Multiplex communications – Pathfinding or routing – Switching a message which includes an address header
Reexamination Certificate
1998-02-19
2001-07-10
Chin, Wellington (Department: 2604)
Multiplex communications
Pathfinding or routing
Switching a message which includes an address header
C370S457000
Reexamination Certificate
active
06259697
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a system and method for switching permanent virtual connection (PVC), and, more particularly, to a system and method for controlling switching of PVC in an asynchronous transfer mode (ATM) switching network.
2. Description of the Related Art
Generally, the PVC is a connection path in which an originating terminal and a terminating terminal, or parties to be connected are fixed. When setting of the PVC path or the like is modified, it is necessary to modify setting by individual PVCs to be modified every time modification occurs. Thus, to enhance efficiency of the modification, it is sufficient to previously provide a plurality of settings such as PVC paths, and selectively use one of them.
An example of conventional PVC switching systems is disclosed in Japanese Patent Application Laid-Open No. 4-23648. The PVC switching system disclosed therein is to previously register a plural sets of combinations of connection pairs of PVC in a packet switching network. Then, one set is specified from the registered sets of connection pairs, allowing it to perform communication using the PVC registered in the specified set. When the specification of the set is changed, that is, when the PVC is changed over to another, all PVCs become once unavailable for communication.
A PVC switching system described in Japanese Patent Application Laid-Open No.8-181701 automatically selects the optimum intra-network connection path for PVC in an ATM switching network. That is, each of individual PVCs is monitored for its status, and the optimum path in the network is automatically selected when a failure or the like is detected to change over connection from one PVC to another.
In addition, a PVC switching system described in Japanese Patent Application Laid-Open No. 6-37809 causes one or more changed-over PVCs with priority to correspond to individual PVC logic channels in a packet switching network. In this way, it is possible to attain backup of computer services at multiple points. That is, when switching of PVC is instructed, it is to change over connection of PVC for the PVC logic channel for which switching is necessary for the specified priority. In other words, connection switching control is performed for the PVC logic channel under operation.
The conventional PVC switching system described in Japanese Patent Application Laid-Open No. 4-23648 allows only PVC registered for the selected connection set to perform communication. Thus, it has a disadvantage such that switching on PVC in only part of the network cannot be attained. In addition, even if the same PVC as that prior to switching exists after switching when PVC is switched, that PVC cannot be available for communication for a while.
A conventional PVC switching system described in Japanese Patent Application Laid-Open No. 8-181701 is to automatically select the optimum path in the network for individual PVCs. Therefore, there is a disadvantage that the administrator cannot switch parts or all of PVCs in a batch at his/her discretion.
Furthermore, a conventional PVC switching system described in Japanese Patent Application Laid-Open No. 6-37809 performs switching only for applicable PVCs among PVCs operating according to the specified priority under operation. Thus, there is a disadvantage that the administrator cannot necessarily change connection at his/her discretion.
Therefore, the PVC switching systems in the specifications described above have a disadvantage that, when parts or all of PVCs in the network are connected, disconnected, or changed for paths, the administrator cannot perform switching of them in batch and systematically at his/her discretion without affecting the communication state of PVCs not subject to switching control.
SUMMARY OF THE INVENTION
The present invention is made for overcoming the disadvantages of the prior art, and intended to provide a method and system for switching PVCs in which, when parts or all of PVCs in the ATM network are connected, disconnected, or changed for paths, the administrator can perform switching of them in batch and systematically at his/her discretion without affecting the communication state of PVCs not subject to switching control.
The PVC switching system according to the present invention is a PVC switching system for selectively using one of PVC information tables as a current table, and connecting an originating terminal and a terminating terminal according to content of the current table, each of the PVC information tables being recorded with originating and terminating correspondence information, the information containing information for identifying a originating terminal and a terminating terminal for each of those subject to switching of a plurality of PVCs, each of PVC being a connection path fixed with an originating terminal and a terminating terminal, wherein the system comprises comparison means,in response to a switching command for comparing content of each entry in the current table and those in a table used after switching, and connection control means for, when there are entries for which the result of the comparison fails to match, disconnecting the connection path indicated by the entries, and connecting a connection path indicated by the entries in the table used after switching.
In summary, the present invention compares contents of each entry in a table before and after switching, if there is an entry in which contents do not agree, disconnects a connection path indicated by the entry in a table currently used, and connects a connection path indicated by the entry in a table being used after switching. Since this performs no processing on the entries in which contents agree, the administrator can perform PVC switching on connection, disconnection and change of path for parts or all of PVCs in an ATM network in batch and systematically at his/her discretion without affecting communication state of PVCs for which switching connection is not required.
REFERENCES:
patent: 5029161 (1991-07-01), Nagashima
patent: 5067123 (1991-11-01), Hyodo et al.
patent: 5216669 (1993-06-01), Hofstetter et al.
patent: 5239537 (1993-08-01), Sakauchi
patent: 5267232 (1993-11-01), Katsube et al.
patent: 5271005 (1993-12-01), Takase et al.
patent: 59-186447 (1984-10-01), None
patent: 63-82143 (1988-04-01), None
patent: 3-230643 (1991-10-01), None
patent: 4-23648 (1992-01-01), None
patent: 6-37809 (1994-02-01), None
patent: 6-85830 (1994-03-01), None
patent: 8-181701 (1996-07-01), None
Chin Wellington
Duong Frank
NEC Corporation
Sughrue Mion Zinn Macpeak & Seas, PLLC
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