Abstract: A method and system for encapsulating a frame for transport over an optical transport network are disclosed. A method includes receiving a packet at a network device and encapsulating the packet. The packet is received from a network having a line frequency different than a payload frequency of the optical transport network and the encapsulated packet is configured for transport directly over the optical transport network without modification to compensate for the different frequencies.

Abstract: A hierarchical traffic management system and method (i.e., a QoS behavioral model) are disclosed herein. The system includes a classifier operable to identify and classify incoming traffic streams and a queuing system. The queuing system includes a plurality of queues and is operable to apply scheduling policies to the traffic streams. The queues of the queuing system each include enqueue attributes configured to control a depth of the queue and dequeue attributes configured to control scheduling of the queue. The dequeue attributes include minimum bandwidth, maximum bandwidth, excess bandwidth, and priority, wherein each of the queues has one or more of the dequeue attributes defined.

Abstract: Methods and systems for preemption in a network having a core device with at least one egress interface are disclosed. In one embodiment, the method includes performing flow-based hash utilizing a plurality of hash-buckets each set to a first state or a second state and computing a load based on a rate measurement that excludes flows which hash into hash-buckets having a state set to the second state. The computed load is compared to a preemption threshold and if the computed load exceeds the preemption threshold, the state of at least one of the hash-buckets is changed from the first state to the second state. An action, such as dropping all packets or marking all packets, is performed on flows hashing in a hash-bucket in the second state.

Abstract: The systems and methods for incorporating an automatic retransmission mechanism into a point to multipoint network MAC layer that does not already incorporate retransmission are provided by virtue of one embodiment of the present invention. For example, the DOCSIS MAC layer protocol developed for data over cable networks may be modified to incorporate an automatic retransmission mechanism. This allows DOCSIS to be applied more effectively to communication channels such as the wireless communication channel.

Abstract: A method and apparatus for setting admission and preemption thresholds in a computer network are disclosed. In one embodiment, a method includes receiving traffic information including a first bandwidth utilization on each link located between ingress nodes and egress nodes based on a traffic matrix with no failures at the nodes or the links, and a second bandwidth utilization on each of the links based on the traffic matrix with planned failures at one or more of the links or the nodes. A preemption-to-admission ratio is calculated based on the first and second bandwidth utilizations on the links. An admission threshold is calculated at one of the links based on the second bandwidth utilization on the link and the preemption-to-admission ratio. At least one of the preemption-to-admission ratio and admission threshold is transmitted to a network device for use in flow admission.

Abstract: In one embodiment, a parallel batch reactor generally includes a plurality of reactor vessels and a plurality of valves configured to allow flow into the reactor vessels when a gas is supplied to the reactor at a pressure higher than a pressure within the reactor vessels and restrict flow from the reactor vessels. A method includes inserting chemical components into the reactor vessels, supplying a first gas to the reactor vessels to pressurize the reactor vessels, stopping supply of the first gas, and supplying a second gas to the reactor at a lower pressure than a pressure within the reactor vessels. The second gas passes through the valves and into the reactor vessels when the pressure within the reactor vessels drops below the pressure of the second gas.

Abstract: A method and system for emulating an Ethernet link over a Sonet path to provide link integrity is disclosed. The method generally includes receiving an error code at a local Ethernet port upon detection of a link failure at a remote Ethernet port. The error code is received over a Sonet path in a Sonet path overhead. If the error code is still present after a specified period of time, the local Ethernet port is disabled. Methods for providing link stability and link availability are also disclosed.

Abstract: LDP label switching may be discontinued gracefully on one or more selected ones of multiple links interconnecting a pair of label switched routers (LSRs) while leaving label switching in operation on the remaining LDP-enabled links. Mechanisms for graceful shutdown of LDP on a selected link are added by way of modification to one or more of: e.g., LDP discovery Hello messages, LDP Label Withdraw/Label Release messages, LDP Notification messages.

Abstract: Improved systems and methods for implementing data-driven protocols are provided. In one embodiment, improved implementations of multicast routing protocols are provided. Separation between multicast forwarding and control elements are provided by use of a powerful yet simple application program interface (API) for inter-module communication. The API is multicast-routing-protocol-independent and can be used to express the forwarding state of any existing multicast protocol. Efficient platform-specific implementations are facilitated.

