A system for controlling the flow of data cells through a packet switch combines both input and output buffers in a feedback loop. The fullness level of output buffers is continuously monitored and reported to an access device on the input side of the switch. The access device includes input buffers and a throttling device to stop the flow of data cells, and hold them in the input buffers, when the fullness level of the output buffers exceeds a predetermined level. A status message of output buffers fullness is compared to an access message indicating which output buffers are addressed by cells in the input buffers, and only those cells addressed to overfull output buffers are stopped by the throttling device.

Flow control system for packet switches

A fibre channel backplane configuration is capable of modular expansion, e.g., from 64 ports to 128 ports or 256 ports by a simple operation. The backplane includes connectors that provide permanent and jumper/vertical connections to support 64 users port switch in a single chassis. For a 128 port switch, two 64 port chassis are used. In the 128 port configuration, the connectors are configured to provide permanent and jumper/vertical connections to make intra-chassis and inter-chassis connections between the fabric switch and fabric input/output boards. Using jumper plugs, the jumper connectors provide vertical connections between the fibre input/output boards and fibre switch boards of two chassis. For a 256 port switch configuration, four 64 port chassis assemblies are used. The connectors are configured to provide each switch with permanent, vertical, horizontal, and diagonal connections to the fibre input/output boards of each of the four chassis.

Fibre channel switch

Asynchronous transfer mode (ATM) technology is discussed in relation to the requirements of corporate networking. An introduction to ATM switch architecture is presented. The various approaches to ATM switch design that have appeared in previously published literature are reviewed. A discussion is presented of some current issues facing the development of the ATM networks. It is argued that much simpler solutions to many of these issues may be adopted in the context of the corporate network than is permissible for the public broadband network. >

ATM technology for corporate networks

A method and apparatus for imparting fault tolerance in a switch or the like, particularly in a fibre channel director switch employed in connection with storage area network.

Method and apparatus for imparting fault tolerance in a switch or the like

ATM will provide flexibility in bandwidth allocation and will allow a network to carry heterogeneous services ranging from narrowband to wideband services. The challenge is to build fast packet switches able to match the high speeds of the input links and the high performance requirements imposed. The CCITT has standardized the asynchronous transfer mode (ATM) as the multiplexing and switching principle for the broadband integrated services digital network (B-ISDN). ATM is a packet and connection-oriented transfer mode based on statistical time division multiplexing techniques. The information flow is organized in fixed-size packets called cells, consisting of a user information field (48 octets) and a header (5 octets). The primary use of the header tag is to identify cells belonging to the same virtual channel and to make routing possible. Cell sequence on a virtual channel is preserved, a very low cell loss probability must be guaranteed ( >

ATM shared-memory switching architectures

The architecture of an asynchronous transfer mode (ATM) switching system for prototype applications is presented. The general concept to upgrade the existing ISDN switch with an ATM module is introduced, and the building blocks of this ATM module are described in detail. Switching of ATM cells is performed in a single application-specific integrated circuit (ASIC). ASICs can be cascaded to form large switching modules. Peripheral modules interface the ATM switch to external transmission systems and perform all ATM-related functions, including means for redundancy of the switching network. The redundancy scheme tolerates single failures without affecting the user information. A switching network architecture is shown to be capable of fulfilling varying demands in terms of the number of ports for ATM switches and cross connects, concentrators, and multiplexers. >

E.-H. Goeldner

Papers

A scalable ATM switching system architecture