Alcatel Lucent

Alcatel-lucent USA Inc.

Alcatel-lucent Canada Inc.

Peter Roberts

Kin Yee Wong

Kin-Yee Wong

Carl Rajsic

Ian Leighton

Kamakshi Sridhar

Hakki Cankaya

Shawn P McAllister

Mustapha Aissaoui

John Coffell

Mudashiru Busari

Ram Balakrishnan

Truc Le

Jason Walton

Shawn Mcallister

John Coffel

A method and system are provided for synchronizing local clocks more quickly in a telecommunication network using IEEE 1588. A network element that receives timing signals from one or more possible parent clocks considers a measure of the reliability of the timing signals contained in Announce messages from the parent clock or clocks. The clock uses this reliability information in selecting one of the possible parent clock or clocks to use as the actual parent clock. Once the selection is made, the clock adjusts the filtering characteristics applied to timing signals received from the selected parent clock. The adjustments reflect how confident the parent clock is as to how stable the timing information it provides has become. If the indication of reliability contained in Announce messages received from the parent clock indicates that the timing information is not very reliable, then a high filter bandwidth is used in filtering the timing signals. If the indication of reliability contained in Announce messages indicates that the timing information is reliable, such as by crossing a threshold, then the clock shifts to a normal low bandwidth filtering. By using reliability information in the Announce messages, clocks can better make selections as to which parent clock to use, and can use the reliability information to more quickly synchronize themselves with a grandmaster clock.

Faster synchronization time and better master selection based on dynamic accuracy information in a network of IEEE 1588 clocks

An intermediate clock, either a boundary or a transparent clock, may have to adjust its local clock to match that of a grandmaster clock. If such adjustment is frequent or large, then the intermediate clock may not have much confidence in the reliability of the timing information it passes to a downstream clock in an IEEE 1588 Announce message even if the quality of its local clock is high. The intermediate clock determines a measure of the reliability of its timing information. The intermediate clock inserts an indication of the reliability of the timing information in a transmitted IEEE 1588 Announce message. The intermediate clock may consider an indication of reliability found in an Announce message it receives when inserting an indication of the reliability of timing information into an Announce message which it transmits.

Distribution of dynamic accuracy information in a network of IEEE 1588 clocks

A method and system are provided for synchronizing local clocks more quickly in a telecommunication network using IEEE 1588. A network element that receives timing signals from one or more possible parent clocks considers a measure of the reliability of the timing signals contained in Announce messages from the parent clock or clocks. The clock uses this reliability information in selecting one of the possible parent clock or clocks to use as the actual parent clock. Once the selection is made, the clock adjusts the filtering characteristics applied to timing signals received from the selected parent clock. The adjustments reflect how confident the parent clock is as to how stable the timing information, it provides has become. If the indication of reliability contained in Announce messages received from the parent clock indicates that the timing information is not very reliable, then a high filter bandwidth is used in filtering the timing signals. If the indication of reliability contained in Announce messages indicates that the timing information is reliable, such as by crossing a threshold, then the clock shifts to a normal low bandwidth filtering. By using reliability information in the Announce messages, clocks can better make selections as to which parent clock to use, and can use the reliability information to more quickly synchronize themselves with a grandmaster clock.

A method and system are provided for improving maintenance of timing information when a node enters holdover due to a lost connection between a sub-network and a reference clock. Each node within the sub-network sends information concerning the drift of its local oscillator to a single node, and the single node uses this information to determine timing information for the entire sub-network. The single node may also use knowledge of the characteristics of the local oscillators. In this way, drift from the reference clock can be minimized without incurring significant added hardware costs.

Using multiple oscillators across a sub-network for improved holdover

A method and system are provided for allowing time-alignment of teleprotection measurements of power signals. Teleprotection observations are communicated between teleprotection ends through a packet switched network. At each end of a teleprotection segment, a teleprotection device communicates with the network through a router providing CES and located at the edge of the network. Clocks within the two routers are synchronized using IEEE 1588v2 signals. Using this synchronization, accurate one-way latency of data through the network between the two routers in each direction can be determined. The router at the incoming end of the faster path delays playout of packets by the difference between the two one-way latencies, thereby ensuring time-alignment of observations as they are sent from the routers to the teleprotection devices.

