Mechanism for multiplexing ATM AAL5 virtual circuits over ethernet

• US 5,946,313 A
• Filed: 03/20/1997
• Issued: 08/31/1999
• Est. Priority Date: 03/20/1997
• Status: Expired due to Term

• Current Assignee: RPX Clearinghouse LLC (RPX Corporation)
• Original Assignee: Northern Telecom Limited (Nortel Networks Corporation)
• Inventors: Robert, Andre J., Casey, Liam M., Allan, David Ian
• Primary Examiner(s): Pham, Chi H.
• Assistant Examiner(s): Tran, Maikhanh
• Application Number:
  US08/821,145
• Time in Patent Office: 894 Days
• Field of Search: 370/397, 370/395, 370/398, 370/401, 370/471, 370/473, 370/474
• US Class Current: 370/397
• CPC Class Codes: H04L 12/4633 Interconnection of networks using encapsulation techniques, e.g. tunneling
• CPC Class Codes: H04L 12/64 Hybrid switching systems
• CPC Class Codes: H04L 2012/5618 Bridges, gateways [GW] or interworking units [IWU]
• CPC Class Codes: H04L 2012/5658 using the AAL5
• CPC Class Codes: H04L 2012/5665 Interaction of ATM with other protocols
• CPC Class Codes: H04Q 11/0478 Provisions for broadband connections

Abstract

The invention provides for a E-Mux and a method for encapsulating/segmenting ATM cells into/from an Ethernet frame at the boundary between an ATM and an Ethernet network. An Ethernet end-station on the E-Mux is addressed using multiple MAC level identifiers, which are dynamically assigned according to the ATM virtual circuits which terminate on that end station, and have only transitory significance on the Ethernet. A unique ATM OUI identifies the frames carrying ATM-traffic.

Claims

1. A multiplexer (E-Mux) for encapsulating ATM cells into a LAN frame, comprising:

a segmentation and reassembly unit for receiving a plurality of incoming ATM cells with a LAN destination address, and generating an ATM adaptation layer 5 (AAL5) protocol data unit (PDU);

a PDU manager for receiving said AAL5 PDU and extracting an AAL5 payload;

a header processor for extracting a traffic type indicator from the header of said PDU;

an address processor for extracting said LAN destination address from the header of an incoming ATM cell; and

a frame manager for receiving said traffic type indicator, said AAL5 payload and said LAN destination address and generating an incoming LAN frame.

2. A multiplexer as claimed in claim 1, wherein said LAN is an Ethernet network and said incoming LAN frame is an Ethernet frame.

5. A multiplexer as claimed in claim 2, further comprising:

an E-Mux-to-Ethernet interface for formatting said Ethernet frame for transmission over the connection medium of an Ethernet network; and

an ATM-to-E-Mux interface for formatting said ATM cells received from an ATM network for processing by said E-Mux.

3. A multiplexer (E-Mux) for segmenting a LAN frame into a plurality of ATM cells, comprising:

a frame manager for receiving an outgoing LAN frame with an ATM destination address and de-assembling it into a traffic type indicator, an AAL5 payload and an ATM destination address;

a header processor for receiving said traffic type indicator from said frame manager;

a PDU manager for receiving said AAL5 payload and said traffic type indicator and generating an ATM adaptation layer 5 (AAL5) protocol data unit (PDU);

an address processor for receiving said ATM destination address from said frame manager; and

a segmentation and reassembly unit for receiving said PDU and said ATM destination address generating a plurality of ATM cells with said ATM destination address.

4. A multiplexer as claimed in claim 3, wherein said LAN is an Ethernet network and said outgoing LAN frame is an Ethernet frame.

6. A multiplexer as claimed in claim 4, further comprising:

an E-Mux-to-ATM interface for formatting said ATM cells for transmission over the medium of an ATM network; and

an Ethernet-to-E-Mux interface for formatting said Ethernet frame received over a transmission medium of an Ethernet network for processing by said E-Mux.

7. An Ethernet network comprising a plurality of end stations and an Ethernet/ATM interface connected over a transmission medium, each end station comprising an address controller for forwarding an incoming LAN frame received from said Ethernet/ATM interface ATM network to said end station when a destination address comprised in the destination MAC field of said frame is recognized by said address controller, and for inserting an ATM destination address into the source MAC field of an outgoing frame destined to said Ethernet/ATM interface.

8. A telecommunication network comprising a LAN with a plurality of end-stations connected over a transmission medium and an ATM network, comprising:

a multiplexer (E-Mux) for encapsulating a plurality of incoming ATM cells received from said ATM network into an incoming LAN frame and for segmenting an outgoing LAN frame received from said LAN network into a plurality of outgoing ATM cells;

an E-Mux-to-LAN interface for formatting said incoming LAN frame for transmission over the connection medium of said LAN network, and for formatting said outgoing Ethernet frame received over the connection medium of said LAN network for processing by said E-Mux;

an ATM-to-E-Mux interface for formatting of said incoming ATM cells received from said ATM network for processing by said E-Mux, and for formatting said outgoing cells for transmission over the medium of said Ethernet network; and

an address controller at each end station for forwarding said incoming LAN frame to said end station when a destination address comprised in the destination MAC field of said incoming LAN frame is recognized by said address controller, and for inserting an ATM destination address into the source MAC field of said outgoing LAN frame, when said outgoing LAN frame is destined to said ATM network.

9. A method for transmitting information from an ATM network to an Ethernet network using an E-Mux performing the steps of:

establishing connection between an ATM switch of said ATM network and an end station of said Ethernet network based on a VPI/VCI destination address in the header of an incoming ATM cell;

receiving a plurality of incoming ATM cells with said destination address, and generating an ATM adaptation layer 5 (AAL5) protocol data unit (PDU);

extracting an AAL5 payload from said PDU;

extracting a traffic type indicator from the header of said PDU;

generating an incoming Ethernet frame using said traffic type indicator, said AAL5 payload and said destination address; and

transmitting said Ethernet frame over said Ethernet network to said end station according to said destination address.

10. A method as claimed in claim 9, wherein said incoming Ethernet frame comprises:

a destination MAC field including;

a unique ATM OUI identifier indicating that said incoming Ethernet frame comprises ATM traffic; and

said VPI/VCI destination address specifying the address of said end station;

a source MAC field including;

said ATM OUI identifier indicating that said incoming Ethernet frame comprises ATM traffic; and

a unique address of said E-Mux.

11. A method for transmitting information from an Ethernet network to an ATM network using an E-Mux performing the steps of:

establishing connection between an end station of said Ethernet network and an ATM switch of said ATM network based on a VPI/VCI destination address provided by said end station;

generating an outgoing Ethernet frame at said end station and transmitting said frame to said E-Mux;

extracting from said Ethernet outgoing frame a traffic type indicator, a frame payload and a source address;

generating an ATM adaptation layer 5 (AAL5) protocol data unit (PDU) from said frame payload and a traffic type indicator extracted from the type field of said outgoing frame; and

segmenting said PDU into a plurality of outgoing ATM cells and inserting a VPI/VCI destination address in the header of said cells from an address processor.

12. A method as claimed in claim 11, wherein said outgoing Ethernet frame comprises:

a destination MAC field including;

a unique ATM OUI identifier indicating that said outgoing Ethernet frame comprises ATM traffic; and

a unique address of said E-Mux;

a source MAC field including;

said ATM OUI identifier indicating that said outgoing Ethernet frame comprises ATM traffic; and

said VPI/VCI destination address specifying the address of said ATM cell.