Multiplex communications – Fault recovery – Bypass an inoperative switch or inoperative element of a...
Reexamination Certificate
2001-11-26
2004-08-24
Marcelo, Melvin (Department: 2663)
Multiplex communications
Fault recovery
Bypass an inoperative switch or inoperative element of a...
C370S395200, C370S395300
Reexamination Certificate
active
06781952
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an ATM switching apparatus and a route setting system in an ATM switching apparatus network having the same. More particularly, the present invention relates to a system for setting S-PVC (Soft-Private Virtual Connection).
2. Description of the Related Art
When a network is operated by a plurality of ATM switching apparatuses, a PVC technique is known as a connection establishing scheme reflecting the intention of an operation administrator in the network. When the network is operated by using the ATM switching apparatuses of an identical vendor, a substitution route which is previously designated by a precut reroute function is used when a fault has occurred. Therefore, the securing of the route can be continued. However, when a network is operated by using the ATM switching apparatuses of a plurality of vendors, the route sometimes cannot be secured because the above function cannot be applied. For such a case, the system to which PNNI (Private Network-Network Interface) operation is applied is known in order to establish a substitution route in case of the fault in the network containing the ATM switching apparatuses of the plurality of vendors for making the network available continuously. In this system, the substitution route can be secured by a connection retry function in the case of the fault using the S-PVC scheme under the PNNI operation network.
However, in the conventional example, it is not possible to designate an optional route in accordance with an instruction of the operation administrator when a connection is established based on the S-PVC scheme under the PNNI operation in which a substitution route is considered. This is because a route is automatically selected based on a route calculation result which has been already obtained in an originated node in the route in issuance of a S-PVC connection establishing instruction in the PNNI network. In this way, when a S-PVC connection is established on the PNNI network, an optimal route is automatically determined using PNNI topology data of the originated node in the route by specifying a destination node. These conventional examples are described in “Private Network-Network Interface Specification Version 1.0”, (The ATM Forum af-pnni-0055.000, March 1996).
In conjunction with the above description, a system and method for switching a route in case of occurrence of a fault of the ATM switching apparatus is described in Japanese Laid Open Patent Application (JP-A-Heisei 11-355310). In this reference, a substitution route is previously set for a present route between an origination switch and a termination switch. In this case, a band is not secured for the substitution route, and route data is managed. When a fault has occurred on the present route or in a relay switch, the route is switched from the present route to the substitution route and the band is secured. A fault condition on the present route and the substitution route is monitored and a remaining band of the substitution route is monitored. Based on the monitoring result, the route data is updated in the origination switch.
Also, a rerouting method of PVC in an ATM network and a network managing system is disclosed in Japanese Laid Open Patent Application (JP-P2000-59374A). In this reference, a substitution route is previously defined for PVC managed on the network managing system. The substitution route is used when a fault has occurred.
Also, a communication network fault recovering system is disclosed in Japanese Patent No. 2933021. In this reference, a network management system controls a transmission unit through a control line. When a fault has occurred, the network management system releases a band of a path which passes through a fault occurrence portion. Then, the network management system determines a substitution route based on fault recovery classes set for the respective paths.
A method of setting a PVC (permanent virtual circuit) is disclosed in Japanese Laid Open Patent Application (JP-A-Showa 63-82145). In this reference, a PVC is registered or released between packet switching apparatuses of a current use system and a substitution system. For this purpose, data necessary for setting the PVC is inputted from an operator console to a packet switching apparatus connected thereto and is temporality stored therein. A counter packet switching apparatus is determined based on the stored data and a notice packet is produced to have data necessary for the counter packet switching apparatus to set the PVC and is transmitted to the counter packet switching apparatus. The temporality stored data is registered on a retry process registering table in the packet switching apparatus when a reply packet to the notice packet is not received for a predetermined time from the counter packet switching apparatus or when the reply packet indicates a fault end. The retry process registering table is referred to for every time period, and the notice packet is produced again for the data registered on the retry process registering table and is retransmitted to the counter packet switching apparatus. The data registered on the retry process registering table is invalidated when the response packet indicates a normal end, and a retry count of the data registered on the retry process registering table is incremented by one, otherwise. When the retry count exceeds a predetermined value, the fault of the PVC setting is notified from the packet switching apparatus to the operator console.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a system in which the connection of an optional route designated by an operation administrator can be established, and the continuation use of a route is guaranteed by a substitution route establishing function by using S-PVC on a PNNI network composed of a plurality of ATM switching apparatuses of vendors, even when a fault has occurred.
In an aspect of the present invention, a method of establishing an S-PVC (soft private virtual connection) connection in a PNNI (private network-network interface) network of a plurality of peer groups, each of which includes at least an ATM (asynchronous transfer mode) switching apparatus as an ATM node, is attained by (a) setting a first identifier and first designated route data associated with the S-PVC channel in each of the plurality of peer groups; by (b) in the ATM node in each of the plurality of peer groups, receiving a call originating request including second designated route data and a second identifier; by (c) comparing the first identifier and the second identifier; by (d) generating a next call originating request containing third designated route data as the second designated route data and the second identifier for a next node based on the first and second designated route data and the second identifier when the first identifier and the second identifier are coincident with each other; by (e) transmitting the next call originating request to the next node; and by (f) repeating the steps (b) to (e) over each of the plurality of peer groups.
Here, the first designated route data may be designated optionally.
Also, each of the first and second identifiers may be an NCCI (network call correlation identifier), or may contain at least one of a destination number CdPN: called party number) and a source number (CgPN: calling party number).
Also, when the one peer group includes the ATM node, the step (a) may includes the steps of (g) determining based on the first designated route data, whether establishment of the S-PVC connection is possible; and (h) setting the first designated route data and the first identifier when it is determined that the establishment of the S-PVC connection is possible. In this case, the first designated route data and the first identifier may be discarded when it is determined that establishment of the S-PVC connection is not possible.
In this case, also, in the step (g), whether the establishment of the S-PVC connection is possible may be determined b
Marcelo Melvin
NEC Corporation
Whitham Curtis & Christofferson, PC
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