Abstract: In one embodiment, a method for tracing a connection path from a source node to a destination node through a network having one or more transparent proxies includes generating a trace packet at the source node, transmitting the trace packet over the network towards the destination node, and receiving trace response packets in response to transmission of the trace packet. The trace response packets include a packet from the destination node and a packet from each of the transparent proxies in a data path from the source node to the destination node. Each of the packets from the transparent proxies includes an identifier of the transparent proxy transmitting the packet. The method further includes identifying the transparent proxies in the connection path based on information in the trace response packets. An apparatus for tracing a connection path is also disclosed.

Abstract: A method and system for performing route calculations in a link state routing protocol at a node within a computer network. The method includes evaluating existing routes of the node when new route information is received and recalculating routes for the node only when the new route information improves at least one of the existing routes or at least one of the existing routes is made worse or lost.

Abstract: Methods and apparatus for substantially minimizing single points of failure for circuit paths in networks with mixed protection schemes are disclosed. According to one aspect of the present invention, a method for routing circuit paths between a source and a destination of a network includes identifying a first available circuit path between the source and the destination. The first available circuit path includes a first plurality of links which each have an associated protection type. The method also includes determining a number protection changes associated with the first plurality of links, and assigning a first metric to the first available path that is based on the number of protection changes. Finally, the method includes identifying a selected available path to be used to pass information between the source and the destination based at least in part on the first metric.

Abstract: Methods and systems for identifying instability or a loop in a network. In one method, a first BPDU message is received at a switch indicating a topology change. The message includes a bridge identifier identifying a network device originating the first BPDU message. A second BPDU is generated at the switch and includes the bridge identifier identifying the network device originating the first BPDU message. The method further includes transmitting the second BPDU message indicating the topology change from the switch.

Abstract: Systems and methods for replacing software controlling active routers while minimizing impact on network operation are provided by virtue of one embodiment of the present invention. The software replacement process takes advantage of packet processor redundancy. An active packet switching device to be reprogrammed is de-activated and a redundant packet switching device takes over. The no longer active packet switching device is reprogrammed before being reactivated.

Abstract: A method and system for automatically interconnecting IPv4 networks across an IPv6 network are disclosed. The method includes receiving an IPv4 packet at an ingress router in the IPv6 network and finding the longest match IPv4 routing entry for IPv4 addresses in the received packet to identify an egress router in the IPv6 network. The IPv4 packet is encapsulated to create an IPv6 packet, wherein destination and source addresses of the encapsulated packet identify a subnet router anycast corresponding to the ingress router and the egress router in the IPv6 network. The encapsulated packet is forwarded to the egress router.

Abstract: A method and system for conveying management information across a network are disclosed. The method includes generating an Ethernet packet comprising a converged data link header in place of an Ethernet preamble and transmitting the modified packet from a network element. The header is configured to provide support for network management.

Abstract: A method for providing inter-ring protection in shared packet rings includes identifying an active node which is connected to a ring interconnect node on the same ring as the active node and connected to a peer node on a different ring with a ring interconnecting link. When the active node is in active mode and receives notification of a failure of the ring interconnecting link or peer node, the active node sends a message to the ring interconnect node so that the ring interconnect node switches from standby mode to active mode. The active node is then changed to standby mode.

Abstract: Systems and methods for computing the paths of MPLS Traffic Engineering LSPs across Autonomous System and/or area boundaries. A distributed path computation algorithm exploits multiple path computation elements (PCEs) to develop a virtual shortest path tree (VSPT) resulting in computation of an end-to-end optimal (shortest) path. In some implementations, the VSPT is computed recursively across all the Autonomous Systems and/or areas between the head-end and tail-end of the Traffic Engineering LSP.

Abstract: Systems and methods for interconnecting heterogeneous layer 2 virtual private network applications. To facilitate such interconnections, a common addressing scheme for forwarders is provided. All current pseudowire signaling protocols can incorporate this addressing scheme, and therefore establish connectivity among forwarders of different applications. Auto-discovery of remote forwarders is also facilitated by use of a common address family identifier (and subsequent address family identifier) for BGP.

Abstract: A flexible cross-connect with a data plane is presented which allows the establishment of connections between network interfaces at any network interface card to another network interface on any other network interface card. The system can cross-connect connections at an STS-1 and VT 1.5 granularity, and allows the switching and routing of information in a data plane without the use of the cross connect fabric. This permits routing, bridging, and concentration of data services to be performed without burdening of the cross connect. For reliability, a range of protection configurations can be employed including 1:1, 1:5 and mixed 1:N protection. A backplane is used which provides point-to-point traces between each card and the cross connect unit, between each card and a timing, communications and control unit, and between the network interface cards themselves.