TOSHIBA ANNOUNCES FIRST UNI 4.0 COMPLIANT 155Mbps SAR FOR ATM SERVER AND SWITCH APPLICATIONS; Toshiba offers ATM NIC designers a cost-effective solution supporting multimedia applications and ATM Forum-Compliant Available Bit Rate Service

Business Wire, Sept 9, 1996

SAN JOSE, Calif.--(BUSINESS WIRE)--Sept. 9, 1996--Toshiba America Electronic Components Inc. (TAEC) today announced the first single-chip 155 Megabits per second (Mbps) segmentation and reassembly (SAR) chip with hardware implemented, ATM Forum-compliant Available Bit Rate (ABR) service, which provides rate-based traffic management control. The new device, called the Meteor (part number TC35856F), provides MPEG support for multimedia applications and provides end-to-end connections with a high quality of service. It is targeted for high-speed, high-bandwidth servers and switches connecting legacy LANs to the ATM backbone.

"Meteor is the first jointly developed product resulting from the Toshiba/Digital partnership, announced last September, to develop highly optimized ATM SAR products for the hub/switch and adapter card markets," said Ravi Sethi, director of TAEC's networking business unit. "The technology-exchange alliance has allowed us to bring industry-leading high performance ATM solutions to market earlier. Meteor is fully compliant with the latest ATM specifications for UNI 4.0, which means that it is the first to support Constant Bit Rate (CBR), Available Bit Rate (ABR) and Unspecified Bit Rate (UBR) service classes. It also contains some unique features, such as MPEG2 packet transmission support and a credit-based flow control option that provides extra reliability on an ATM network by minimizing cell loss."

"Our relationship with Toshiba enables Digital to respond to our customers' requirements for leading ATM products that are compliant with the latest industry standards and provide exceptional price/performance," said Peter B. Dunbeck, director of backbone networks at Digital Equipment Corporation's Network Product Business. "Meteor, as the first SAR with ATM Forum-compliant ABR in hardware, enables the rapid introduction of this long-awaited feature before other vendors."

The new SAR supports MPEG transport cells, allowing designers to include features that will support multimedia applications in their systems. Meteor also uses host memory-based frame segmentation and reassembly, which leads to savings in local memory costs.

With the addition of this device, Toshiba provides a complete Asynchronous Transfer Mode (ATM) solution for Network Interface Cards (NICs) targeted for servers. The new SAR is designed to work with new standards-compatible 155Mbps SONET framer chips from Toshiba, and the company's optical transceivers.

"The first in a family of 155Mbps SAR devices, Meteor's architecture is designed to efficiently scale from low-cost desktop applications to high-end servers. The current device will support up to 1,024 virtual channels (VCs) for high-end servers and switches, and support for 4,096 VCs will be available by the end of this year. Future generations also will feature the same high-performance SAR capability, and will be optimized for specific applications such as server NICs, client NICs and switches," Sethi said.

The TC35856F supports the PCI bus and the Universal Test and Operations Physical layer Interface for ATM (UTOPIA). The device interfaces to the 33MHz, 32-bit PCI bus following the PCI Local Bus Specification, Revision 2.1, to provide high performance, low latency data transmission. Its PHY interface implements the standard UTOPIA Level II interface specification of an 8-bit interface running at 33MHz. The chip also supports a reversible UTOPIA mode of operation, allowing the device to be connected to the switch fabric through the same mechanism as all other ports in the switch.

Meteor contains a DMA engine that sends the protocol data units (PDUs) to and from the host memory for segmentation and reassembly. This design eliminates the necessity for large amounts of memory on the adapter. For example, the device requires only 128 kilobytes (KB) of on-board, 15 nanoseconds SRAM to support 1,024 transmit and receive VCs simultaneously, and 64KB SRAM to support 256 VCs.

Meteor supports segmentation and transmission of up to 1,024 AAL5 PDUs simultaneously with AAL5 Cyclic Redundancy Check (CRC) generation. The IC segments AAL5 PDUs, appends the cell headers to each ATM cell created by the segmentation process, computes AAL5 CRCs, and writes the computed CRCs in the transmitted PDUs. It can reassemble 1,024 AAL5 PDUs simultaneously in the receive direction and verifies the AAL5 CRC.

Meteor provides full performance at Synchronous Transport Signal Line 3 (STS-3c) line rates (155 Mbps). It provides full support for the ATM Forum UNI 4.0 traffic management specifications, including CBR, ABR and UBR. Meteor generates and processes ABR RM cells and provides per-VC rate control without host-driver intervention. Support for other classes of service is provided via raw 52-byte cells. In addition to the end-to-end flow control provided by the ABR service class, the device provides full Generic Flow Control support to maintain transmit bandwidth guarantees for uncontrolled VCs. Digital's FLOWmaster(tm) flow control is also supported as an option to provide zero cell loss, best-effort quality of service with increased reliability.