Symmetrical latency with TDM circuit emulated service

Communication network connection failure protection methods and systems are disclosed. Control information is communicated in a communication network, and causes network elements of the communication network to establish connection monitoring for respective segments of the network connection. Connection monitoring information which is communicated on the segments allows failures such as loss of continuity to be detected and reported. Responsive to an indication of a failure on a segment, the segment on which the failure occurred is identified, and the network connection can be rerouted around that segment.

Communication network connection failure protection methods and systems

A diagnostic tool is provided for calculating the availability of multi-segment pseudowires within an internet protocol (IP)-based mobile backhaul network. A control message is transmitted from an originating node towards a destination node within the IP-based mobile backhaul network over a primary multi-segment pseudowire and a secondary multi-segment pseudowire. From the response messages received from intermediate nodes positioned between the network node and the destination node along the primary multi-segment pseudowire and the secondary multi-segment psuedowire, the originating node determines the identities of each of the intermediate nodes, and calculates a respective individual availability of the primary multi-segment pseudowire and the secondary multi-segment pseudowire.

Tools that facilitate diagnostics for mobile backhaul networks

The invention is directed to providing a system and method for monitoring a clock synchronization metric in a timing-over-packet system to provide a metric for service-level agreements (SLA), by providing a measure of the stability of the packet transfer delay relative to a representative statistic such as a median or minimum.

Network impairment metrics for timing over packet

The invention is directed to a method and system for providing synchronization clock performance simulation in a timing-over-packet network having a network management system. The system retrieves information from nodes in a network and determines a timing-over-packet topology in a simulated model of the network, and determines clock stability statistics. The system further accepts simulation inputs such as addition or deletion of nodes in the simulated network, or introduction of failures into in the simulated network. The system provides predicted clock stability performance of an existing network under various simulated conditions without requiring modifications or introduction of failures to the existing network which would be useful for network optimization and network planning.

Network sync planning and failure simulations

The invention is directed to providing a method and system for monitoring and managing from a network management entity, timing-over-packet synchronization performance in a packet switching network having multiple network nodes. The network management entity determines a physical topology and a synchronization topology of the network and monitors synchronization performance by collecting virtual path information.

Network timing topology via network manager

The invention is directed to a method and system for providing centralized automated synchronization clock reconfiguration in packet switched telecommunications networks having network nodes that do not implement Synchronization Status Messaging (SSM) internally. This is especially useful when integrating TDM networks with packet switching network elements having T1 and E1 interfaces.

Centralized node clock auto reconfiguration

The invention is directed to a method and apparatus for providing improved packet over timing clock synchronization in a packet switching network using Operations, Administration, and Maintenance (OAM) tools to compensate for asymmetrical characteristics between forward and reverse data paths.

Timing over packet performance

Fully redundant clock systems are provided on network nodes coupled by redundant multisegment psuedowires (MSPWs) within an internet-protocol (IP)-based mobile backhaul network. The primary clock system includes a primary master clock on a first node and a primary slave clock on a second node coupled via a primary MSPW, while the secondary clock system includes a secondary master clock on the first node and a secondary slave clock on the second node coupled via a secondary MSPW. The primary and secondary slave clocks synchronize with their respective primary and secondary master clocks via their respective MSPWs. A clock controller maintains the secondary clock system in a hot-stand-by mode, and upon determining that a switch-over is needed, automatically switches from the primary clock system to the secondary clock system.

High availability clock synchronization and distribution for mobile backhaul networks

In source routed or hop-by-hop routed protocol communication networks, when congestion is detected at a certain network element, a notification message is sent to nodes. The nodes keep track of congestion condition and generally have knowledge of the congestion, thereby allowing them to make more intelligent routing decisions, i.e., rate controlling messages, routing traffic around congestion, regulating admission at the edge of the network. The intelligent routing decision is based on the congestion condition indicated by a restriction level which is periodically and dynamically updated.

Intelligent routing for effective utilization of network signaling resources

A method of distributing a common time reference within a distributed architecture includes one or more of the following: generating at least one electrical pulse at a central entity; distributing the at least one electrical pulse to a subassembly; receiving the at least one electrical pulse at the subassembly; recording a reception counter value corresponding to a value of a local frequency counter when the at least one electrical pulse is received at the subassembly; querying the central entity to obtain a generation time value corresponding to a time at which the at least one electrical pulse was generated; and determining a global time value using the generation time value, the reception counter value, and a current counter value of the local frequency counter.

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Stittsville, Canada

Peter Roberts