AAL terminal system of duplex configuration and synchronization method

• US 6,418,144 B1
• Filed: 04/15/1999
• Issued: 07/09/2002
• Est. Priority Date: 04/16/1998
• Status: Expired due to Fees

• Current Assignee: Juniper Networks Incorporated
• Original Assignee: NEC Corporation
• Inventors: Saeki, Shuichi
• Primary Examiner(s): Chin, Wellington
• Assistant Examiner(s): PHAM, BRENDA H
• Application Number:
  US09/292,566
• Time in Patent Office: 1,181 Days
• Field of Search: 370/219, 370/220, 370/395, 370/395.1, 370/395.6, 370/395.61, 370/395.63, 370/395.64, 370/395.65
• US Class Current: 370/395.6
• CPC Class Codes: H04L 12/5601 Transfer mode dependent, e.g. ATM
• CPC Class Codes: H04L 2012/5627 Fault tolerance and recovery
• CPC Class Codes: H04L 2012/5654 using the AAL1
• CPC Class Codes: H04L 2012/5674 Synchronisation, timing recovery or alignment

Abstract

A synchronization method in an AAL terminal system of a dual configuration including an acting ALL (ATM Adaptation Layer Type) terminal device and a standby ALL terminal device, for converting STM data to ATM cells, in which the acting ALL terminal device, upon receipt of a cell conversion starting request, starts cell conversion, notifies the starting timing of the cell conversion to the standby AAL terminal device, and starts counting input STM frame pulses by a frame pulse counter, while the standby ALL terminal device, upon receipt of the starting timing of the cell conversion, starts counting the input STM frame pulses by the frame pulse counter of the corresponding user connection, thereby establishing synchronization between output ATM cells of the acting device and output ATM cells of the standby device in each user connection by the frame pulse counter.

Claims

1. A synchronization method of an AAL terminal system of a duplex configuration comprising an acting AAL (ATM Adaptation Layer Type) terminal device and a standby AAL terminal device, for converting STM data into ATM cells, wherein

said acting AAL terminal device and said standby AAL terminal device comprise frame pulse counters with the predetermined count value set therein in every user connection of STM network;

in said acting AAL terminal device having received a cell conversion starting request,

starting cell conversion, notifying the starting timing of the cell conversion to said standby AAL terminal device, and starting count of input STM frame pulses by said frame pulse counter;

in the standby AAL terminal device having received the starting timing of the cell conversion,

starting count of the input STM frame pulses by said frame pulse counter of the corresponding user connection,

wherein establishing synchronization between output ATM cells of the acting device and output ATM cells of the standby device in each user connection by said frame pulse counter.

2. A synchronization method of an AAL terminal system of a dual configuration as set forth in claim 1, wherein

said acting AAL terminal device

continues to notify the timing to said standby AAL terminal device every time said frame pulse counter counts a predetermined count value until stopping the cell conversion.

3. A synchronization method of an AAL terminal system of a dual configuration as set forth in claim 1, wherein

said AAL terminal device is an AAL 1 (ATM Adaptation Layer Type 1) terminal device.

4. A synchronization method of an AAL terminal system of a dual configuration as set forth in claim 1, wherein

the predetermined count value set in said frame pulse counter corresponds to a speed of each user connection of the STM network.

5. A synchronization method of an AAL terminal system of a dual configuration as set forth in claim 1, wherein

said acting AAL terminal device

continues to notify the timing to said standby AAL terminal device every time said frame pulse counter counts the predetermined count value, until stopping the cell conversion;

while

said standby AAL terminal device

starts the cell conversion at the time when the count value of said frame pulse counter gets to the predetermined count value.

6. A terminal system of a dual configuration including an acting AAL terminal device and a standby AAL terminal device, the terminal system comprising converting means for converting STM data to ATM cells, control means, and a serial bus for connecting the both devices through the control means, wherein

said respective control means comprising

a plurality of frame pulse counters with predetermined count values set therein, in every user connection of the STM network;

said control means of said acting AAL terminal device comprising

means for directing said converting means to start cell conversion upon receipt of a cell conversion starting request,

means for directing said frame pulse counter to count input STM frame pulses at the same time of starting the cell conversion, and

means for notifying the starting timing of the cell conversion to said standby AAL terminal device through the serial bus;

while

said control means of said standby AAL terminal device comprising

means for directing said frame pulse counter of said standby device to start counting the input STM frame pulses, upon receipt of the timing, and

means for directing a start of cell conversion at the time when the count value of said frame pulse counter gets to the predetermined count value.

7. A terminal system of a dual configuration as set forth in claim 6, wherein

said acting control means

notifies the starting timing of the cell conversion to said standby AAL terminal device every time when said frame pulse counter counts the predetermined count value.

8. A terminal system of a dual configuration as set forth in claim 6, wherein

said AAL terminal device is an AAL 1 (ATM Adaptation Layer Type 1) terminal device.

9. A terminal system of a dual configuration as set forth in claim 6, wherein

the predetermined count value set in said frame pulse counter corresponds to the speed of each user connection of the STM network.