Cisco Technology, Inc.

Cabletron Systems, Inc.

Digital Equipment Corporation

Compaq Computer Corporation, Inc.

Enterasys Networks, Inc.

Hewlett-packard Development Company, L.P.

At+t Corp.

Caldetron Systems, Inc.

Anna Charny

Francois Le Faucheur

Jean-Philippe Vasseur

Robert C Olsen

Christopher J Kappler

Earl T Cohen

Alton Lo

Carol Etta Iturralde

Robert Goguen

Robert E Thomas

Kadangode K Ramakrishnan

Peter J Roman

Robert J Simcoe

Anthony G Lauck

Wing Cheung

Naimish Patel

Pattabhiraman Krishna

Alon Shlomo Bernstein

Sandeep Bajaj

K K Ramakrishnan

Hani El-Sakkout

Prashant Pai

Barry Richards

Clarence Filsfils

Stewart Frederick Bryant

George Swallow

Ian Michael Charles Shand

Mohammed Ismael Tatar

Doron Shoham

John William Evans

Bruce Stuart Davie

David J Tsiang

Robert H Thomas

Prabhu Vaithilingam

Alex E Raj

John Bettink

Mohammed Azhar Sayeed

David Getchell

Xinyang Zhang

Elisheva Hochberg

Robert James Goguen

Jean Philippe Vasseur

Christopher Kappler

In one embodiment, a primary tunnel is established from a head-end node to a destination along a path including one or more protected network elements for which a fast reroute path is available to pass traffic around the one or more network elements in the event of their failure. A first path quality measures path quality prior to failure of the one or more protected network elements. A second path quality measures path quality subsequent to failure of the one or more protected network elements, while the fast reroute path is being used to pass traffic of the primary tunnel. A determination is made whether to reestablish the primary tunnel over a new path that does not include the one or more failed protected network elements, or to continue to utilize the path with the fast reroute path, in response to a difference between the first path quality and the second path quality.

Technique for determining whether to reestablish fast rerouted primary tunnels based on backup tunnel path quality feedback

In one embodiment, a set of tunnels is determined that traverse a particular link connected to an intermediate node in a network. The intermediate node computes, in a coordinated path computation, paths for tunnels of the set of tunnels that do not include the particular link. The coordinated path computation considers each of the tunnels of the set of tunnels. The intermediate node selects one or more tunnels of the set of tunnels for preemption. The one or more tunnels are selected as tunnels that are reroutable by respective head-end nodes of the one or more other tunnels. Notifications are sent to one or more other intermediate nodes that inform the one or more other intermediate nodes of the one or more tunnels selected for preemption.

Optimization of distributed tunnel rerouting in a computer network with path computation at an intermediate node

In one embodiment, an apparatus generally comprises one or more input interfaces for receiving a plurality of flows, a plurality of output interfaces, and a processor operable to identify large flows and select one of the output interfaces for each of the large flows to load-balance the large flows over the output interfaces. The apparatus further includes memory for storing a list of the large flows, a pinning mechanism for pinning the large flows to the selected interfaces, and a load-balance mechanism for selecting one of the output interfaces for each of the remaining flows. A method for local placement of large flows to assist in load-balancing is also disclosed.

Local placement of large flows to assist load-balancing

In one embodiment, a node determines an overload ratio for an output as a ratio of a total rate of received traffic at the output to a preemption threshold of the output. The node also determines a ratio of traffic that is to be marked at the output based on the overload ratio and a ratio of previously marked traffic destined for the output from each input to the total traffic from each input to the output, and whether, for a particular input, the ratio of previously marked traffic is less than the ratio of traffic that is to be marked at the output. If so, the node marks unmarked traffic of the particular input corresponding to a difference between the ratio of traffic that is to be marked at the output and the ratio of previously marked traffic destined for the output from the particular input.

Control of preemption-based beat-down effect

In one embodiment, an apparatus includes a processor for mapping packets associated with network flows to policy profiles independent of congestion level at the apparatus, and enforcing the policy profiles for the packets based on a congestion state. Packets associated with the same network flow are mapped to the same policy profile and at least some of the network flows are protected during network congestion. The apparatus further includes memory for storing the policy profiles. A method for protecting network flows during network congestion is also disclosed.

