International Business Machines Corporation

Nortel Networks Corporation

Cisco Technology, Inc.

Rockstar Bidco, LP

Cisco Systems Inc.

Anoop Ghanwani

Ken Van Vu

Gerald Arnold Marin

Brad Alan Makrucki

Andre N Fredette

Naganand Doraswamy

Clark Debs Jeffries

Loa Andersson

Norman Clark Strole

Donald Fedyk

Metin Aydemir

A computer network has a plurality of routers that deliver data packets to the network via a plurality of links. At least one router provides automatic protection switching in the event of a link failure. The at least one router includes a plurality of data interfaces for streams of data packets to enter and exit the at least one router; and a backup controller. The backup controller includes a backup path manager, a link monitor, and a backup packet processor. For at least one link of the routing node, the backup path manager identifies a backup routing path for forwarding affected data packets in the event of a failure of the at least one link. The link monitor monitors the plurality of links to determine when a link fails. When a link which has a backup routing path fails, the backup packet processor attaches backup routing path instructions to affected data packets routed over the failed link, and forwards the affected data packets via the backup routing path.

Automatic protection switching using link-level redundancy supporting multi-protocol label switching

A system, device, and method for establishing label switched paths across multiple autonomous systems involves establishing a label switched path in each autonomous system, and, at each shared border device, linking an incoming label switched path in an incoming autonomous system to an outgoing label switched path in an outgoing autonomous system. The Label Distribution Protocol is preferably used to establish the label switched path between border devices in each autonomous system. Each border device maps a label associated with the incoming label switched path to a label associated with the outgoing label switched path. When a border device receives a protocol message including the label associated with the incoming label switched device, the border device replaces the label in the protocol message with the label associated with the outgoing label switched path, and forwards the protocol message to the downstream neighboring (next hop) device in the outgoing autonomous system.

System, device, and method for establishing label switched paths across multiple autonomous systems

A router can consider two color vectors for a path including multiple links through a network. One color vector indicates colors that all of the multiple links include. Another color vector indicates the colors that none of the multiple links include. In setting up a constraint-based label switched path (LSP), a router can use a program that includes a logical process. With the process, the router can automatically compute the color vectors for the path whenever the path of an LSP changes and/or the characteristics (colors) of one or more of the multiple links constituting the LSP changes. Computing whether the path is eligible for inclusion in the LSP includes calculating whether the path includes all colors that must be included in an LSP and calculating whether the path includes any of the colors that must be excluded from the LSP.

Computing and using resource colors for composite links

A method and system within a telecommunications network for allocating available bandwidth among a plurality of sessions that share a common data link. First, a repeating unit time interval is designated for conducting the plurality of sessions. Next, the input flow rate from the source node of each of the sessions into the common data link is monitored. Thereafter, a target flow rate is computed and assigned to each of the sessions. The sum of the target flow rates is equal to the available bandwidth of the common data link. Finally, for each of the sessions in which the monitored input flow rate exceeds the assigned target flow rate, the source node is dynamically paused during each repeating unit time interval, such that the monitored input flow rate conforms to the assigned target flow rate for each of the sessions.

Enhanced flow control in ATM edge switches

A data transfer flow control system for a packet ATM communications system includes a plurality of nodes interconnected by transmission links. Available bandwidth allocation for data packets or cells is improved by defining a Nrm parameter to be the product of an allowable cell rate and a sampling period. Nrm is related to the number of data cells being transmitted between resource management cells in a transmission session, and is set to a number that is independent of round trip times between source and destination nodes, but varying with the allowable cell rate of the source. The allocation fairness problem is solved by normalizing the Nrm value to ensure that the inter-RM cell times for all sessions are fixed at a predetermined time interval. The selection of the predetermined time interval value is a trade-off between network overhead and the responsiveness of the traffic source to network congestion. The predetermined time interval is a function of link speed, buffer size and &ldquo;burstiness&rdquo; level of real time traffic sources.

Method and apparatus for allocation of available bandwidth

A data transfer flow control system for a packet communications system includes a plurality of nodes interconnected by transmission links. The rate at which a sender node transmits information to a destination node in a network is modified in accordance with congestion information returned to the sender node from nodes along the path of the transmission or from the information receiver. The rate change for information being sent from the sender node is modified based upon the amount of elapsed time occurring since the last rate change of the same type. In first and second examples, the rate change is implemented in accordance with exponential and linear relationships, respectively, between the modified flow rate and the elapsed time since the last rate change.

Method and apparatus for network flow control

A data transfer flow control system includes a plurality of nodes or switches in a network, which are interconnected by transmission links. Resource management cells are transmitted along with data cells in information transfer sessions. As the amount of session traffic at any node increases, the level of occupancy of the buffers for that node correspondingly increases to temporarily store overflow data. At every network node, a &ldquo;fair share&rdquo; cell rate is determined for each output transmission link. Whenever the current cell rate (CCR) of any session exceeds the fair share cell rate for the output link at a node, the buffer occupancy threshold values for setting congestion indication fields in the resource management cells are adjusted downwardly such that a lower threshold buffer occupancy will effect a traffic congestion setting for that session.

Method and apparatus for relative rate marking switches

A bin packing algorithm is employed to schedule computer network activities, such as pause times required for operation of an Ethernet network which implements existing IEEE 802.3x standards. In such a network, any node in the network can control the flow of traffic from upstream stations in order to avoid congestion at the flow-controlling node. Upon sensing congestion, the flow-controlling node determines how long each upstream node contributing to the congestion should pause transmission over the next control interval. In accordance with the invention, the pause times are scheduled or staggered by using the bin packing algorithm to sort the sources into one or more bins. One required bin property is that there is no overlap in pause times for the sources within a particular bin. Another required bin property is that the sum of the pause times within a bin can be no greater than the length of the control interval. In a preferred embodiment, the calculated pause times are separated into different groups having different number ranges and no more than one pause time is selected from any particular group for packing into a given bin.

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North Billerica, MA, United States of America

Anoop Ghanwani