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: Methods, apparatus, and products for routing frames in a shortest path computer network for a multi-homed legacy bridge, wherein the network includes a plurality of bridges. At least two of the plurality of bridges operate as edge bridges through which the frames ingress and egress the network. A first edge bridge identifies a legacy bridge nickname for a legacy bridge connected to the network through the first edge bridge and a second edge bridge using active-active link aggregation. The first bridge receives a frame from the legacy bridge and determines, in dependence upon the frame's destination node address, an egress bridge nickname for a third bridge through which a destination node connects to the network. The first bridge then adds the legacy bridge nickname and the egress bridge nickname to the frame and routes the frame to the third bridge in dependence upon the egress bridge nickname.

Abstract: A method may include receiving a packet including a destination address, identifying a destination address entry based on the destination address, the destination address entry including an address identifier, comparing the address identifier to an event identifier, determining whether an event occurred based on the comparison, and forwarding the packet on an alternate path if it is determined that the event occurred.

Abstract: Methods, apparatus, and products are disclosed for forwarding frames in a computer network using shortest path bridging (‘SPB’). The network includes multiple bridges, and each edge bridge is assigned a unique service virtual local area network (‘VLAN’) identifier. One of the bridges receives a frame for transmission to a destination node. The received frame includes a service VLAN identifier for the ingress bridge through which the frame entered the network and a customer VLAN identifier. The one bridge identifies an SPB forwarding tree in dependence upon the service VLAN identifier. The SPB forwarding tree specifies a shortest route in the network from the ingress bridge through the one bridge to the other bridges in the network. The one bridge then forwards the received frame to the egress bridge without MAC-in-MAC encapsulation in dependence upon the SPB forwarding tree and the customer VLAN identifier.

Abstract: Methods, apparatus, and products are disclosed for routing frames in a TRILL network using service VLAN identifiers by: receiving a frame from an ingress bridge node for transmission through the TRILL network to a destination node that connects to the TRILL network through an egress node, the received frame including a customer VLAN identifier, a service VLAN identifier uniquely assigned to the ingress bridge node, and a destination node address for the destination node, the received frame not having mac-in-mac encapsulation; adding, in dependence upon the service VLAN identifier and the destination node address, a TRILL header conforming to the TRILL protocol, the TRILL header including an ingress bridge nickname and an egress bridge nickname; and routing, to the egress bridge node through which the destination node connects to the network, the frame in dependence upon the ingress bridge nickname and the egress bridge nickname.

Abstract: Methods, apparatus, and products are disclosed for routing frames in a TRILL network using service VLAN identifiers by: receiving a frame from an ingress bridge node for transmission through the TRILL network to a destination node that connects to the TRILL network through an egress node, the received frame including a customer VLAN identifier, a service VLAN identifier uniquely assigned to the ingress bridge node, and a destination node address for the destination node, the received frame not having mac-in-mac encapsulation; adding, in dependence upon the service VLAN identifier and the destination node address, a TRILL header conforming to the TRILL protocol, the TRILL header including an ingress bridge nickname and an egress bridge nickname; and routing, to the egress bridge node through which the destination node connects to the network, the frame in dependence upon the ingress bridge nickname and the egress bridge nickname.

Abstract: Methods, apparatus, and products for routing frames in a network using bridge identifiers, wherein the network includes a plurality of bridge nodes. At least one of the bridge nodes operates as an ingress bridge node through which frames are received into the network. At least one of the bridge nodes operates as an egress bridge node through which frames are transmitted out of the network. One of the bridge nodes receives, from the ingress bridge node, a frame for transmission to a destination node. The destination node connects to the network through the egress bridge node. The frame includes an ingress bridge identifier and an egress bridge identifier. The bridge that received the frame then routes the frame to the egress bridge node through which the destination node connects to the network in dependence upon the ingress bridge identifier and the egress bridge identifier included in the frame.

Abstract: Managing routes in a router involves the implementation of threshold-specific discard algorithms to discard redundant routes in an intelligent fashion based upon the volume of routes in the router. By employing threshold-specific discard algorithms to intelligently discard redundant routes within a router, the storage capacity of the router is utilized in a more efficient fashion because the routes are not dropped indiscriminately. A method and system comprise identifying a volume of routes in the router, determining whether the volume of routes has reached a threshold and applying a threshold-specific discard algorithm to routes in the router if the volume of routes has reached the threshold.

Abstract: An efficient mechanism for wire-tapping network traffic is disclosed. In one embodiment of the invention, a primary forwarding lookup process and a secondary forwarding lookup process are performed in parallel and independently of each other. The primary forwarding lookup process determines the output interface to which the packet is to be routed regardless of whether the packet is to be intercepted. The secondary forwarding lookup process determines whether the packet is to be intercepted and also determines the output interface to which a copy of the packet is to be routed. Because the lookup processes are performed independently and in parallel, normal packet forwarding can be performed at line rate or near line rate while the packets are intercepted.

Abstract: A method may include receiving a packet including a destination address, identifying a destination address entry based on the destination address, the destination address entry including an address identifier, comparing the address identifier to an event identifier, determining whether an event occurred based on the comparison, and forwarding the packet on an alternate path if it is determined that the event occurred.

