Abstract: Disclosed are various ways of performing reliable multicast communication which may include, for example, designating which node or nodes to acknowledge a message and/or whether to immediately acknowledge or delay acknowledgement of a message, which may be of particular use with routers, packet switching systems, computer systems, and other devices. Multiple nodes are typically sent a multicast message, which includes an indication of one or more designated nodes to acknowledge the message, a sequence number or other message identification value, and possibly an indication whether an immediate or delayed acknowledgment is requested. A node receiving the message responds accordingly if it is designated to acknowledge the message, which may include requesting any missing messages, and/or sending an acknowledgment message for the messages it has received since it sent its last acknowledgment message.

Abstract: Data path processing information is included in the pseudowire layer of pseudowire packets in order to provide information for use in the data path processing of data (e.g., a packet), typically, but not always, included in the payload of the pseudowire packet itself. The pseudowire packet typically includes in corresponding fields: a pseudowire label for identifying a pseudowire type; a pseudowire control word; and payload data. The pseudowire type identifies the structure of the pseudowire control word field and the payload field, including the location of data path meta data, such as in the pseudowire control word field or payload field. This data path meta data identifies one or more attributes for use in processing the payload data.

Abstract: Disclosed are, inter alia, methods, apparatus, computer-readable media, mechanisms, and means for interconnecting forwarding contexts using U-turn ports. A U-turn port typically comprises an egress port and an ingress port such that packets placed in the egress port are automatically forwarded to the ingress port. Other forwarding contexts are able to communicate packets to a next-destination forwarding context by sending these packets to the U-turn port of the next-destination forwarding context.

Abstract: Packets destined for the route processor of a packet switching device are rate controlled. Typically, line cards are configured to rate limit packets of offending packet flows destined for the route processor, such, but not limited to in response to a quantity of packets in the route processor. Filtering of packets of offending packet flows at the line cards reduces the work required of the route processor.

Abstract: A hierarchy of schedules propagate minimum guaranteed scheduling rates among scheduling layers in a hierarchical schedule. The minimum guaranteed scheduling rate for a parent schedule entry is typically based on the summation of the minimum guaranteed scheduling rates of its immediate child schedule entries. This propagation of minimum rate scheduling guarantees for a class of traffic can be dynamic (e.g., based on the active traffic for this class of traffic, active services for this class of traffic), or statically configured. One embodiment also includes multiple scheduling lanes for scheduling items, such as, but not limited to packets or indications thereof, such that different categories of traffic (e.g., propagated minimum guaranteed scheduling rate, non-propagated minimum guaranteed scheduling rate, high priority, excess rate, etc.) of scheduled items can be propagated through the hierarchy of schedules accordingly without being blocked behind a lower priority or different type of traffic.

Abstract: A packet switching device maintains mappings of bridge identification values to line cards for each of multiple virtual bridges. When a packet is received that includes a bridge identification value, corresponding line card(s) are identified, with each being forwarded the packet. Each of these identified line cards, in response to receipt of the packet from the line card, determines whether to forward or drop the packet based on its maintained bridge table. In this manner, the original receiving line card does not need to maintain forwarding information based on destination addresses of received packets (e.g., does not need to maintain a bridge table for each virtual bridge), but rather forwards a packet to other line cards associated with the virtual bridge corresponding to the bridge identification value received in a packet.

Abstract: A switching device (e.g., router, bridge) provides time-based authorization of multicast services. When a message is received to request the delivery of a multicast service or a first message is sent to a multicast group, a subscription policy for the IP multicast subscription service is retrieved. This subscription policy includes one or more limitations which allow the IP multicast subscription service during some predefined time of day/week or duration but prevent the IP multicast subscription service during some predefined time of day/week or duration. The switching device is configured to enforce these time-based authorization of multicast services policies.

Abstract: Policers receive packets of flows of packet traffic, which are to be communicated to monitored resource. The utilization levels of the monitored resource are induced by these flows of packet traffic. Based on the observed utilization levels (including possibly measured durations in one or more of these utilization levels), a determination is made if, and how to adjust policers for policing their respective flow, with policers being adjusted accordingly. In this manner, adaptive policers (typically located remotely from the monitored resource) are adjusted in response to one or more utilization levels (including possible durations at these utilization levels—i.e., a persistence of the congestion for the resource) of one or more monitored resources, with these identified utilization levels (and possibly durations) used in determining how much to modify a policing rate.

Abstract: The integrity of a control network for providing reliable communications between different entities is verified. Such a verified control network may be included in a device, system, or design library. The verification of a control network includes, but is not limited to: physically exercising the control network itself and/or its design via modeling, analysis, and/or applying or using other testing or design verification methodologies. For example, a Petri net model of the control network may be analyzed to verify that the control signals cannot be generated which could interfere with each other, that a deadlock condition cannot be reached, and that a control signal on an input port will result in a control signal on an output port, albeit possibly delayed.

Abstract: A graceful conversion of a security to a non-security transparent proxy is performed. A security transparent proxy is an intermediary between two end devices, with an established secure connection with each end device using different security keys. In response to a policy decision or other stimulus, the security transparent proxy is gracefully converted to a non-security transparent proxy such that it can forward, without decrypting and encrypting, the information received from a first endpoint on the first connection therewith to the second endpoint on the second connection therewith. This conversion is “graceful” in that it does not drop either of the two original sessions. In one embodiment, this graceful conversion is accomplished by triggering a key renegotiation on both of the two sessions such that the two connections will use the same encryption key.

