ATM local area network switch with dual queues

US5732087A · kind A · utility

Assignee

• Mitsubishi Electric Information Technology Center America, Inc. (ITA) · US

Inventors

• Hugh C. Lauer · Concord, US
• Abhijit Ghosh · San Francisco, US
• John H. Howard · Cambridge, US
• Harufusa Kondoh · Itami, JP
• Randy B. Osborne · Newton, US
• Chia Shen · Pelham, US
• Qin Zheng · Boxboro, US

Key dates

• Filing date: May 10, 1996
• Grant date: Mar 24, 1998
• Expiry date: May 10, 2016

Classification

• Technology area (CPC H): Electricity
• CPC primary: H04L2012/5681
• WIPO field: Digital communication
• WIPO sector: Electrical engineering

Abstract

A switch for digital communication networks includes a queuing system cape of implementing a broad class of scheduling algorithms for many different applications and purposes, with the queuing system including both a tag-based primary queue which contain ATM cells organized by priority and a secondary queue which contains ATM cells which are not yet scheduled for transmission and which are organized by virtual channel. A queuing decision module is provided to determine in which queue an incoming ATM cell should be deposited. A requeuing module operates when an event occurs that unblocks a particular virtual channel. The requeuing module, on occurrence of such an event, accesses the secondary queue to obtain another cell, to assign it priority and to move it to the primary queue. The queuing decision module, along with a virtual channel table, can be used easily to block virtual channels when necessary. The combination of queues also allows for round robin scheduling.