A telecommunications switching system employing multi-protocol routing optimization which utilizes predetermined and measured parameters in accordance with a set of user priorities in determining the selection of a telecommunications path to be utilized for transmitting a data file to a remote destination. The switching system has a first memory for storing the data file to be transferred, a second memory for storing predetermined parameters such as cost data associated with each of the telecommunications paths, a third memory for storing a set of user priorities regarding the transmission of data files, and means for measuring the value of variable parameters such as file transfer speed associated with each of the telecommunications paths. Processor means are operatively associated with the second and third memories and the variable parameter measuring means for determining which of the plurality of telecommunications paths should be utilized for transferring the data file in accordance with the set of user priorities, the predetermined telecommunications path parameters, and the measured variable parameters. The switching system further comprises input means for allowing a user to change the user priorities in the third memory prior to transmitting a file.

Multi-protocol telecommunications routing optimization

An integrated digital loop carrier (IDLC) system includes digital line feeders and signal processors to interface with the feeders an to ultimately provide data to subscriber instruments. The system can be employed as a central office terminal (COT) or remote digital terminal (RDT) with analog, T1 or SONET feeders and any conventional link medium. Data are put in DS1 format and multiplexed onto token ring optical loops for delivery to banks of channel units wherein the optical signals are translated to electrical signals for delivery to the Cus and subscribers. A method and apparatus is provided for mapping and demapping signals between virtual tributaries (VT) and digital signal formats in the RDT of an integrated digital loop carrier. An application-specific circuit provides such mapping and demapping functions as Floating Byte Synchronous VT to Locked Byte Synchronous VT, Floating Asynchronous VT to Locked Byte Synchronous VT, Floating Asynchronous VT to Floating Asynchronous VT, DS1 to Locked Byte Synchronous VT, DS1 to Floating Asynchronous VT, and DS1 to Floating Byte Synchronous VT.

Integrated digital loop carrier system with virtual tributary mapper circuit

A modular, expandable, non-blocking system for cross-connecting high speed digital signals is provided. The system is capable of connecting DSn, CEPTn, and STSn signals as desired, with lower rate signals being included as components of the high-rate signals or terminating on low speed lines, as desired. The system accomplishes its goals by converting all incoming signals into a substantially SONET format, and by processing all the signals in that format. The signals are typically cross-connected in the substantially SONET format, although an expandable non-blocking wide band cross-connect module is provided which cross-connects any like signals. If the outgoing signal is to be in other than SONET format, the substantially SONET formatted signal is reconverted into its outgoing format. To create a complete system, various modules are utilized, including: add/drop multiplexer means for add/drop applications of DS-0, DS-1, CEPTn signals, etc.; a SONET bus interface; a virtual tributary cross-connect module which cross-connects virtual tributary payloads in space, time, and phase to generate new substantially SONET formatted signals; a wide band cross-connect module; a DS-3/SONET converter; and front end interfaces including a DS3 line interface, and various STSn interfaces. The modules may be mixed and matched as desired to accommodate a multitude of applications.

System for cross-connecting high speed digital signals

A method and apparatus is provided for automatic protection switching in a ring network by creating a protection domain having a control vlan and protected data vlans and designating a master node and transit nodes connected by a primary port and a secondary port. The master node blocks the secondary port for data vlan traffic until it detects a fault either by notice from a transit node or by polling. When a fault is detected, the master node unblocks the secondary port for data vlan traffic. When the fault is restored, the transit node temporarily blocks the restored port to data vlan traffic thereby preventing a loop. Each time the secondary port is blocked and unblocked, the forwarding databases on all the nodes are flushed.

Ethernet automatic protection switching

In a ring topology network, a number of nodes interconnect transmission links to form first and second working rings and first and second optical protection rings in a ring topology. Multiple working paths are established on each working ring and multiple protection paths are established on each protection ring corresponding to the working paths. A first working path spans across first and second nodes for transmission of a signal in a first direction of the ring topology, and a second working path of the second working ring spans across the first and second nodes for transmission of a signal in a second direction of the ring topology opposite to the first direction. A first protection path on the first protection ring spans across the first and second nodes for transmission of a signal in the second direction of the ring topology, and a second protection path of the second protection ring spans across the first and second nodes for transmission of a signal in the first direction of the ring topology. The first and second nodes normally use the first and second working paths, respectively. Responsive to a failure of one of the first and second working paths, the first and second nodes use a corresponding one of the first and second protection paths, instead of the failed working path.

Ring network for sharing protection resource by working communication paths

A transmission system comprises nodes coupled in a ring via two multiplexed transmission paths having opposite transmission directions. The two paths can be time, space, or wavelength division multiplexed. Bidirectional communications between any two nodes are provided in normal operation using both paths around a first, most direct, part of the ring. In the event of a fault affecting such communications, a protection switch is made to maintain bidirectional communications between the two nodes using both paths around a second, remaining, part of the ring. In this manner, each path can simultaneously carry both normal and protection switched signals. In an embodiment of the invention, only the two nodes adjacent a fault need be aware of the fault, each of these nodes effecting a protection switch for signals terminated at the node and effecting a protective loopback for other signals needing protection. The invention enhances the total capacity of the paths for carrying normal and protection switched signals. A network may comprise a plurality of such ring transmission systems intersecting at at least one network node, the network node comprising a node of each ring and a cross connect switch for switching signals therebetween.

Ring transmission system

In a synchronous network, asynchronous data signals are synchronized using positive/negative stuffing under the control of stuff request signals which are produced in dependence upon the phase difference between the asynchronous and synchronized data signals as compared to respective threshold values. The phase difference is, or the threshold values are, cyclically changed in a manner to produce additional stuffing, not necessitated by the asynchronous frequency difference, whereby the frequency of jitter, due to stuffing, in the synchronized data signal is increased. The increased frequency jitter is filtered out in an already-provided phase locked loop.

James Angus Mceachern

Papers

Ring transmission system

Synchronization of asynchronous data signals