Abstract: Route changes are processed and filtered to notify a client of those routing updates of interest to a client. In one configuration, a set of network addresses are received from a client indicating route updates of interest to the client and a set of types of routing changes that are of interest. One or more data structures are accordingly populated with this information. In response to receiving a route update, one or more lookup operations are performed on the data structure to identify whether this particular route is of interest to a particular client and/or whether any route dependent on the particular route are of interest to a client. The client is notified of the changes of interest. In one embodiment, the type of change to a route is also matched against a set of types of routing changes that are of interest, and a client is only notified if the change to a route of interest also matches a type of routing change of interest.

Abstract: Class-based bandwidth partitioning of a sequence of packets of varying packet classes is performed, such as, but not limited to determining whether or not to admit a packet to a queue based on a probability corresponding to a class of packets associated with the packet, with this probability being based on measured arrival traffic and a fair share based on the length of the queue. Data path processing is performed on each packet to determine whether to admit or drop the packet, and to record the measured received traffic. Control path processing is periodically performed to update these probabilities based on determined arrival rates and fair shares for each class of packets. In this manner, a relatively small amount of processing and resources are required to partition bandwidth for a scalable number of classes of packets.

Abstract: Disclosed are, inter alia, methods, apparatus, computer-storage media, mechanisms, and means associated with automated discovery of network devices supporting particular transport layer protocols, such as, but not limited to Stream Control Transmission Protocol (SCTP). Packet switching devices automatically discover peer packet switching devices supporting a particular transport layer protocol, and then establish a session using the particular transport layer protocol between them for subsequent use in transporting packets.

Abstract: A filtered Forwarding Information Base (FIB) (the “complete local FIB”) is used to determine how to forward packets, typically on line cards. The complete local FIB is generated by filtering (i.e., dropping or removing) extraneous entries in the standard global FIB of a router. This smaller FIB is then installed within the memory of a forwarding engine, possibly implemented as a single application-specific integrated circuit (ASIC), for use in determining how to forward packets, with the router forwarding packets accordingly.

Abstract: Disclosed are, inter alia, methods, apparatus, computer-storage media, mechanisms, and means associated with cooperative flow locks distributed among multiple components, such as on different application-specific integrated circuits in a packet switching device. Flow locks are typically used for maintaining the order of packets and operations performed thereon by the coordination of a context (e.g., the processing of a packet by a packet processor) with a corresponding flow lock interface, and by the manner of communication performed among the flow lock interface and the distributed flow locks.

Abstract: Disclosed are, inter alia, methods, apparatus, computer-storage media, mechanisms, and means associated with loss of reducing flooding in a bridged network, typically including a device directly connected to multiple upstream bridges. These bridges are configured such that the device receives broadcast/multicast traffic from a single interface of one of the bridges, while allowing unicast traffic over each of the communications links connecting the device to the bridges. In one configuration, the device implements virtual machine(s), each including a virtual network interface associated with a MAC address; and the directly connected bridges are configured, for each particular MAC address of these MAC addresses of the virtual interfaces, such that one and only one of the bridges will forward packets having the particular MAC address as its destination address over a communications link directly connected to the device.

Abstract: Disclosed are, inter alia, methods, apparatus, computer-readable media, mechanisms, and means for reducing packet flooding by a packet switch. A packet switch receives a flood prevention request message from an upstream router, with this message identifying a forwarding media access control (MAC) address and one or more destination MAC addresses of downstream routers. The packet switch looks up, typically in its forwarding data structure(s), these specified MAC addresses of the downstream routers in order to determine its corresponding ports on which to communicate with these MAC addresses. The packet switch updates its forwarding data structures accordingly such that a received multicast packet having as its destination MAC address the received forwarding MAC address will be forwarded out only these determined ports.

Abstract: Disclosed are, inter alia, methods, apparatus, computer-readable media, mechanisms, and means for communicating with a memory device, such as by a memory controller, a refresh command at least partially overlapping in time with a read and/or write command. The refresh command typically specifies a group of locations (e.g., a bank) for being at least partially refreshed.

Abstract: Disclosed are, inter alia, methods, apparatus, computer-storage media, mechanisms, and means associated with Bidirectional Forwarding Detection (BFD) on multilink bundled interfaces. A packet switching device communicates with another packet switching device through a multilink bundled interface configured for communicating over a plurality of bundled communication links. A separate BFD session is conducted over each link of the multiple bundled communication links, and in response to a BFD-detected failure condition, the use of the one or more links or the entire bundled interface is removed from service.

Abstract: Disclosed are, inter alia, methods, apparatus, data structures, computer-readable media, mechanisms, and means for a storage controller (e.g., memory controller, disk controller, etc.) performing a set of multiple operations on cached data with a no-miss guarantee until the multiple operations are complete, which may, for example, be used by a packet processor to quickly update multiple statistics values (e.g., byte, packet, error counts, etc.) based on processed packets. Operations to be performed on data at the same address and/or in a common data structure are grouped together and burst so that they arrive at the storage system in contiguous succession for the storage controller to perform. By not allowing the storage controller to flush the data from its cache until all of the operations are performed, even a tiny cache attached to the storage controller can reduce the bandwidth and latency of updating the data.