At+t Corp.

At&t Bell Laboratories

Lucent Technologies Inc.

Sandra S North

Bruce M Bales

Stephen M Thieler

Robert L Crumpley

David Lee Chavez, Jr

Lisa P Happel

Craig Steven Chapel

A communication switching system having a plurality of switch nodes with each of the switch nodes responsive to a failure of a communication link within a group of communication links to switch active calls from channels of the failed communication link to idle channels of other communication links within the group of communication links. If no idle channels are available within the group of communication links when the communication link fails, a predefined time is waited for a channel to become idle or a new communication link to be added to the group of communication links before the active channels are abandoned. Advantageously, the switching of the active calls to idle channels occurs quickly so that only a momentary interruption of the calls occurs. The group of communication links may advantageously be a non-facility access service (NFAS) group having a combination of ISDN BRI and PRI communication links. The calls can be either voice, video, or data calls.

Channel and data link automatic restoration

In a telecommunication switching system having a plurality of switch nodes with each of the switch nodes responsive to a failure of a communication link within a group of communication links to establish a flexible rate interface (FRI) link upon there being no spare channels within the group of communication links and to switch active calls from the channels of the failed communication link to the channels of the newly established FRI link. Advantageously, the group of communication links can be a non-facility access service (NFAS) group. Advantageously, this allows for additional B channels to be added to the NFAS group even though there are no remaining physical communication links between the two switch nodes being interconnected by the NFAS group. The establishment of the FRI link allows for the addition of B channels to the NFAS group with these B channels being routed through other switch nodes of the communication switching system. The FRI link becomes part of the NFAS group and control is provided for the B channels of the FRI link by the primary D channel of the NFAS group. Advantageously, the FRI link can be set up through other communication facilities other than the communication switching system. For example, if the two switch nodes interconnected by the NFAS group are both connected to the public telephone network, the FRI link can be set up through the public telephone network.

Establishment of a flexible rate interface link to restore channels from

A mobility management system and a traditional telecommunication switching system provide telecommunication terminal features by the mobility management system executing a software architecture that utilizes a unique terminal management application for each type of wireless terminal and a unique terminal emulator application for each type of telecommunication link that interconnects the mobility management system to the telecommunication switching system. There is an individually assigned telecommunication link for each wireless terminal. The terminal management applications and the terminal emulator applications communicate utilizing an internal message protocol. In response to a wireless terminal requesting actuation of a feature, a terminal management application converts that request into the required internal protocol messages and transmits the internal protocol messages to the terminal emulator application that controls the telecommunication link assigned to the wireless terminal. In response to the internal protocol messages, the terminal emulator application emulates the type of telecommunication terminal that normally would be connected to the assigned telecommunication link. The telecommunication switching system is responsive to the emulation to provided the requested feature as if telecommunication terminal was connected to the assigned link. The responses of the telecommunication switching system received via the assigned telecommunication link are converted to internal protocol messages and transmitted back to the terminal management application. The terminal management application converts and transmits the responses to the wireless terminal. The same internal protocol messages are used to invoke a particular feature regardless of the telecommunication terminal type or telecommunication link type.

Software architecture for providing communication features to different

A telecommunication protocol message that allows redirection of a call received by a first telephone station set to a second telephone station set or other terminal equipment by the first telephone station set transmitting the redirect message to a telecommunication system connected to the first telephone station set. The redirect message includes the identification of the user of the first telephone station set as well as the telephone number of the second telephone station set or terminal equipment. The telecommunication switching system is responsive to the redirect message to reroute a call to the second telephone set. The redirect message allows the first station set to transmit only one message to the telecommunication switching system to accomplish the functions of rerouting the call. In addition, the redirect message gives a BRI (basic rate interface) station set the capability of automatically forwarding certain types of calls. Since a call setup message includes the telephone number of the originating station set, the BRI station set can be programmed to transfer calls to different station sets based on the originating station number. In addition, with the proliferation of facsimile machines (often referred to as FAXs), there is a problem in coordinating an individual's telephone number with the individual's FAX number by a person wishing to send a FAX. Using the redirect message, the BRI station set can be programmed to examine the bearer capability information encoded as an Information Element, IE, in the setup message to determine the type of call that is being set up. If a digital data call is being set up, the BRI station set then examines the higher layer capability IE in the setup message to determine whether or not it is a FAX message. If it is a FAX message, the BRI station set will automatically forward the call to the FAX designated by the user of the BRI station set. Further, the station set will display a message indicating that a FAX message had been forwarded. Using this technique it is only necessary to know a person's telephone number in order to send a FAX to that person.

Redirection of calls by a communication terminal

Routing calls using a new protocol message which is a redirect message in a telecommunication system having a number of switching nodes to avoid circular paths among the switching nodes and for rerouting calls in the event of failures or overload conditions. During the establishment of a call from an originating switching node to a destination switching node where the call path has already been setup from the originating switching node through an intermediate switching node, a switching node is responsive to a setup message from the intermediate switching node requesting extension of the call path through the switching node to determine if such an extension would create a circular path. If circular path would be created, the switching node redirects the call (by using the redirect message) back to the intermediate switching node and indicates in that message to which switching node the call path should be extended. In response to the redirect message, the intermediate switching node reroutes the call path. Further, the redirect message entirely removes the call path between the switching node and intermediate switching node.

