STM-to-ATM converters

• US 5,428,609 A
• Filed: 01/03/1994
• Issued: 06/27/1995
• Est. Priority Date: 01/03/1994
• Status: Expired due to Term

• Current Assignee: Nokia of America Corporation (Nokia Corporation)
• Original Assignee: AT&T Corporation (AT&T, Inc.)
• Inventors: Martin, Gary D., Eng, Kai Y., Spanke, Ronald A., Punj, Vikram, Pashan, Mark A.
• Primary Examiner(s): MARCELO, MELVIN C
• Application Number:
  US08/176,053
• Time in Patent Office: 540 Days
• Field of Search: 370/60, 370/60.1, 370/79, 370/82, 370/84, 370/94.1, 370/94.2, 370/99, 370/100.1, 370/105.1
• US Class Current: 370/392
• CPC Class Codes: H04J 2203/0089 Multiplexing, e.g. coding, scrambling, SONET
• CPC Class Codes: H04J 3/0632 Synchronisation of packets and cells, e.g. transmission of voice via a packet network, circuit emulation service [CES] queuing arrangements in packet switching elements H04L49/90; synchronising systems for the synchronous transmission of a pulse code modulated video signal with one or more other pulse code modulated signals H04N7/56
• CPC Class Codes: H04L 2012/5652 Cell construction, e.g. including header, packetisation, depacketisation, assembly, reassembly
• CPC Class Codes: H04L 2012/5672 Multiplexing, e.g. coding, scrambling
• CPC Class Codes: H04Q 11/0478 Provisions for broadband connections

Abstract

A data stream is converted from a synchronous transfer mode (STM) to an asynchronous transfer mode (ATM) by extracting data of a number of payload signals from the data stream, writing data of the payload signal into a random access memory (RAM), separately recording address locations of the data of each of the payload signals in separate buffers, directing the RAM to separately read the data of the payload signals, and attaching a cell header to the data read from the RAM to form ATM cells.

Claims

1. The method of processing a data stream in a synchronous transfer mode (STM) comprising:

extracting a plurality of payload signals having data from the data stream;

writing data of the payload signals into a random access memory (RAM);

separately recording address locations of the data of each of the plurality of payload signals;

directing the RAM to separately read the data of each single one of the payload signals; and

attaching a cell header to the data read from the controller to form ATM cells.

2. A method as in claim 1, wherein the extracting step includes removing overhead in the synchronous digital hierarchy framing.

3. A method as in claim 1, wherein the recording step includes recording in a separate buffer for each of said payload signals.

4. A method as in claim 1, wherein the recording step includes recording in a separate first-in-first-out buffer for each of the payload signals.

5. A system for processing a data stream in a synchronous transfer mode (STM) comprising:

means for extracting a plurality of payload signals from the data stream;

a random access memory (RAM);

means for writing data of the payload signals into said random access memory (RAM);

buffer means for recording RAM locations of the data of the payload signal;

programmable controller means for directing said RAM to read the data of each single one of the payload signals; and

said programmable controller means including means for attaching a cell header to the data read to form an ATM cell.

6. A system as in claim 5, wherein the data stream includes synchronous digital hierarchy framing and said extracting means includes means for removing overhead in the synchronous data hierarchy framing.

7. A system as in claim 5, wherein the recording means includes a separate buffer for each of the payload signals.

8. A system as in claim 5, wherein the recording means includes a separate first-in-first-out buffer for the payload signal.