Startup management system and method for rate-based flow and congestion control within a network

• US 6,839,768 B2
• Filed: 12/22/2000
• Issued: 01/04/2005
• Est. Priority Date: 06/13/1997
• Status: Expired due to Fees

• Current Assignee: AT&T Intellectual Property I LP (AT&T, Inc.)
• Original Assignee: AT&T Corporation (AT&T, Inc.)
• Inventors: Ma, Qingming, Ramakrishnan, Kadangode K.
• Primary Examiner(s): Jaroenchonwanit, Bunjob
• Assistant Examiner(s): Vaughn, Jr., William C.
• Application Number:
  US09/742,013
• Publication Number:
  US 20010000813A1
• Time in Patent Office: 1,474 Days
• Field of Search: 709/223, 709/224, 709/226, 709/233, 709/234, 709/235, 709/232, 709/238, 709/225, 370/229, 370/232, 370/233, 370/234, 370/235
• US Class Current: 709/235
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/263 Rate modification at the source after receiving feedback
• CPC Class Codes: H04L 47/283 in response to processing delays, e.g. caused by jitter or round trip time [RTT]
• CPC Class Codes: H04L 47/37 Slow start
• CPC Class Codes: Y02D 30/50 in wire-line communication networks, e.g. low power modes or reduced link rate

Abstract

A startup management system and method, particularly adapted for use in computer and other communication networks, is presented. Rate-based flow and congestion control mechanisms have been considered desirable, including to deal with the needs of emerging multimedia applications. Explicit rate control mechanisms achieve low loss because of a smooth flow of data from sources, while adjusting source rates through feedback. However, large feedback delays, presence of higher priority traffic and varying network conditions make it difficult to ensure feasibility (i.e., the aggregate arrival rate is below the bottleneck resource'"'"'s capacity) while also maintaining very high resource utilization. The invention applies entry and early warning techniques which increase the initial connect rate of newly connecting sources.

Claims

1. A start up management system for managing the startup of a source making a resource request through a communication link to a network, comprising:

a network monitoring unit, for monitoring the available resources of the communication link;

a source rate adjustment unit, for adjusting a currently allowed rate (ACR) at which the source would begin to transmit over the communication link before the source queues data for transmission according to an allocative function of the available resources of the link, said allocative function being determined based on a connection setup message transmitted from the source to the network over the communication link, wherein the source rate adjustment unit adjusts the currently allowed rate (ACR) when the connection setup message returns to the source from the network according to;

if (ACR <

=ER)

ACR<

−

max(min (ER, DEMAND), MCR)

else

ACR<

−

max(min(ACR+(RIF*PCR), ER), MCR),

where ER is an explicit rate defined as the lowest allocated rate associated with a switch along the communication link from the source to the network, DEMAND is a desired outgoing link rate associated with the source, MCR is a minimum rate required by the source, RIF is a predetermined rate increase factor, and PCR is a peak cell rate for the communication link, where ACR always remains above MCR; and

,

a queue draining unit, wherein the queue draining unit reduces an allocated capacity according to a solution of a function for rate reduction R, defined as follows;

R=a(x−

S)²+b(x−

S)+c, wherein S is a set-point for the queue, and x is an instantaneous queue size at the link; and

a, b and c are parameters to be solved using three points corresponding to (x,R)={(S,0), (2S, M/4), 3S,M)}, M being defined as the maximum value allowed for the rate reduction R.