Multiplex communications – Pathfinding or routing – Combined circuit switching and packet switching
Reexamination Certificate
1999-12-01
2004-08-17
Kizou, Hassan (Department: 2662)
Multiplex communications
Pathfinding or routing
Combined circuit switching and packet switching
C370S395500
Reexamination Certificate
active
06778529
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
This invention relates generally to the field of telecommunications, and more particularly to a synchronous switch and method for a telecommunications node.
BACKGROUND OF THE INVENTION
The Internet has dramatically increased the potential for data, voice, and video services for customers. Existing circuit-switched telephony systems, however, do not provide the foundation to support the growing need for bandwidth and new services required by both residential and business consumers. As a result, integrated access devices have been introduced to support Internet and related technologies as well as standard telephony service for customers.
Integrated access devices often combine synchronous and asynchronous transport and switch functionality to multiplex data, voice, and video traffic together onto a single network. Within an integrated access device, a time division multiplex (TDM) bus is typically used to transport voice and other synchronous traffic between the line cards and a switch core. An asynchronous transfer mode (ATM) bus is used to transport ATM traffic between the line cards and the switch core.
At the switch core, ATM traffic normally arrives asynchronously while TDM traffic arrives in a regular and periodic fashion. Separate ATM and TDM switch hardware are provided at the switch core to receive and process the ATM and TDM traffic, respectively. TDM traffic may be segmented to and reassembled from the ATM format using ATM adaption layer (AAL) standards for high-speed transmission on the network and for distribution to customer premises after transmission over the network. The separate data paths and switching hardware for ATM and TDM traffic is expensive and may be cost prohibitive for some lower rate applications.
SUMMARY OF THE INVENTION
The present invention provides a synchronous switch and a method for a telecommunications node that substantially reduces or eliminates the disadvantages and problems associated with previous systems and methods. In particular, the synchronous switch uses a common data path and memory to switch both asynchronous transfer mode (ATM) and time division multiplex (TDM) traffic. As a result, switching hardware is reduced and line cards communicating with the synchronous switch may include a mix of both ATM and TDM traffic.
In accordance with one embodiment of the present invention, a synchronous switch for a telecommunications node includes a switch interface operable to terminate a bus and to receive from the bus a frame having a plurality of time slots. The time slots are each operable to transport a traffic cell. A switch controller is operable to determine a type for each traffic cell received at the switch interface and to determine based on the type for a traffic cell an address for storing the traffic cell in a switch memory. The switch memory is operable to receive the traffic cell from the switch interface and the address for storing the traffic cell from the switch controller and to store the traffic cell at the address.
More particularly, in accordance with a particular embodiment of the present invention, the switch memory includes a plurality of TDM memory slots in a plurality of ATM queues associated with output ports. In this and other embodiments, the switch interface is operable to extract a header for the traffic cell from a time slot transporting the traffic cell and to provide the header to the switch controller. The switch controller is operable to determine an address of an ATM queue in the switch memory for storing the traffic cell in response to determining from the header that the traffic cell is of an ATM type and to determine an address in a TDM memory slot in the switch memory for storing the traffic cell in response to determining from the header that the traffic cell is of a TDM type.
Technical advantages of the present invention include providing an improved switch for a telecommunications node. In particular, the switch receives both ATM and TDM traffic cells in time slots and utilizes a common data path and memory to perform cell switching. For TDM cells, the switch data path is configured to route the cell into a TDM memory slot that is accessed in a TDM manner. For ATM cells, the switch data path is configured to route the cells to queues associated with output ports for the cells. The dual functionality of the switch data path reduces switching hardware in the switch core. As a result, the cost of the switch core and the network element are reduced.
Another technical advantage of the present invention includes providing a synchronous cell-based switch for a telecommunications node. In particular, the switch operates synchronously at a defined frame pulse to switch ATM and TDM traffic cells. As a result, ATM adaption layer (AAL) cells transporting TDM traffic are switched synchronously at the cell level.
Other technical advantages of the present invention will be readily apparent to one skilled in the art from the following figures, description, and claims.
