Patent ID: 8169906
Filing Date: 2012-05-01
Classification: H04L

Abstract:
1. A method for managing asynchronous transfer mode (ATM) traffic in a plurality of ATM flows, the method comprising: determining whether a plurality of realtime ATM flows of the plurality of ATM flows has excess bandwidth and whether a plurality of non-realtime ATM flows of the plurality of ATM flows has excess bandwidth, wherein each of the plurality of ATM flows has an ATM cell flow rate, a minimum ATM bandwidth guarantee, and a maximum ATM bandwidth limit, wherein transmission of ATM cells in each ATM flow is based on a transmit fraction of the ATM flow such that an ATM cell is transmitted in each ATM flow only when the transmit fraction of the ATM flow is greater than or equal to a generated random number, the transmit fraction being between zero and one, wherein determining whether any of the plurality of ATM flows has excess bandwidth comprises determining whether any of the plurality of ATM flows has excess bandwidth in a current refresh period, providing an excess bandwidth signal for the current refresh period, the excess bandwidth signal being one when excess bandwidth exists and zero when excess bandwidth is not available, and providing an average excess bandwidth signal for the current refresh period, the average excess bandwidth signal being an exponentially weighted moving average of the excess bandwidth signal; responsive to one or more of the plurality of ATM flows having excess bandwidth, gradually increasing the ATM cell flow rate of a first ATM flow having excessive bandwidth without exceeding the maximum ATM bandwidth limit of the first ATM flow having excess bandwidth, and, provided a threshold number of ATM cells are present in a second ATM flow having excessive bandwidth, without falling below the minimum ATM bandwidth guarantee of the second ATM flow having excess bandwidth, wherein gradually increasing the ATM cell flow rate of each ATM flow having excess bandwidth comprises linearly increasing the transmit fraction of each ATM flow having excess bandwidth towards one, wherein linearly increasing the transmit fraction of each ATM flow having excess bandwidth comprises selecting a constant for each ATM flow having excess bandwidth, calculating a product for each ATM flow having excess bandwidth by multiplying the constant selected for the ATM flow by the average excess bandwidth signal, and calculating a transmit fraction of each ATM flow having excess bandwidth for the current refresh period by adding the product calculated for the ATM flow to a transmit fraction of the ATM flow for a previous refresh period; providing the plurality of realtime ATM flows to a first queue and providing the plurality of non-realtime ATM flows to a second queue; and outputting, by a scheduler, the plurality of non-realtime ATM flows from the second queue based upon a threshold number of ATM cells present in the first queue and the minimum ATM bandwidth guarantee for the plurality of non-realtime ATM flows.