Protection of network flows during congestion in a communications network

In one embodiment, an intermediate node computes paths for a set of tunnels that do not include a particular link (e.g., and possibly a scaled-down bandwidth for each tunnel), considering all of the tunnels of the set. The intermediate node informs head-end nodes of the tunnels of the computed paths (e.g., and scaled bandwidth) and/or a time to reroute the tunnels.

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.

Propagation of minimum guaranteed scheduling rates among scheduling layers in a hierarchical schedule

In one embodiment, a node receives packets from one or more input interfaces, and may place the packets in an appropriate output queue for a corresponding output interface. The node may also place received unmarked packets from each of the input interfaces in a corresponding virtual queue of a virtual scheduler for the corresponding output interface. The virtual scheduler may be served at a configured rate, and any unmarked packets in the virtual queue that exceed a configured threshold may be marked.

A method and system for automatically generating a route distinguisher for a virtual private network are disclosed. The method includes receiving a virtual private network name and rejecting the virtual private network name if the name comprises a number of bytes greater than a predefined limit. If the virtual private network name is less than the predefined limit, an algorithm is applied to automatically convert the virtual private network name to a route distinguisher for the virtual private network.

Method and system for automatic generation of route distinguishers for virtual private networks

Schedules may use burst tolerance values to adjust the scheduling in a time-based schedule, such as, but not limited to, adjusting for accumulated but not used bandwidth, and/or adjusting eligibility of schedule entries. A best schedule item associated with an eligible schedule entry of a schedule is identified. Whether or not a particular schedule entry is eligible is typically determined based on the relationship of an associated timestamp with a current scheduling time, such as its timestamp being less than or equal to the current time. A burst tolerance time bound might also be used to allow certain priorities and/or types of items to be considered eligible if even its timestamp exceeds the current time by an amount, but less than or equal to the burst tolerance time bound. When a schedule entry which has been dormant becomes active, its one or more timestamps are typically initialized, which may include setting at least one of these timestamps behind current time by a wakeup burst tolerance value to guarantee its immediate eligibility for one or more consecutive scheduling iterations.

Using burst tolerance values in time-based schedules

A technique dynamically determines whether to reestablish a Fast Rerouted primary tunnel based on path quality feedback of a utilized backup tunnel in a computer network. According to the novel technique, a head-end node establishes a primary tunnel to a destination, and a point of local repair (PLR) node along the primary tunnel establishes a backup tunnel around one or more protected network elements of the primary tunnel, e.g., for Fast Reroute protection. Once one of the protected network elements fail, the PLR node 'Fast Reroutes,' i.e., diverts, the traffic received on the primary tunnel onto the backup tunnel, and sends notification of backup tunnel path quality (e.g., with one or more metrics) to the head-end node. The head-end node then analyzes the path quality metrics of the backup tunnel to determine whether to utilize the backup tunnel or reestablish a new primary tunnel.

Various techniques are disclosed for managing traffic flow for transport over a plurality of communication channels of a shared access cable network. According to various embodiments, one or more devices of the cable network (such as, for example, a Cable Modem Termination System (CMTS)), may be operable to implement at least a portion of the traffic flow management techniques. In at least one embodiment, one or more aspects of the traffic flow management techniques disclosed herein may be used for performing real-time shaping of traffic flows across multiple different channels of a DOCSIS channel bonding group. In some embodiments, various different traffic shaping and/or traffic scheduling techniques may be employed (e.g., in DOCSIS 3.0 compatible cable networks) to reduce and/or mitigate issues which, for example, may arise as a result of an inability to represent traffic schedulers as tree-based hierarchies. Other aspects are disclosed for implementing quality of service (QoS) procedures on shared access network(s), such as for example hybrid fiber/coaxial (HFC) cable networks.

Traffic flow scheduling techniques implemented on bonded channels of a shared access cable network

QoS on bonded channels of a shared access cable network

Growing community of inventors

Sudbury, MA, United States of America

Anna Charny