Abstract: A system may include a module that includes a component, a logic device to provide an instruction on behalf of the component, and control logic to generate a desired output voltage signal in response to a constant current, where the desired output voltage signal indicates a determined voltage that the component is configured to operate with when performing an operation. The system may include a board that includes a power supply to produce the determined voltage based on the instruction, and an interface to couple the determined voltage to the component to allow the component to perform the operation on behalf of the board, send the constant current to the control logic, and receive the desired output voltage signal from the control logic.

Abstract: A method performed by a network device may include assembling a multiprotocol label switching (MPLS) echo request, the echo request including an instruction for a transit node to forward the echo request via a bypass path associated with the transit node, and an instruction for an egress node to send an echo reply indicating that the echo request was received on the bypass path. The method may also include sending the MPLS echo request over a functioning label switched path (LSP).

Abstract: A packet header processing engine includes a memory having a number of distinct portions for respectively storing different types of descriptor information for a header of a packet. A packet header processing unit includes a number of pointers corresponding to the number of distinct memory portions. The packet header processing unit is configured to retrieve the different types of descriptor information from the number of distinct memory portions and to generate header information from the different types of descriptor information.

Abstract: Principles of the invention are described for providing multicast virtual private networks (MVPNs) across a public network that are capable of carrying high-bandwidth multicast traffic with increased scalability. In particular, the MVPNs may transport layer three (L3) multicast traffic, such as Internet Protocol (IP) packets, between remote sites via the public network. The principles described herein may reduce the overhead of protocol independent multicast (PIM) neighbor adjacencies and customer control information maintained for MVPNs. The principles may also reduce the state and the overhead of maintaining the state in the network by removing the need to maintain at least one dedicated multicast tree per each MVPN.

Abstract: A linked list traversal system identifies when a linked list has become inefficient, either through attack or an undue multiplicity of collisions. A data unit is parsed to extract a key. A first hash result associated with the key is calculated based on a first hash function. A first linked list is identified based on the first hash result. It is determined whether the first linked list has been compromised. A second hash result associated with the key is calculated based on a second hash function when the first linked list has been compromised. A second linked list is established based on the second hash result, where the second hash result is different from the first hash result.

Abstract: In general, techniques are described for summarizing label mappings and thereby enabling longest-prefix match within Multi-Protocol Label Switching (MPLS) networks. More specifically, a first router included within a first area of a network comprises a control unit that maintains a label space defining labels available for mapping to a plurality of addresses assigned to network devices within the network. The control unit reserves a contiguous set of the labels of the label space and maps the contiguous set of labels to first area addresses. The first area addresses include those addresses of the plurality of addresses available for assignment to network devices within the first area. The first router also includes an interface card that transmits, to a second router of a second area of the network, an advertisement that advertises a summarized version of the mapping between the contiguous set of labels and the first area addresses.

Abstract: A band control system for a digital subscriber line network in which a first apparatus and a second apparatus situated at a subscriber station and a center, respectively, are interconnected by a cable for interchanging at least a digital data signal with each other. The system may cause one of the first apparatus or the second apparatus to monitor receipt of signals from the other of the first apparatus or the second apparatus; send, based on a result of monitoring, a band variation command to the other apparatus for causing the other apparatus to vary a band by using a frequency band not used for signal transfer; cause the other apparatus to receive the band variation command; and vary the band in accordance with the band variation command.

Abstract: A network device is described in which a dedicated resource scheduler monitors memory consumption to provide for improved processing of communication sessions. The scheduler maintains a dependency list of communication sessions, and reserves memory for communication sessions as requests for memory are received. The amount of memory reserved is determined based on the amount of memory currently reserved for the communication sessions in the dependency list. The network device may control ongoing communication sessions by way of window manipulation. Communication sessions are processed in a first mode when available memory has not reached a predetermined amount, while communication sessions are processed in a second mode when available memory reaches a predetermined amount.

Abstract: A network device is described that concurrently executing more than one instance of an operating system on a single processor. Each of the instances of the operating system executes completely independent of the other instances. In this way, disparate instances may exist for the same operating system or for different operating systems. The techniques allow the processor to concurrently execute, for example, an instance of the operating system may emulate a routing engine and an instance of the operating system may emulate an interface controller. A hyper scheduler performs context switches between the operating systems to enable the processor to concurrently execute the instances of the operating system. The techniques may provide a low cost alternative to employing multiple processors within a network device, such as a router, to execute multiple independent operating systems.

Abstract: A network device includes a group of high speed redundant transmission lines and a switch. The switch is configured to select one of the high speed redundant transmission lines. The switch causes reflections and frequency dependent dispersions in the selected high speed redundant transmission line. The network device further includes a transmitting device that is configured to adjust signals transmitted over the selected high speed redundant transmission line so as to reduce the reflections and frequency dependent dispersions.