Abstract: A method for filtering and selectively displaying log messages generated by a network node with a distributed architecture is disclosed. In one embodiment, log messages generated locally on the line cards are collected by Secondary Log Managers residing on the line cards. The Secondary Log Manager appends meta data to the collected messages and transfers at least part of them to a Primary Log Manager process residing at the control module. Using the meta data, the Primary Log Manager can selectively output the logging and tracing messages interested Command Line Interface (CLI) shells or output devices.

Abstract: A technique for managing traffic in a multiport network node involves establishing customer-specific VLANs within the multiport network node that are identified by a combination of a VLAN ID and a customer ID. Traffic received at the multiport network node is mapped to a customer-specific VLAN and then broadcast to ports that are included in the customer-specific VLAN. Because customer-specific VLANs are identified by a combination of a VLAN ID and customer ID, a service provider can establish and maintain private broadcast domains on a per-customer ID basis. This enables the service provider to expand the number of unique VLAN IDs within the Service Provider Edge Device beyond the 4,096 limitation set by the IEEE 802.1Q standard while maintaining interoperability with the IEEE 802.1Q standard for incoming and outgoing traffic.

Abstract: A technique for implementing VLANs across a service provider network involves establishing logical ports that have bindings to transport tunnels. The logical ports are then treated the same as physical ports in defining broadcast domains at particular service provider edge devices. Logical ports can be established for Layer 2 transport tunnels that use stacked VLAN tunneling and MPLS tunneling. Establishing a logical port that uses stacked VLAN tunneling involves binding a physical port and a stacked VLAN tunnel to the logical port. Establishing a logical port that uses MPLS tunneling involves binding an MPLS tunnel to a logical port. In one embodiment, the logical port is bound to a static MPLS tunnel and in another embodiment, the logical port is bound to a dynamic MPLS tunnel and the destination IP address of the destination service provider edge device.

Abstract: Synchronizing multiple instances of an FIB in a network node that has a distributed processing architecture involves associating sequence numbers with all of the FIB entries that are stored with each instance of the FIB and using the sequence numbers that are associated with the FIB entries to determine the most current FIB entry. In one embodiment, the sequence numbers are used to determine the most current FIB entry among two matching FIB entries that have matching information (i.e., matching destination IP addresses and masks). In another embodiment, the sequence numbers are used to identify a line card with the most current FIB entry.

Abstract: A concept of “Interface Class” is introduced. All logical interfaces that belong to an Interface Class are indistinguishable in hardware. Each Interface Class is associated with one or more packet forwarding rules, such as Access Control Lists (ACLs), Policy Routes, and Quality of Service (QoS). Each Interface Class is also assigned with a Class ID, which is a user-defined integer. When defined in terms of a Class ID, a logical interface (e.g., an L3 Interface) will inherit all the packet forwarding rules associated with the Class ID. In one embodiment, Class IDs and Interface IDs can be stored in the same hardware lookup table in association with data representative of their respective packet forwarding rules.

Abstract: A method of operating a network node in PIM-SM (Protocol Independent Multicast-Sparse Mode) is disclosed. In one embodiment, a Rendezvous Point Tree (RPT) to Shortest Path Tree (SPT) switch over process is initiated after the packet flow rate of the RPT data stream is compared against a predetermined threshold using a reverse rate limiting technique. If the packet flow rate of the RPT data stream exceeds the threshold, further analysis can be performed to decide whether the RPT to SPT switch over process should be initiated. Otherwise, if the packet flow rate does not exceed a predetermined threshold, the network node continues to receive multicast packets via the RPT until the predetermined threshold is reached.

Abstract: Rate-limiting a traffic stream using a rate-limit hierarchy involves subjecting a packet to a first rate-limit check, the first rate-limit check corresponding to a first-level traffic classification, subjecting the packet to a second rate-limit check and an infinity rate-limit cheek, the second rate-limit check and the infinity rate-limit check corresponding to a second-level traffic classification, granting an automatic pass to the packet from the infinity rate-limit check regardless of whether or not the packet passes the second rate-limit check, and granting an overall pass of the rate-limit hierarchy if the packet passes the first rate-limit check. In an embodiment, the first-level traffic classification is a parent classification of the second-level traffic classification and the second-level traffic classification is a child classification of the first-level traffic classification.

Abstract: Distributing forwarding information in a router that has a distributed processing architecture involves distributing the forwarding information from one instance of an operating system to another instance of an operating system in parallel using two different communications channels where one of the communications channels is characteristically reliable yet relatively slow and where the other one of the communications channels is characteristically unreliable yet relatively fast. The forwarding information that is distributed via the relatively fast communications channel can be used to rapidly update forwarding tables such as hardware forwarding tables while the forwarding information that is distributed via the reliable communications channel can be used to resolve errors that may occur during distribution via the relatively fast communications channel.

Abstract: Performing cascading lookups at a network node involves using first header information from a packet to search a first set of search criteria for a match, identifying a tag associated with the match, and using second header information from the packet and the tag to search a second set of search criteria for another match.

Abstract: An efficient Reverse Path Forwarding (RPF) check mechanism is disclosed. In one embodiment, when a network node receives a multicast packet on an incoming interface, the network node obtains an expected incoming interface identifier from either a unicast routing table or a multicast forwarding information table. A RPF Flag stored in association with multicast flow information determines from which table the interface identifier is obtained. If the expected incoming interface does not match the actual incoming interface, the multicast packet is discarded.