Rerouting in a distributed telecommunication system

A communication switching system having a plurality of switching nodes in which each switching node upon initialization completely establishes its own internal configuration. This establishment of internal configuration includes the number and type of switching modules and within each switching module: type of module control processor, type of internal switching network, printed board carriers, type and number of auxiliary circuits, and type and number of link interfaces. Each unit of a switching module reports relevant information to the module control processor; and in turn, the module control processor reports its own information and the information of the other units to a node processor (the main processor within a switching node). Further, each switching node and interfaces of the switching node automatically identifies the other switching nodes connected by communication links and switching paths to those switching nodes. Each interface upon being initialized automatically performs low level initialization operations over the connected link with the far end interface. The interfaces then report the completion of the initialization operations to the connected switching nodes. Upon receiving these reports, each switching node becomes aware of the existence of the links to other switching nodes. Each switching node then exchanges node numbers with the far end switching node connected via interfaces and communication links to establish the hierarchy of switching nodes in the switching system.

Automatic initialization of a distributed telecommunication system

A telecommunication switching system having switching nodes that perform adaptive routing by utilizing the fact that the switching nodes are arranged in a first and a second hierarchy. In addition, each switching node maintains routing information based on telephone and switching node numbers which identify the switching nodes. A destination switching node transfers its routing information back to an originating switching node which combines that routing information with its own in order to determine shorter call paths for subsequent call routing. The first hierarchy is a dialing plan hierarchy having groups of switching nodes at each dialing plan level. The second hierarchy is a switching node hierarchy based on the switching node number of each switching node with at least one switching node of the switching node hierarchy being at a different level in the dialing plan hierarchy. In order to route a call, a switching node first routes through levels of switching nodes in the dialing plan hierarchy until a second switching node is encountered which can determine the identification of the destination switching node based on a dialed telephone number. The second switching node then routes the call through the node hierarchy using the identified node number until a path is determined to the destination switching node.

Telecommunication switching system having adaptive routing switching

A system for distributing a numbering plan to switching nodes which are organized in a dialing plan hierarchy and for allowing an individual switching node to redistribute blocks of numbers to other switching nodes upon requests from those switching nodes to own the requested blocks of numbers. Further, the dialing plan hierarchy is automatically established upon system initialization with each switching node determining its position in that hierarchy. In addition, a switching node that needs to use only one number of a block owned by another switching node can request permission from the other switching node to use that telephone number for a telephone connected to the switching node. Such a use is referred to as hosting the telephone number. Hosting allows a telephone connected to one switching node to have a telephone number owned by another switching node and eliminates the constraint of requiring every telephone connected to a switching node to use a number from the block of numbers own by that switching node.

Telecommunication switching system having distributed dialing plan

A remote telecommunication terminal providing telecommunication functions identical to those functions provided by local telecommunication terminal directly connected to a telecommunications system via a direct standard link using a standard protocol. The remote telecommunication terminal is interconnected to the telecommunication system through an intervening switching system such as the public telephone network. One such remote telecommunication terminal is a remote telemarketing terminal. A remote telemarketing terminal cooperates with the telemarketing system to establish a virtual interface on the telemarketing system. The telemarketing system views this virtual interface as being identical to a physical interface such as one connected to a local telemarketing terminal via a standard link. The remote telemarketing terminal then establishes a virtual link between itself and the virtual interface on the telemarketing system. The virtual link is established on transport channels of standard links that interconnect the remote telemarketing terminal to the switching system and from the switching system to the telemarketing system. The switching system is unaware of the establishment of a virtual link on these transport channels and does not respond to signaling information on a virtual signaling channel of the virtual link.

Transparent signaling for remote terminals

A switching architecture with identical switching nodes having a topology which allows for multiple paths between any two endpoint switching nodes without intervening switching nodes being involved in call control on those paths. This architecture is made feasible by a new type of link, the flexible rate interface (FRI) link. The FRI link has its own signaling channel distinct from the signaling channel of a standard link and is transparent to intervening switching nodes. Only endpoint switching nodes are aware of the existence of the FRI link with respect to call control. A standard protocol is utilized on the signaling channels of both the standard link and the FRI link. Advantageously, the standard link may be an ISDN link and the standard protocol may be the ISDN protocol. An FRI signaling channel of the FRI link may be established by using any of the following: a B channel of a standard ISDN link, standard ISN user information transport facilities, or a logical link of a D channel of a standard ISDN link. In combination with the FRI signaling channel, the FRI link may utilize B channels from a number of standard ISDN links for FRI B channels.

Switching system using identical switching nodes

A switching architecture interconnecting remote switches to a central processor via standard links which may be set up through any number of intervening switching systems utilizing standard switching procedures. The standard links are ISDN links that may be set up dynamically via switching networks within the switching system or via the public switching network. The fact that an ISDN goes through a portion of the switching system or the public switching network is transparent to both the central processor and remote switch. Upon detecting that a primary central processor is no longer in control, each remote switch attempts to obtain an alternate path to the primary central processor. If a remote switch is unable to obtain an alternate path to the primary central processor, the remote switch switches to an alternate central processor on the assumption that the primary central processor has failed. Because the paths can be made on directly connected ISDN links, through the switching system, or through the public switching network to either the primary central processor or the alternate central processor, there is a high probability of a remote switch being able to obtain such a path.

Transparent remoting of switching network control over a standard

An apparatus for establishing a flexible rate interface (FRI) link on a standard ISDN link. The FRI link has its own signaling channel that is distinct from the signaling channel of the standard ISDN link, and the signaling channel of the FRI link is transparent to intervening switching systems. There are no geographical restrictions on a FRI link. The signaling channel of a FRI link may be established by designating a B channel of a standard link, by using a logical link of a D channel of a standard ISDN link, or by using standard ISDN user information transport facilities to communicate the signaling channel. FRI transport channels are B channels of a standard ISDN link or subchannels of a B channel.

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Sandra S North