3com Corporation

Juniper Networks, Inc.

William D Townsend

John A Flanders

David C Ready

Leonard Schwartz

Ryan T Ross

Thomas A Lemaire

Thomas V Radogna

Brian W Bailey

James Scott Hiscock

David Lipschutz

Sanjay Wadhwa

Joris Johannes Maria Wils

John Liddy

Stephen L Van Seters

Paul J Giacobbe

Robert P Ryan

Sunil Gandhewar

Robert A Ciampa

Steven Van Seters

Marc D Sousa

Thomas A Lamaire

In general, techniques are described for automatically releasing network resources reserved for use by network devices within a network. In particular, a network device, such as a router, may include an interface card that receives a first and a second message from respective first and second client devices requesting reservation of network resources. The first message may include a first identifier, while the second message may include a second identifier. Both messages however may also include the same additional context information that identifies the same context in which the first client device operates. The router may include a control unit that determines whether the additional context information included within the first and second messages is the same. Based on a determination that this information is the same, the control unit may automatically release resources reserved for use by the first client device within the network.

Determining a subscriber device has failed gracelessly without issuing a DHCP release message and automatically releasing resources reserved for the subscriber device within a broadband network upon determining that another subscriber device requesting the reservation of a network address has the same context information as the failed subscriber device

A network is operated such that message forwarding traffic is shared among routers in a load-sharing set. The routers are respectively associated with different non-overlapping subspaces of a source address space from which source addresses of source nodes on the network are drawn, and each router has an identifier uniquely identifying the router in the load-sharing set. Address request messages identifying a predetermined forwarding route are broadcast on the network by source nodes, each request message containing a source address of the broadcasting node. In response to each address request message, each router determines whether the source address is within the address subspace associated with the router, and if so returns the router's identifier to the source node. When a message is to be transmitted from a source node to a destination node on another network via a router, the source node transmits the message on the network along with the identifier returned in response to the address request message broadcast by the source node. Each router forwards only those messages that contain the router's identifier.

Automatic load sharing for network routers

Quality of Service (&ldquo;QoS&rdquo;) variables for predetermined protocol Type data units are stored in a cache memory. For data units that are associated with a flow, thirteen bytes selected out of the Internet Protocol (&ldquo;IP&rdquo;) header are employed as at least a portion of a key to perform a cache lookup to obtain at least one Quality of Service variable from the cache. Both routing and QoS information may be stored in the cache for retrieval upon a single lookup operation.

Quality of service control mechanism and apparatus

A Receive Frame Processor (RFP) in a network bridge/router for receiving frame-characterizing information from other elements of the bridge/router and for generating plural code vectors which result in the selective processing of a received frame in software and/or hardware is provided. The received information is utilized in constructing code vectors representative of how a received frame is to be processed. Further data structures stored in conjunction with the RFP are indexed by the constructed code vectors and indicate whether the frame is to be processed in the RFP hardware, by software in an associated Frame Processor, or both. These data structures also indicate whether the port through which the frame was received is to be blocked to prevent misordering of received frames. If the frame is to be processed in software, the RFP generates a Receive Vector which is provided to the FP and which conveys the frame-characterizing code vectors to the FP. If the frame is to be processed in hardware by the RFP, a Transmit Vector is generated which contains information such as a mask of which transmit ports are to be utilized for forwarding the received frame, and information necessary for reconstructing a header for the received frame, including which encapsulation format is to be utilized for the frame.

Use of code vectors for frame forwarding in a bridge/router

A network bridge/router for identifying a data unit to be routed by a network bridge/router, for identifying a protocol associated with the received data unit to be routed, and for carrying out appropriate data unit transfer operations, all in hardware. A Receive Header Processor (RHP) analyzes the destination address of the received data unit, in hardware, for determining if routing or bridging is required. If routing is required, the RHP uses portions of the received data unit header as a compare value against predefined values stored in data structures which provide a protocol ID identifying the protocol of the received data unit and serving as an index to the appropriate microcode handling routine, executed by the RHP, for the data unit. The handling routine causes the RHP to forward data unit identifying information appropriate to the identified protocol and obtained from the received data unit to further hardware-based data unit processing elements. These further data unit processing elements are adaptable to the received data unit cast state (e.g. unicast, multicast, broadcast), bridging and/or routing requirements, and received data unit protocol.

Multiple protocol support

At least a portion of the data units in a bridge/router are processed by logic circuits according to cast type. The cast type, source address and destination address of an incoming data unit are determined by examining the header. For a unicast data unit, the source address and destination address are employed to obtain a transmit port indicator from memory, and the unicast data unit is directed to the port indicated by the transmit port indicator. For a non-unicast data unit, the source address and destination address are employed to obtain a first port mask that indicates valid ports for receipt of the data unit and a second port mask that indicates valid ports for transmission of the data unit from memory. The first and second port masks are combined to generate a third port mask, and the non-unicast data unit is directed to the ports indicated by the third port mask.

Unicast, multicast, and broadcast method and apparatus

At least a portion of the data units in a bridge/router device are analyzed for purposes of filtering by employing high speed logic circuits. A data unit is analyzed by such logic circuits by examining the header portion of the data unit, employing information obtained from the header portion to designate possible output ports for transmission of the data unit, examining a predefined per-port filter enable indicator to determine whether filtering is to be applied to the data unit, and applying filtering for each respective port for which the per-port filter enable indicator indicates that filtering is to be applied. Filtering is also implemented with logic circuits and executed at high speed. Filtering may be executed based on MAC address group, port group, combination MAC address and port group, protocol type, and non-unicast traffic frequency. Data units that cannot be analyzed by the logic circuits are analyzed by software.

Hardware filtering method and apparatus

Logic circuits are employed in a telecommunications bridge/router device to examine a received frame to determine which VLAN, if any, the frame is associated with. The protocol type, receive port identification, and receive VLAN tag are employed to determine the transmit port identification and transmit VLAN tag. A predefined table indicates which ports within the bridge/router are associated with the VLAN. The frame is excluded from transmission through the ports that are not associated with members of the respective the VLAN.

Growing community of inventors

Groton, MA, United States of America

William D Townsend