Microsoft Technology Licensing, LLC

Microsfot Corporation

Micdrosoft Corporation

Yoram Bernet

John R Douceur

Ofer Bar

Timothy C Kwok

Timothy Mark Moore

William J Bolosky

Shreedhar Madhavapeddi

Eric Lynn Eilebrecht

John S Holmes

Rajesh Sundaram

Tsung-Yuan Charles Tai

Arun Ayyagari

Steven P Levi

Mark Daniel VanAntwerp

Rajendra S Yavatkar

James C Stewart

Ramesh B Pabbati

Carol Ann Bell

A handle administration system is described in which software agents receive handles to various resources that they can use to obtain the resources. The described embodiments provide multiple states that can be assumed by the handles. An unassigned state is provided in which handles are not assigned to a particular resource, nor can they be dereferenced to obtain pointers to any resources. An assigned state is provided in which handles are assigned to a particular resource and can be dereferenced to obtain a pointer to the resource. A suspended state is provided in which the handles are assigned to a particular resource but cannot be dereferenced to obtain a pointer to that resource.

Suspension and reinstatement of reference handles

A system and method that enables network quality of service to be based on qualitative factors. RSVP signaling is extended to allow RSVP messages to be identified as qualitative, and to pass qualitative information with the messages. RSVP-aware network devices such as routers in the message path analyze the qualitative information and apply policy based thereon to perform admission control and allocation of resources based on qualitative factors. An application identifier is provided, along with a sub-application identifier that provides fine-grained qualitative information, such as to identify what type of network service an application is requesting. Qualitative signaling may employ RSVP integrated with differentiated services by returning a DCLASS object in an RSVP message, to assign an application's traffic to one or more aggregate classes based on a policy evaluation, which may use qualitative factors against policy for each request. For admitted requests, the application's host machine or an upstream sender may mark the packets with the appropriate aggregate classification information, whereby packets are then prioritized accordingly in the network.

Network quality of service for qualitative applications

A handle administration system is described in which software agents receive handles to various resources that they can use to obtain the resources. The described embodiments provide multiple states that can be assumed by the handles. An unassigned state is provided in which handles are not assigned to a particular resource, nor can they be dereferenced to obtain pointers to any resources. An assigned state is provided in which handles are assigned to a particular resource and can be dereferenced to obtain a pointer to the resource. A suspended state is provided in which the handles are assigned to a particular resource but cannot be dereferenced to obtain a pointer to that resource. Advantageously, a suspended handle can be reinstated to assume the assigned state. In one embodiment, the handle system is implemented by incorporating a suitable field in a handle database that is used to indicate that a handle is suspended. In another embodiment, no additional fields are necessary. Rather, handle values in the handle database are manipulated to indicate that a handle has been suspended. These manipulations can be easily undone to reinstate a handle. In the described embodiment, a three state handle system can be advantageously employed to implement a two-phase commit operation.

Suspension and reinstatement of reference

A high-resolution, per-packet measurement tool for analyzing a computer network that operates by sending a predetermined number of packets from a sender machine to a receiver machine with measurement information inserted into the packet. The system kernel at the sending machine stamps a sequence number and the sender's local time into the data section of each packet. When packets arrive at the receiver machine, they are similarly stamped by the receiving machine's kernel with the receiving machine's local time. The maintained packet information serves as the basis for latency analysis. For example, one set of latencies can be obtained with QoS mechanisms turned on, and another set with QoS mechanisms turned off, whereby the benefits of the QoS mechanisms can be accurately determined. To analyze the latencies, the present invention normalizes each time and each latency into relative latency information. Clock skew and timer jumps may be handled as part of the normalization.

Method and system for accurately calculating latency variation on an end-to-end path in a network

A traffic control application programming interface for abstracting the use of traffic control components to client applications to provide quality of service. The traffic control interface accepts input from a client application and based on that input, communicates with the operating system to control kernel level traffic control components. The client can register with the traffic control interface, and it can open and close interfaces, add, modify, and delete flows on those interfaces, and attach or delete filters on the flows. The client can also obtain data on any currently active interface, flow, or filter. The traffic control interface will send the appropriate message to the operating system, directing that the necessary tasks be performed by either a packet scheduler or a packet classifier. Those kernel level components then return through the operating system the results of the operations requested, and that return data will be passed back to the client application.

