Virtual connection switching method and ATM switch

• US 6,822,962 B1
• Filed: 11/28/2000
• Issued: 11/23/2004
• Est. Priority Date: 11/29/1999
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi Telecom Technologies Limited
• Inventors: Ohwada, Katsuya, Noake, Toshimichi, Ichikawa, Toshiki, Ando, Sadato, Mori, Mitsumasa
• Primary Examiner(s): Pezzlo, John
• Assistant Examiner(s): Mills, Donald L
• Application Number:
  US09/722,411
• Time in Patent Office: 1,456 Days
• Field of Search: 370/217, 370/218, 370/219, 370/220, 370/221, 370/225, 370/228, 370/395.2, 370/395.3, 370/241.1, 370/236.1, 370/236.2, 370/242, 370/244, 370/248, 370/250
• US Class Current: 370/395.2
• CPC Class Codes: H04L 5/14 Two-way operation using the same type of signal, i.e. duplex
• CPC Class Codes: H04L 5/20 using different combinations of lines, e.g. phantom working

Abstract

A communication network capable of establishing an SVC bypass route when a failure occurs in a PVC multiplexed line wherein each of ATM switches at both ends of a PVC stores the relations of SVC specifying information and the other party PVC information in association with each PVC in a management table. At the time of bypassing, one of the switches transmits a message including the other party PVC information to another ATM switch for each PVC to be bypassed and another ATM switch specifies a PVC to be switched on the basis of the received message and switches the PVC to an SVC specified by the corresponding SVC specifying information stored in the management table.

Claims

1. A method of switching a virtual connection between first and second ATM switches in an ATM network, comprising the steps of:

previously storing into said first ATM switch, before a PVC between the first and second ATM switches is in a failure state, first bypassing control information in association with first PVC management information specifying the PVC, the first bypassing control information indicating first SVC specifying information for specifying an SVC to be used as a bypass of the PVC, address information of said second ATM switch, and second PVC specifying information necessary for said second ATM switch to specify the PVC;

previously storing into said second ATM switch before the PVC between the first and second ATM switches is in a failure state, second bypassing control information in association with second PVC management information specifying the PVC, the second bypassing control information indicating second SVC specifying information for specifying an SVC to be used as a bypass of the PVC, address information of said first ATM switch, and first PVC specifying information necessary for said first ATM switch to specify the PVC;

transmitting a bypassing call setup message autonomously from said first ATM switch to a line specified by the first SVC specifying information at the time of an operation of switching the PVC to the SVC, the bypassing call setup message including said second PVC specifying information and being transmitted using the address information of the second ATM switch as a called party address;

switching the PVC to the SVC by said first ATM switch on the basis of the first PVC management information and said first SVC specifying information when a response is received from said second ATM switch; and

referring to the second bypassing control information corresponding to said second PVC specifying information extracted from the bypassing call setup message by said second ATM switch, thereby to switch a PVC specified by the second PVC specifying information to an SVC specified by the second SVC specifying information included as a part of the second bypassing control information.

2. A method of switching a virtual connection in an ATM communication network having a plurality of ATM switches, comprising the steps of:

previously storing into each of said plurality of ATM switches, bypassing control information in association with PVC management information for each of PVCs multiplexed on a physical or logical line, each of the bypassing control information indicating SVC specifying information for specifying an SVC to be used as a bypass of the PVC, address information of a counterpart ATM switch located at the other end of the PVC, and the other side PVC specifying information necessary for the counterpart ATM switch to specify the PVC to be bypassed;

transmitting when a bypassing factor occurs in a specific physical or logical line, a bypassing call setup message autonomously from one of said plurality of ATM switches which is using the physical or logical line, to a line specified by the stored SVC specifying information for each of the PVCs multiplexed on the physical or logical line, the bypassing call setup message including said the other side PVC specifying information and being transmitted using the address information of the counterpart ATM switch as a called party address;

switching the PVC to an SVC by said one of plurality of the ATM switches, on the basis of the stored PVC management information and said stored SVC specifying information when a response is received from said counterpart ATM switch; and

referring, by said counterpart ATM switch, to bypassing control information corresponding to said the other side PVC information extracted from the received bypassing call setup message, thereby to switch a PVC specified by said the other side PVC specifying information to an SVC specified by the SVC specifying information included as a part of the referred bypassing control information.

