Service guarantees/congestion control in high speed networks

A method for use in performing congestion control of data elements in a data network having internal resources, each of said internal resources comprising a queue and a server, and each data element being associated with a particular channel, the method characterized by the steps of:

• making a determination that a global congestion threshold for an internal resource is exceeded, said global threshold being less than the maximum capacity of the queue of said internal resource;
• and
• in response to said determination, dropping a data element arriving at said internal resource without ever placing said data element in said queue of said internal resource when said arriving data element causes a threshold that is a predetermined function of at least a bandwidth associated with said channel to be exceeded, said dropping being independent of any indication, stored for said data element, to indicate the capability of said data network to drop said data element.

A method for controlling congestion in a network in which resources of said network serves data elements from respective queues according to a head-of-the-line weighted round-robin service discipline so that each of said queues is logically divided into a plurality of sub-queues, one sub-queue for each active channel at each resource, said method characterized by the steps of:

• receiving a new data element that requires service at a resource;
• and
• dropping said new data element without ever putting it into the queue of said resource only when both i) the length of said queue has exceeded a predetermined threshold the value of which is less than the maximum Capacity of the queue of said resource and ii) the sub-queue of the channel of said new data element has exceeded a predetermined threshold for said sub-queue of said channel, said dropping being independent of any indication, stored for said data element, that said data element exceeded a contracted-for bandwidth of the channel from which it was received.

A method for use in a data network in which data elements are communicated over respective associated channels among an interconnected plurality of network access point resources and network internal resources, said network access point resources receiving data elements from data element sources and said network internal resources receiving data elements only from said access point resources or others of said internal resources, said channels having associated bandwidth allocations, said method comprising the steps of:

• processing said data elements into said data network independent of said bandwidth allocations;
• and
• in response to the existence of a congestion condition at a particular internal resource, dropping data elements received from a particular channel or channels which, on a proportional basis with respect to their respective associated bandwidth allocations, have most exceed their bandwidth allocations over a predetermined time interval.

A method for use in controlling congestion at a resource of a data network at which resource a plurality of channels are active, said resource comprising at least a queue and a server, the method characterized by the steps of:

• making a determination as to whether or not said resource can guarantee that it will service a data element arriving on a particular active channel of said plurality of channels prior to placing said arriving data element in said queue, said determination being made as a function of i) a contracted-for bandwidth for each of said active channels, ii) the arrival rate of data elements for the particular active channel and iii) the arrival rate of data elements for each active channel of said plurality that is not said particular active channel, said determining being independent of any indication, stored for said data element, that said data element has not exceeded the contracted-for bandwidth of the channel on which it arrived;
• and
• placing said arriving data element in said queue only when the result of said determination is that said resource can guarantee that it will service a particular arriving data element.