Method and system of a traffic control application programming interface for abstracting the use of kernel-level traffic control components

The invention provides Quality of Service assurances in a manner expected in other media to communications over paths that include one or more wireless links. The invention combines a subnet bandwidth manager ('SBM') at an access point ('AP') to track allocations of wireless bandwidth. The invention further incorporates multiple priority levels for packet transmission in a two-prong stochastic scheme. The first prong reserves bandwidth at each of the intermediate nodes in a transmission path subject to a veto by any intermediate node. The second prong modulates the transmission probability of a packet based on the previous failed attempts at transmission and the priority level of the packet. The overall result of this hybrid scheme is to not shut out users with the lowest priority, e.g., &#x201c;best effort&#x201d; priority, while assuring adequate bandwidth to higher priority applications.

Quality of service over paths having a wireless-link

Method and system of an application program interface for abstracting network traffic control components to application programs

The present described embodiments are embodied in a system and method for generating and validating reference handles for consumers requiring access to resources in a computer system. The system of the present described embodiments includes a resource manager having a handle administrator, a plurality of consumers, and a plurality of resources. The handle administrator includes an assignment routine, a release routine, and a dereference routine. The assignment routine issues new handles, the release routine releases handles that are no longer required (thus rendering the handle invalid), and the dereference routine dereferences handles into a pointer to a resource, which entails verifying that the handle is valid. Also included is an auxiliary sub-routine for managing used and unused records, an expansion sub-routine for efficiently expanding the handle database, a handle recycling sub-routine for recycling handles, a contraction sub-routine for efficiently contracting the handle database, a hysteresis sub-routine for probabilistically contracting the handle database, and a memory allocation failure sub-routine to improve functionality in the event of memory allocation failure. Further, the systems and methods include routines that enable a handle value to be reserved for an indication of a lack of a valid handle. The reserved handle value is never issued to a consumer for use in accessing a resource.

Generation, validation and reservation of reference handles

Described herein is an ATM cable network having a plurality of ATM subscriber interface units or set-top boxes (STBs) in individual neighborhood homes. A coax distribution plant provides a plurality of communication channels between the STBs and a neighborhood node. A cable headend serves the neighborhood node and its associated STBs through a fiber-optic trunk providing a plurality of different communication channels or frequencies. The headend includes an ATM node switch having switch ports associated with each of the different communication channels. A resource manager at the headend assigns individual STBs to respective communications channels. STBs share both upstream and downstream communications channels and switch ports. In an extended autoregistration procedure, the ATM node switch is configured to assign exclusive ranges of VPI/VCI values to the individual STBs tuned to the single switch port. During ATM cell transfer, an ATM cell originating from or destined to a specific STB uses a VPI/VCI value within the range of routing indicators assigned to the STB. This allows the headend to determine the source of all upstream data cells and allows STBs to disregard any cells not intended for them.

Dynamic ATM connection management in a hybrid fiber-coax cable network

A method and computer program product for scheduling network communication packets in a multimedia environment where different packet streams have reservations of network bandwidth to form packet flows. The present invention divides the packet scheduling function into distinct components that may be implemented as separate drivers in a layered driver environment as exists, for example, in the Microsoft Windows NT operating system. One component is called a conformer and will generate and assign to each packet in the packet flow at least one conformance time that signifies the earliest a packet may be sent and still conform to the network resource requirements associated with the flow. Many different conformance algorithms can be supported so that the best algorithm is used for a particular packet flow and the service requirements that it represents. Should it be necessary to actually hold a packet until the conformance time is met, a shaper component is used to delay the packets. Finally, a sequencer component will send packets out as fast as possible over the network interface card. Each flow of packets processed by the sequencer component has at least two priorities, one for when the packets are conforming and one for when the packets are non-conforming. The sequencer component maintains priority lists of packet flow queues and will service the highest priority queue list followed by each successive priority list until no packets remain for transmission or the network interface card is unable to handle more packets. Each priority list will have a queue discipline associated therewith that will determine in what order the packets are taken off of the respective flow queues.

Method and computer program product for scheduling network communication packets originating from different flows having unique service requirements

A method and computer program product for classifying data being processed by drivers included in a stack. The computer program product is a centralized packet classifier that receives classification requests from drivers or other clients according to a defined interface. This reduces the cost for producing a driver since less code is required initially at development time as well as a corresponding reduction in maintenance costs. The present invention groups drivers or other clients that utilize a certain body of classification information into classification families. Further, reference patterns used to make classifications are stored in separate databases depending on whether they are specific or general. There exists a single specific pattern database for all specific reference patterns regardless of classification family having a constant search time and a general pattern database for each general reference pattern for each classification family defined to the system whose search time may vary according to the amount of information contained therein. When servicing a classification request, the packet classifier will first search the specific pattern database followed by a search in the appropriate general pattern database if necessary.

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Seattle, WA, United States of America

Yoram Bernet