3. An ATM switch having a function of switching a PVC to an SVC, comprising:

a memory for storing bypassing control information blocks in association with PVC management information blocks prepared for each of PVCs of the ATM switch, each of said PVC management information blocks indicating PVC specifying information for specifying one of said PVCs, and each of said bypassing control information blocks indicating SVC specifying information for specifying an SVC to be used as a bypass of corresponding one of said PVCs, address information of a counterpart ATM switch at the other end of the PVC, and the other side PVC specifying information necessary for the counterpart ATM switch to specify the PVC to be bypassed;

first means for transmitting when a bypassing factor of switching a specific PVC to an SVC occurs, a bypassing call setup message autonomously to a line specified by the SVC specifying information of one of said bypassing control information blocks which is in association with the PVC management information block corresponding to the specific PVC and switching the specific PVC to the SVC on the basis of the PVC specifying information and the SVC specifying information, the bypassing call setup message including the other side PVC specifying information indicated by the one of said bypassing control information blocks and being transmitted using the address information of the counterpart ATM switch as a called party address; and

second means for referring when a bypassing call setup message is received from one of the other ATM switches, to the bypassing control information block corresponding to the other side PVC specifying information extracted from the bypassing call setup message and switching a PVC specified by said the other side PVC specifying information to an SVC specified by the SVC specifying information indicated by the bypassing control information block which is in association with the PVC management information block specified by said the other side PVC specifying information.

4. An ATM switch according to claim 3, wherein said first means comprises means for specifying a group of PVCs multiplexed on a specific physical or logical line to be bypassed by referring to the PVC management information blocks in said memory, thereby to transmit said bypassing call setup message to the counterpart ATM switch on the PVC and to switch the PVC to an SVC, for each of the PVCs.

5. An ATM switch according to claim 3, wherein

said first means comprises means for storing a call reference given to the bypassing call setup message into the PVC management information block and means for transmitting a bypassing call release message having the call reference read out from the PVC management information block to the same line, to which the bypassing call setup message has been sent out, by using address information of the counterpart ATM switch as a called party address at the time of switching the SVC as a bypass back to the original PVC, and

said second means comprises means for storing a call reference extracted from the bypassing call setup message received from said one of the other ATM switches into one of said PVC management information blocks corresponding to said the other side PVC specifying information extracted from the received bypassing call setup message and means for retrieving a PVC management information block having the call reference of the received bypassing call setup message and recovering when said bypassing call release message is received a PVC specified by said PVC specifying information indicated by the PVC management information block retrieved.

6. An ATM switch according to claim 4, wherein

said first means comprises means for storing a call reference given to the bypassing call setup message into the PVC management information block and means for transmitting a bypassing call release message having the call reference read out from the PVC management information block to the same line, to which the bypassing call setup message has been sent out, by using address information of the counterpart ATM switch as a called party address at the time of switching the SVC as a bypass back to the original PVC, and

said second means comprises means for storing a call reference extracted from the bypassing call setup message received from said one of the other ATM switches into one of said PVC management information blocks corresponding to said the other side PVC specifying information extracted from the received bypassing call setup message and means for retrieving a PVC management information block having the call reference of the received bypassing call setup message and recovering when said bypassing call release message is received a PVC specified by said PVC specifying information indicated by the PVC management information block retrieved.

7. An ATM switch according to claim 3, wherein

said first means comprises means for storing reference information related to a call reference given to the bypassing call setup message into the PVC management information block and means for transmitting a bypassing call release message having the call reference to the same line, to which the bypassing call setup message has been sent out, by using address information of the ATM counterpart ATM switch as a called party address at the time of switching the SVC as a bypass back to the original PVC, and

said second means comprises means for storing reference information specified from to the call reference extracted from the bypassing call setup message received from said one of the other ATM switches into one of said PVC management information blocks corresponding to said the other side PVC specifying information extracted from the received bypassing call setup message and means for retrieving when said bypassing call release message is received a PVC management information block having the reference information corresponding to the call reference of the received message and recovering a PVC specified by said PVC specifying information indicated by the PVC management information block retrieved.

8. An ATM switch according to claim 4, wherein

said first means comprises means for storing reference information related to a call reference given to the bypassing call setup message into the PVC management information block and means for transmitting a bypassing call release message having the call reference to the same line, to which the bypassing call setup message has been sent out, by using address information of the ATM counterpart ATM switch as a called party address at the time of switching the SVC as a bypass back to the original PVC, and

said second means comprises means for storing reference information specified from to the call reference extracted from the bypassing call setup message received from said one of the other ATM switches into one of said PVC management information blocks corresponding to said the other side PVC specifying information extracted from the received bypassing call setup message and means for retrieving when said bypassing call release message is received from a PVC management information block having the reference information corresponding to the call reference of the received message and recovering a PVC specified by said PVC specifying information indicated by the PVC management information block retrieved.