Hyup Jong Kim

Back-pressure buffering scheme to improve the cell loss property on the output buffered ATM switch

We have studied back-pressure buffering mechanisms to improve the cell loss property in output buffered ATM switches. In order to minimize the cell loss in an output buffer, the back-pressure buffering mechanism pressures the transmission of input cells to the switch fabric according to the load status of the output buffer. We have studied and proposed two back-pressure buffering mechanisms; one is the push-out mechanism with a single FIFO and the other is the selective pressure mechanism with a shared memory. The main subjects of this study were: (1) a performance comparison using computer simulation between a system without back-pressure buffering and a system with the proposed back-pressure schemes and (2) a proposal for a practical implementation structure. Through the simulation results, we conclude that a pure push-out mechanism cannot improve the performance but a selective pressure mechanism will provide enormous improvement of the cell loss property with a small sized memory.

Locally embedded PSA method and architecture of signaling and call/connection control in UNI

A Proxy Signaling Agent (PSA) function is to provide signaling functionality for one or more users that do not support UNI signaling protocol. PSA can be considered in such a way as either remote or local. In the case of the remotely supported PSA method, it is unavoidable to modify, network elements in the ATM network, in order to support communications required between the PSA service provider and them). This paper proposes a locally embedded PSA method that can be applicable to ATM switches or access nodes for efficient networking. The proposed method can minimize the modification of network elements on the ATM network. In addition, we also propose architecture of signaling and call/connection control in an access node system realized with the locally embedded PSA method.