Cisco Technology, Inc.

Hamesh Chawla

John Gary Waclawsky

A system and method are provided which enable a data communications device to be programmed to automatically and dynamically modify allocation of resources upon the occurrence of specific events or times without having to break active sessions of data communications. Resource allocations can be made by bandwidth reservations provided to a data communications device via a network policy or via individual bandwidth reservation messages. The bandwidth allocation information can specify a session of data communication and future bandwidth modification information, such as a time or event, that will cause the data communications device to modify an amount of bandwidth reserved for the specified session of data communications.

Apparatus and methods for providing event-based data communications device configuration

Techniques are provided for controlling a flow of packets in a data communications device. A first technique involves transferring packets of a particular packet flow based on an initial policy scheme, and planning a scheme change to change the initial policy scheme to a new policy scheme based on conditions within the data communications device existing while transferring the packets of the particular flow based on the initial policy scheme. The first technique further involves providing a change signal to the source of a particular packet flow (e.g., a sending host). The change signal indicates that the data communications device has planned the scheme change. Additionally, the first technique involves processing the scheme change based on either a reply signal from the source or an absence of a reply signal from the source. Another technique involves outputting packets of a particular packet flow to a data communications device that transfers the packets of the particular packet flow based on an initial policy scheme. Additionally, the technique involves receiving, in response to the outputted packets of the particular packet flow, a change signal from the data communications device. The change signal indicates that the data communications device has planned a scheme change to change the initial policy scheme to a new policy scheme. Furthermore, the technique involves providing, to the data communications device, a reply signal that provides direction for processing the scheme change.

Methods and apparatus for managing a flow of packets using change and reply signals

A data communications device has a controller which includes means for intercepting a request signal transmitted from a source to a host computer having a host destination address. The request signal includes the host destination address. The request signal is originally destined for receipt by a host computer that would respond with control information for controlling a manner in which the source transfers a data stream. The controller further includes means for originating a control signal in response to receiving the request signal. The control signal includes the control information for controlling the manner in which the source transfers the data stream. The controller further includes means for providing the control signal to the source to individually control the manner in which the source transfers the data stream among multiple data streams transferred by the source. The source is a routing mechanism operating within the data communications device.

Methods and apparatus for controlling a data stream using a host agent acting on behalf of a host computer

Techniques are provided for controlling a data stream without communicating with a host generating the data stream. A host agent (associated with the host generating the data stream) runs in a computerized data processing device and receives a request signal from a request signal source (e.g., a router seeking direction on how to handle the data stream). In response to the request signal, the host agent generates a control signal which includes the control information for controlling the manner in which the request signal source transfers the data stream.

A system capable of dynamically reserving bandwidth and adjusting bandwidth reservations for active sessions of data communication in a data communications device is provided. The system generally separates the operation of bandwidth allocation and adjustment from the operation of data transport through the device, thereby allowing bandwidth reservations and adjustments to be made without disturbing sessions of data communication that are actively being transported through the device. The system can accept requests to allocate or reserve bandwidth in a data communications device using bandwidth reservation protocols such as RSVP. The reservation requests create sender state data that can be used to compute resource allocation data. The resource allocation data can be used to label data storage locations in a data storage mechanism according to the required bandwidth reservations. A data scheduling apparatus, which is ignorant of particular sessions and specific amounts of reserved bandwidth, examines data and deposits data into data storage locations having a label corresponding to a session identification specified in the data, if any. If an unknown or no session identification is specified in the data, the data scheduler deposits data into a data storage location that is unlabeled or that has an unreserved label. Thus session bandwidth is determined by the percentage of labeled data storage locations for the session. Changes in bandwidth reservations are reflected in the separate operation of alterations made in the data storage labeling scheme, and do not affect the data scheduler, or data dequeuing mechanisms, thus allowing data sessions to continue without interruption during bandwidth adjustments.

Apparatus and methods for dynamic bandwidth allocation

A system and method are provided which enable a data communications device to be programmed to automatically and dynamically modify allocation of resources upon the occurrence of specific events or times without have to break active sessions of data communications. Resource allocations can be made by bandwidth reservations provided to a data communications device via a network policy or via individual bandwidth reservation messages. The bandwidth allocation information can specify a session of data communication and future bandwidth modification information, such as a time or event, that will cause the data communications device to modify an amount of bandwidth reserved for the specified session of data communications. In operation, a data communications device receives bandwidth allocation information indicating future bandwidth allocation modification information associated with a session of data communication. The data communications device then can determine a future event upon the occurrence of which the data communications device will modify an amount of bandwidth allocated to the session of data communication. The future event can be determined based upon the future bandwidth allocation modification information and event information such as a time signal from a clock or another event signal. The data communications device can detect the occurrence of the future event in the data communications device and in response to detecting its occurrence, can modify the amount of bandwidth allocated to the session of data communications in the data communications device. Extensions to a bandwidth reservation protocol such as the RSVP protocol are defined which allow RSVP bandwidth reservation messages to specify the future bandwidth modification information. The systems and methods of the invention may be implemented in hardware, software or a combination thereof within a data communications device such as a router, switch, hub or other network device that handles the transfer of data.

Techniques are provided for controlling a flow of packets in a data communications device. A first technique involves transferring packets of a particular packet flow based on an initial policy scheme, and planning a scheme change to change the initial policy scheme to a new policy scheme based on conditions within the data communications device existing while transferring the packets of the particular flow based on the initial policy scheme. The first technique further involves providing a change signal to the source of a particular packet flow (e.g., a sending host). The change signal indicates that the data communications device has planned the scheme change. Additionally, the first technique involves processing the scheme change based on either a reply signal from, the source or an absence of a reply signal from the source.

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San Leandro, CA, United States of America

Hamesh Chawla