Abstract: A derived state value is calculated based on a plurality of component state values. As any of the plurality of component state values changes, the derived state value is recalculated. When sending information about a MAC address or other data between two components, the derived state value is included in the information sent. An object receiving a MAC address or other data from another object checks the validity of the received derived state value to determine whether to accept the new data and flush old data, to accept the new data, or to ignore the new data.

Abstract: Data units received by a network device may be classified into traffic flow classes in which the determined traffic flow class for a data unit may be dynamically refined as the data unit is processed by the network device. A dispatch component of the network device may receive data units associated with traffic flow classes. Parallel processing engines of the network device may receive the data units from the dispatch component and may generate, for a least one of the data units, a plurality of dynamically refined indications of the traffic flow class to which the data unit belongs. Additionally, an ordering component of the network device may include a plurality of re-order queues, where the at least one data unit successively progresses through at least two of the re-order queues in an order defined by the plurality of dynamically refined indications of the traffic flow class.

Abstract: A network device coordinates with other devices in a network to create a distributed filtering system. The device detects an attack in the network, such as a distributed denial of service attack, and forwards attack information to the other devices. The devices may categorize data into one or more groups and rate limit the amount of data being forwarded based on rate limits for the particular categories. The rate limits may also be updated based on the network conditions. The rate limits may further be used to guarantee bandwidth for certain categories of data.

Abstract: A device may receive a packet at a network device, and may retrieve from a table, by using information in a header of the packet as keys, records that include communication performance statistics associated with transport protocols. In addition, the device may select, based on the records, a transport protocol with an optimum communication performance statistics among the transport protocols and send the packet in accordance with the selected transport protocol from the network device.

Abstract: A call admission control technique allowing flexible and reliable call admissions at an ATM switch in the case of an ATM network including both QoS-specified and QoS-unspecified virtual connections is disclosed. In the case where a QoS (Quality of Service) specified connection request occurs, an estimated bandwidth is calculated which is to be assigned to an existing QoS-unspecified traffic on the link associated with the QoS-specified connection request. A call control processor of the ATM switch determines whether the QoS-specified connection request is accepted, depending on whether a requested bandwidth is smaller than an available bandwidth that is obtained by subtracting an assigned bandwidth and the estimated bandwidth from a full bandwidth of the link.

Abstract: A networking device, method, and web server software architecture are provided. The device may include a web server application program configured to run on an operating system of the device, and an event-based signaling mechanism configured to signal the web server application program when data has arrived on a socket of the operating system, by triggering an operating system-level signaling event. The web server application program is configured to read data off of the socket in response to detecting the event, without polling the socket first to determine that data is ready to be read from the socket.

Abstract: A data processing unit includes a chassis configured to contain a line card. The chassis defines, at least in part, a portion of a first flow pathway and a portion of a second flow pathway. The chassis is configured such that a first portion of a gas can flow within the first flow pathway between an intake region and the first end portion of the line card such that the first portion of the gas flows across a first end portion of the line card in a first direction. The chassis is configured such that a second portion of the gas can flow within the second flow pathway between the intake region and a second end portion of the line card such that the second portion of the gas flows across the second end portion of the line card in a second direction opposite the first direction.

Abstract: A software module operating within a router, such as an operating system, manages state information within a hierarchically ordered and temporally-linked data structure. The software module sends state change messages to other software modules within the router, referred to as consumers, in an order that corresponds to the hierarchical order and the temporal linking. The data structure may comprise a plurality of objects to store state information. The operating system may receive event messages that indicate a change to the state information. The objects may be hierarchically linked in accordance with a hierarchy representing relationships of event messages. The objects may be temporally linked in accordance with the order in which the operating system receives event messages. The operating system may traverse the data structure according to the temporal and hierarchical links to select state change messages to send to a consumer.

Abstract: A packet switching equipment and a switch control system employing the same performs operation of the switch core portion independent of content of decision of an arbiter portion and overall equipment can be constructed with simple control structure. The packet switching equipment includes input buffer portions temporarily storing packets arriving to the input ports and outputting packets with adding labels indicative of destination port numbers, a switch core portion for switching the packets on the basis of labels added to the input buffer portions, and an arbiter portion adjusting input buffer portions to provide output permissions for outputting to the output ports. A sorting network autonomously sorting and concentrating the packets on the basis of the labels added to the packets is employed in the switch core portion.

Abstract: A packet header processing engine receives a header of a packet. The received header includes a size of the packet. A maximum transfer unit size of a destination interface of the packet may be determined. The packet header processing engine determines whether the size of the packet exceeds the maximum transfer unit size of the destination interface. If the size of the packet does not exceed the maximum transfer unit size of the destination interface, the packet header processing engine generates a new header from the received header. If the size of the packet exceeds the maximum transfer unit size of the destination interface, the packet header processing engine generates a fragment header from the received header. The packet header processing engine may recycle the fragment header for further processing in addition to forming a first fragment packet from the fragment header.