For applications relying on the transfer of multimedia, and in particular continuous media, it is essential that quality of service (QoS) is guaranteed system-wide, including end-systems, communications systems and networks. Although researchers have addressed many isolated areas of QoS provision, little attention has so far been paid to the definition of an integrated and coherent framework that incorporates QoS interfaces, management and mechanisms across all architectural layers. To address this deficiency, we are developing a Quality of Service Architecture (QoS-A) which offers a framework to specify and implement the required performance properties of multimedia applications over high-performance ATM-based networks. The QoS-A incorporates the notions of flow, service contract and flow management. Flows characterise the production, transmission and eventual consumption of single media streams, service contracts are binding agreements between users and providers and flow management provides for the monitoring and maintenance of the contracted QoS levels. This paper provides an overview of the QoS-A and focuses particularly on the role of the transport service and protocol in the architecture. We describe a multimedia enhanced transport service (METS), flow management and transport layer service contract. We show how QoS levels contracted at the transport service interface can be assured in the context of our local ATM environment.

https://cs.dartmouth.edu/~campbell/papers/thesis.pdf

A quality of service architecture

A monitor for and a method of examining packets passing through a connection point on a computer network. Each packets conforms to one or more protocols. The method includes receiving a packet from a packet acquisition device and performing one or more parsing/extraction operations on the packet to create a parser record comprising a function of selected portions of the packet. The parsing/extraction operations depend on one or more of the protocols to which the packet conforms. The method further includes looking up a flow-entry database containing flow-entries for previously encountered conversational flows. The lookup uses the selected packet portions and determining if the packet is of an existing flow. If the packet is of an existing flow, the method classifies the packet as belonging to the found existing flow, and if the packet is of a new flow, the method stores a new flow-entry for the new flow in the flow-entry database, including identifying information for future packets to be identified with the new flow-entry. For the packet of an existing flow, the method updates the flow-entry of the existing flow. Such updating may include storing one or more statistical measures. Any stage of a flow, state is maintained, and the method performs any state processing for an identified state to further the process of identifying the flow. The method thus examines each and every packet passing through the connection point in real time until the application program associated with the conversational flow is determined.

Method and apparatus for monitoring traffic in a network

Techniques for creating policies for use in policy-based management of quality of service treatments of network data traffic flows are described. Policies are defined based on information about types of flows generated by an application and quality of service functions that are available in the network. Application information is received that defines flows generated by an application, including points where the application generates the traffic flows. QoS information is received that defines one of more quality of service treatments that the network device may apply to data processed by the network device. Based on the information, processing policies that associate the flows with the QoS treatments are determined. Mappings of the application information to the QoS treatments, which may be used to generate the quality of service value when the application program generates flows, are created and stored. Thus, the policies are informed both by application expertise and network expertise.

Method and apparatus for creating policies for policy-based management of quality of service treatments of network data traffic flows

A distributed network access system (30) in accordance with the present invention includes at least an external processor (42) and a programmable access device (40). The programmable access device has a message interface coupled to the external processor and first and second network interfaces through which packets are communicated with a network. The programmable access device includes a packet header filter and a forwarding table (50) that is utilized to route packets communicated between the first and second network interfaces. In response to receipt of a series of packets, the packet header filter in the programmable access device identifies messages in the series of messages upon which policy-based services are to be implemented and passes identified messages via the message interface to the external processor for processing. In response to receipt of a message, the external processor invokes service control on the message and may also invoke policy control (48) on the message.

Network access system including a programmable access device having distributed service control

A system and method are provided for managing a flow of packets through a network interface. A network flow is established for each datagram sent from a source entity to a destination entity. A flow key identifies the source and destination entities and is stored with information concerning validity of the flow, data sequencing within the flow datagram and how recently the flow was active. When a packet within a network flow is received, an operation code is generated for identifying whether the packet is suitable for a particular network interface function. One operation code may indicate that a packet contains data to be re-assembled with other flow data. Another operation code may indicate that a packet is unsuitable for data re-assembly. Another operation code may specify that the packet is a control packet, has no data, or was received out of order.

Method and apparatus for managing a network flow in a high performance network interface

A multi-layer network element (12) for forwarding received packets from an input port to one or more output ports (38) with quality of service. When output queues (54) exceed or meet a threshold value below the queue's capacity packets are randomly discarded. When the queue becomes full, the network element determines which flow caused the queue to overflow. The priority of that flow is lowered. In a multicast packet, the packet may have different priorities at each output port. Scheduling of multiple output queues at each output port uses a weight round robin approach that allocates a weight portion of packets to transmit at each time interval. A packet is not interrupted during its transmission, even if the weight portion is met during a packet's transmission. The excess number of bytes transmitted as a result of not interrupting the packet are accounted for in the next round.

A system and method for a quality of service in a multi-layer network element

The invention generally provides for a network element and methods in the network element for allowing a matching (305) entry in a forwarding memory (113) to be found in a single search of the memory, for determining (311) when an entry should be placed in the memory, and for determining (325) when an entry should be removed from the memory, in order to make more efficient use of the fixed space available in the memory. The invention is particularly useful in making more efficient use of a Content Addressable Memory (CAM) for storing flow entries, and configuring the CAM to index an associated memory (114) that stores forwarding and quality of service information for each CAM entry.

Management of entries in a network element forwarding memory

A peer-to-peer email system and methods are provided for distributed email distribution, prevention of SPAM, and efficient email storage. Each email client also serves as a node in the peer-to-peer system, relaying email messages and/or attachments. Large attachments may be transmitted directly from sender to receiver, and if the receiver is not online at the time the sender sends the attachment, the receiver can request the attachment from the sender at a later time.

Peer-to-peer email

As multi-media applications such as video-on-demand and video conferencing become more common, the classes of systems and networks participating in these applications are becoming more diverse. Where several endpoints need to access the same video stream simultaneously, multicast protocols are often employed to reduce the duplication of network traffic across common links. Previous literature has discussed the concept that hierarchical media encodings can be used to achieve some form of stream scalability within a multicast network. This paper discuss the networking issues associated with encoding hierarchical streams and mapping them to a multimedia transport service interface.

Network Support for Dynamically Scaled Multimedia Data Streams

Systems and methods for distributing peer-to-peer communications are provided herein. Exemplary methods may include masking identification of two or more client nodes on a communications channel of a peer-to-peer communications network by directing peer-to-peer communications of the two or more client nodes through a proxy node, the proxy node including a disinterested client node relative to the two or more client nodes, the disinterested client node providing network resources to the peer-to-peer communications network.

Don Hoffman

Papers

A system and method for a quality of service in a multi-layer network element

Management of entries in a network element forwarding memory

Peer-to-peer email

Network Support for Dynamically Scaled Multimedia Data Streams

Systems, methods and media for distributing peer-to-peer communications