Universal transfer method and network with distributed switch

• US 6,356,546 B1
• Filed: 08/11/1998
• Issued: 03/12/2002
• Est. Priority Date: 08/11/1998
• Status: Expired due to Term

• Current Assignee: Ciena Corporation
• Original Assignee: Nortel Networks Limited (Nortel Networks Corporation)
• Inventors: Beshai, Maged E.
• Primary Examiner(s): Yao, Kwang B.
• Assistant Examiner(s): Pham, Brenda H.
• Application Number:
  US09/132,465
• Time in Patent Office: 1,309 Days
• Field of Search: 359/125, 359/139, 370/235, 370/312, 370/329, 370/341, 370/349, 370/352, 370/354, 370/360, 370/389, 370/399, 370/400, 370/409, 370/437, 370/396, 370/392
• US Class Current: 370/358
• CPC Class Codes: H04L 45/302 Route determination based on requested QoS
• CPC Class Codes: H04L 49/10 characterised by the switching fabric construction
• CPC Class Codes: H04L 49/111 Switch interfaces, e.g. port details
• CPC Class Codes: H04L 49/205 Quality of Service based
• CPC Class Codes: H04L 49/25 Routing or path finding in a switch fabric
• CPC Class Codes: H04L 49/253 using establishment or release of connections between ports
• CPC Class Codes: H04L 49/30 Peripheral units, e.g. input or output ports
• CPC Class Codes: H04L 69/22 Parsing or analysis of headers

Abstract

A method and a network for a universal transfer mode (UTM) of transferring data packets at a regulated bit rate are disclosed. The method defines a protocol that uses an adaptive packet header to simplify packet routing and increase transfer speed. The protocol supports a plurality of data formats, such as PCM voice data, IP packets, ATM cells, frame relay and the like. The network preferably includes a plurality of modules that provide interfaces to various data sources. The modules are interconnected by an optic core with adequate inter-module links with preferably no more than two hops being required between any origination/destination pair of modules. The adaptive packet header is used for both signaling and payload transfer. The header is parsed using an algorithm to determine its function. Rate regulation is accomplished using each module control element and egress port controllers to regulate packet transfer. The protocol enables the modules to behave as a single distributed switch capable of multi-terabit transfer rates. The advantage is a high speed distributed switch capable of serving as a transfer backbone for substantially any telecommunications service.

Claims

1. A Universal-Transfer-Mode network (UTM network), comprising a plurality of Universal-Transfer-Mode modules (UTM modules) interconnected by a passive core, said passive core consisting of a plurality of optical cross connectors through which routes are established among said UTM modules, wherein each of said UTM modules includes a plurality of ports that accept data in Universal-Transfer-Mode format (UTM ports) and optionally includes other ports selected from a group comprising:

(a) STM ports;

(b) ATM ports;

(c) Frame relay ports; and

(d) IP ports; and

wherein each of said UTM ports is operable to process UTM packets according to a Universal-Transfer-Mode protocol (UTM protocol), and each of said UTM ports includes

(a) a hysteresis control circuit operable to determine data transfer allocations; and

(b) a scheduler of data packets of variable sizes said scheduler operable to control the rate of data transfer at the egress of each UTM port.

2. The UTM network of claim 1 wherein said UTM packets include control UTM packets and payload UTM packets, and wherein each of said control UTM packets performs any of the functions of setting up and tearing down a path, setting-up and tearing down a connection within a path, and setting-up and tearing down an independent connection.

3. A UTM network as claimed in claim 2 wherein an originating UTM module for a data communications session receives data packets from a plurality of sources, creates a UTM header for each of said data packets and appends one of said data packets to each UTM header to enable the of transfer of the respective data packets through the UTM network.

4. The UTM network of claim 2 wherein said UTM packets are received from UTM data sources and other UTM modules.

5. The UTM network of claim 4 wherein said UTM data sources are virtual private corporate networks that exchange data using the UTM protocol.

6. The UTM network of claim 2 wherein said payload UTM packets are transferred in a rate-regulated stream and the regulated rate of transfer for said stream is applied at each UTM module in a route from a source to a sink.

7. The UTM network of claim 6 wherein said rate regulated stream includes any of a path, a connection within a path, and an independent connection.

8. A UTM network as claimed in claim 7 comprising a number N of UTM modules, said number N exceeding two, wherein a set of routes from any UTM module to any other UTM module includes a direct route and (N−

2) two-hop routes and the number of routes to be considered in setting up a connection is a function of a requested class of service and a requested bit rate for the connection.

9. The UTM network of claim 8 wherein said payload UTM packets belong to connectionless traffic streams and a provisional connection is established for each of said connectionless traffic streams.

10. The UTM network of claim 8 wherein said UTM header is parsed by each UTM module traversed by the data packets to determine a function and a route for forwarding the packet through the UTM network.

11. The UTM network of claim 10 further embedding a plurality of virtual private networks, each of said virtual private networks being formed as a number of paths with regulated capacities and a number of subtending switching units connected to the ingress side of selected UTM modules.

12. The UTM network of claim 11 wherein individual connections within a path in any of said virtual private networks are managed by said subtending switching units.

13. The UTM network of claim 11 wherein individual connections within a path in any of said virtual private networks are managed by said selected UTM modules.

14. The UTM network of claim 13 wherein each virtual network maintains a set of QOS definitions, the QOS definitions associated with each embedded virtual network being independent of QOS definitions associated with another of the embedded virtual networks.