossconnect platform, which means that the proposed scheme can be installed cost-effectively.