System having central processor for transmitting generic packets to another processor to be altered and transmitting altered packets back

What is claimed is:

1. An internetworking system for exchanging packets of information between networks, said system comprising:

a network interface module for connecting a network to said system, receiving packets from the network in a native packet format used by the network and converting each received native packet having a generic format common to all networks connected to said system, and converting each said generic packet to the native packet format for transmission to the network,

a communication channel for carrying said generic packets to and from said network interface module, said channel having bandwidth,

a first processing module for controlling dynamic allocation and deallocation of said channel bandwidth to the network connected to said system via said network interface module,

a second processing module for receiving all said generic packets put on said channel by said network interface module, determining whether each said generic packet needs to be bridged or routed to a destination network interface module, and bridging each said generic packets determined to need bridging;

a third processing module for receiving and routing each said generic packet determined to need routing from said second processing module via said channel, said third processing module routing those generic packets received from said second processing module by altering those generic packets to contain appropriate destination information and transmitting those altered packets to said second processing module; and

said second processing module also for receiving said altered generic packets, determining the destination network interface for each of said altered generic packets, and transmitting those altered generic packets to the destination network interface module.

2. The system of claim 1 wherein said network interface module converts each of the received native packets to packets having said generic format by appending information to each of the received native packets.

3. The system of claim 1 wherein time division multiplexing is utilized in said dynamic allocation and deallocation of said communication channel bandwidth by said first processing module.

4. The system of claim 1 wherein said second processing module comprises dedicated electronic components for performing all functions required of said second processing module including receiving all said generic packets put on said channel by said network interface module and determining a destination network interface module for each said generic packet on said channel and whether each said generic packet needs to be bridged to the destination network interface module.

5. The system of claim 1 wherein said second processing module comprises dedicated electronic components for performing all functions required of said second processing module including receiving all said generic packets put on said channel by said network interface module and determining a destination network interface module for each said generic packet on said channel and whether each said generic packet needs to be routed to the destination network interface module.

6. The system of claim 1 wherein said network interface module may be inserted into said system while said system is operational substantially without disruption to the operation of said system, said first processing module dynamically allocating said communication channel bandwidth to said network interface module.

7. The system of claim 1 wherein said network interface module and any of said processing modules may be removed from said system while said system is operational substantially without disruption to the operation of said system if a redundant duplicate of the removed module is present in said system, said first processing module dynamically deallocating said communication channel bandwidth previously allocated to the removed module.

8. The system of claim 1 further comprising at least one redundant network interface module which is a duplicate of said network interface module to provide fault tolerance.

9. The system of claim 1 wherein a logical network can be formed which includes one or more users from a plurality of physical networks connected to said system.

10. An internetworking system for performing both routing and bridging functions to exchange packets of information between computer networks, said system comprising:

a network interface module for connecting a computer network to said system, receiving packets from the computer network in a native packet format used by the computer network and converting each of the received native packets to a packet having a generic format common to all computer networks connected to said system, and converting each of said generic packet to the native packet format for transmission to the computer network,

a communication channel for carrying said generic packets to and from said network interface module, said channel having bandwidth,

a first processing module for controlling dynamic allocation and deallocation of said channel bandwidth to the computer network connected to said system via said network interface module,

a second processing module for receiving all said generic packets put on said channel by said network interface module, determining whether each said generic packet needs to be routed or bridged to a destination network interface module, and transmitting those generic packets determined to need bridging to the destination network interface module via said channel,

a third processing module for receiving each of said generic packets determined to need routing from said second processing module via said channel, altering those generic packets determined to need routing to contain appropriate destination information, and transmitting those altered generic packets back to said second processing module via said channel, and

said second processing module also for receiving said altered generic packets, determining the destination network interface for each of said altered generic packets, and transmitting each of the altered generic packets to the destination network interface module.