REFERENCES:
patent: 4862451 (1989-08-01), Closs et al.
patent: 5327428 (1994-07-01), Van As et al.
patent: 5570362 (1996-10-01), Nishimura
patent: 5577039 (1996-11-01), Won et al.
patent: 5604742 (1997-02-01), Colmant et al.
patent: 5615211 (1997-03-01), Santore et al.
patent: 5734653 (1998-03-01), Hiraiwa et al.
patent: 5841771 (1998-11-01), Irwin et al.
patent: 5848067 (1998-12-01), Osawa et al.
patent: 5943339 (1999-08-01), Mauger
patent: 5953330 (1999-09-01), Canniff et al.
patent: 6005865 (1999-12-01), Lewis et al.
patent: 6167062 (2000-12-01), Hershey et al.
patent: 6243382 (2001-06-01), O'Neill et al.
patent: 6310891 (2001-10-01), Dove et al.
patent: 6320877 (2001-11-01), Humphrey et al.
patent: 6400713 (2002-06-01), Thomas et al.
patent: 6404782 (2002-06-01), Berenbaum et al.
patent: 6442167 (2002-08-01), Aramaki et al.
patent: 2002/0181484 (2002-12-01), Aimoto
ITU-T Recommendation I.363, “B-ISDN ATM Adaptation Layer (AAL) Specification,” Mar. 1993, 100 pages.
Bellcore GR-253-CORE, “Synchronous Optical Network (SONET) Transport Systems: Common Generic Criteria,” Issue 2, Dec. 1995 (with rev. Jan. 1999), 788 pages.
ATM Forum, “Circuit Emulation Service Interoperability Specification,” Version 2.0, Jan. 1997, AF-VTOA-0078.000, 101 pages.
ATM Forum, “Specifications of (DBCES) Dynamic Bandwidth Utilization—in 64Kbps Time Slot Trunking over ATM—Using CES,” Jul. 1997, AF-VTOA-0085.000, 32 pages.
Bellcore GR-2837, “ATM Virtual Path Ring Functionality in SONET—Generic Criteria,” Feb. 1998, 154 pages.
Power PC, POWERQUICC™, MPC860 User's Manual Motorola, © 1996, 1, 143 pages, Jul. 1998.
International Telecommunication Union, Series I: Integrated Servicdes Digital Network, “B-ISDN operation and maintenance principles and functions,” Feb. 1999, 116 pages.
“About ATM” www.atmforum.com/atmforum/library
otes1, 2, 3, 4 and 5 printed Aug. 30, 1999, 5 pages.
U.S. patent application Ser. No. 09/390,420, entitled “Method and System for Transmitting Traffic Having Disparate Rate Components,” filed Sep. 3, 1999, 30 pages. (0368).
U.S. patent application Ser. No. 09/419,204, entitled “Method and System for Distributed Processing of Traffic in a Telecommunications Node,” filed Oct. 15, 1999, 37 pages. (0369).
U.S. patent application Ser. No. 09/607,771, entitled “Method and System for Protection Switching in a Telecommunications Network,” Jun. 30, 2000, 32 pages. (0388).
U.S. patent application Ser. No. 09/628,532, entitled “Method and System for Reprogramming Instructions for a Switch,” filed Jul. 31, 2000, 35 pages. (0370).
U.S. patent application Ser. No. 09/657,068, entitled “Method and System for Processing Traffic in an Access Network,” filed Sep. 7, 2000, 41 pages. (0362).
“Asynchronous Transfer Mode (ATM) Switching,” printed from www.cisco.com on Aug. 27, 2002, 19 pages.
Buckland Kenneth M.
Dorbolo Riccardo G.
Field Barry W.
Baker & Botts L.L.P.
Cisco Technology Inc.
Kizou Hassan
Swickhamer Christopher M.
LandOfFree
Synchronous switch and method for a telecommunications node does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Synchronous switch and method for a telecommunications node, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Synchronous switch and method for a telecommunications node will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3355091