Transwitch Corporation

Fujitsu Corporation

William Lipp

Daniel C Upp

Subhash Chandra Roy

Michael M Renault

Santanu Das

Jitender K Vij

Satoshi Kakuma

Steven Benoit

Frederick R Carter

Rajen S Ramchandani

H Paul Holzworth

Gary Deval

An adjustable connection admission control method and device for packet-based switches assigns equivalent bandwidths to variable speed connections. The equivalent bandwidths of the variable speed connections are increased or reduced by a scaling factor to achieve an assigned bandwidth. The method and device determine whether to accept or refuse new variable speed connections based on whether the sum of equivalent bandwidths for existing variable speed connections and new variable speed connections exceeds the bandwidth available to variable speed connections. The connection admission control method and device also determines whether to accept or refuse new constant speed and new unspecified connections. For constant speed connections, the sum of existing and new constant speed connections is obtained. If the sum of bandwidths for existing and new constant speed connections exceeds a maximum factor, the bandwidth available to constant speed connections is reduced by a constant speed traffic factor. At least a portion of the unspecified connections do not have a sustained cell rate. The sustained cell rate is determined by multiplying a peak cell rate by an SCR factor. Equivalent bandwidths are assigned to unspecified connections and are increased or reduced by the scaling factor to achieve an assigned bandwidth. New unspecified connections are accepted or refused based on whether the sum of bandwidths for existing and new unspecified connections exceeds a bandwidth available to unspecified connections. The scaling factor, traffic factor, maximum factor, constant speed traffic factor and SCR factor can be adjusted.

Adjustable connection admission control method and device for packet-based switch

A network switch includes at least one port processor and at least one switch element. The port processor has an SONET OC-x interface (for TDM traffic), a UTOPIA interface (for ATM and packet traffic), and an interface to the switch element. In one embodiment, the port processor has a total I/O bandwidth equivalent to an OC-48, and the switch element has 12&times;12 ports for a total bandwidth of 30 Gbps. A typical switch includes multiple port processors and switch elements. A data frame of 9 rows by 1700 slots is used to transport ATM, TDM, and Packet data from a port processor through one or more switch elements to the same or another port processor. Each frame is transmitted in 125 microseconds; each row in 13.89 microseconds. Each slot includes a 4-bit tag plus a 4-byte payload. The slot bandwidth is 2.592 Mbps which is large enough to carry an E-1 signal with overhead. The 4-bit tag is a cross connect pointer which is setup when a TDM connection is provisioned. The last twenty slots of the frame are reserved for link overhead. Thus, the frame is capable of carrying the equivalent of 1,680 E-1 TDM signals. For ATM and packet data, a PDU (protocol data unit) of 16 slots is defined for a 64-byte payload. The PDUs are self-routed through the switch with a 28-bit routing tag which allows routing through seven switch stages using 4-bits per stage. Bandwidth is arbitrated among ATM and Packet connections while maintaining TDM timing.

Network switch which supports TDM, ATM, and variable length packet traffic and includes automatic fault/congestion correction

Method for switching ATM, TDM, and packet data through a single communications switch

Method and apparatus for switching ATM, TDM, and packet data through a single communications switch while maintaining TDM timing

Growing community of inventors

New Haven, CT, United States of America

William Lipp