11. An internetworking system for performing both routing and bridging functions, comprising:

a network interface card for connecting a network to said system, receiving packets from the network in a native packet format used by the network and converting each received native packet to a packet having a generic format common to all networks connected to said system, and converting each said generic packet to the native packet format for transmission to the network,

a bus for carrying said generic packets to and from said network interface card, said bus having bandwidth,

a control processor for controlling dynamic allocation and deallocation of said bus bandwidth to the network connected to said system via said network interface card,

a central switch processor for receiving all said generic packets put on said bus by said network interface card, determining whether each said generic packet needs to be routed or bridged to the destination network interface card, and

a router engine for receiving and routing each said generic packet determined to need routing from said central switch processor via said bus, said router engine routing those generic packets received from said central switch processor by altering those generic packets to contain appropriate destination information and transmitting those altered packets to said central switch processor;

said central switch processor also for receiving said altered generic packets and determining the destination network interface for each of said altered generic packets.

Description Submit all comments and votes

FIELD OF THE INVENTION

This invention relates to internetworking devices and methods, and more particularly, to a broadband enterprise switch capable of interconnecting a variety of networks.

BACKGROUND OF THE INVENTION

Known compute-intensive network applications demand increased bandwidth. With the deployment of multi-media workstations, the use of image processing in the healthcare and banking industries, electronic publishing, and CAD/CAE applications in the engineering environment, an internetworking product which can support performance requirements across practically any geographic distance is required.

In general, a network includes a collection of autonomous machines which are interconnected (e.g., via wires, optical fibers, satellites, etc.) in order to run user (i.e., application) programs. A computer network is a network which typically includes at least one autonomous computer. The term network as used herein generally should be taken to mean computer network. Internetworking generally means the connection of two or more computer networks to allow an exchange of information between the networks. The information exchanged between ("inter") the various networks and among ("intra") the individual networks typically is contained in discrete packets which can be arranged in a variety of formats.

Bridges and routers generally are internetworking devices which can be used to interconnect or extend packet-based local area networks (LANs) or subnetworks. Both bridges and routers can make forwarding or routing decisions based on information in the LAN packet headers. A bridge differs fundamentally from a router. A bridge typically relays Media Access Control (MAC) layer (or data link layer which is layer two in the OSI model) frames and decisions are made based on information in the frame header. A router relays network layer (layer three in the OSI model) datagrams an decisions are based on information in the network layer header. This fundamental difference affects the way each type of device operates, and consequently, the applications to which it is best suited.

Bridges and routers currently employed for internetworking typically use shared-bus architectures in which bandwidth is shared between networks on a statistical first come, first served basis.

Because network downtime usually equates to lost productivity, lost business, and user dissatisfaction, many companies desire a reliable, robust internetworking device that provides high system and network availability as well as the security of non-stop networking for many, if not all, network applications.

To be most useful, an internetworking device should maximize reliability, availability, and serviceability. Also, the device should provide organizations with the flexibility and the performance capability required to accommodate organizational growth and technological evolution.

SUMMARY OF THE INVENTION

In general, in one aspect, the invention features an internetworking system for exchanging packets of information between networks, the system comprising a network interface module for connecting a network to the system, receiving packets from the network in a native packet format used by the network and converting each received native packet to a packet having a generic format common to all networks connected to the system, and converting each of the generic packets to the native packet format for transmission to the network; a communication channel having bandwidth and for carrying the generic packets to and from the network interface module; a first processing module for controlling dynamic allocation and deallocation of the channel bandwidth to the network connected to the system via the network interface module; and a second processing module for receiving all of the generic packets put on the channel by the network interface module, determining a destination network interface module for each of the generic packets on the channel, determining whether each of the generic packets needs to be bridged to the destination network interface module, and transmitting each of the generic packets determined to need bridging to the destination network interface module via the channel.

Embodiments of this aspect of the invention include the following features. Time division multiplexing may be utilized in the dynamic allocation and deallocation of the communication channel bandwidth performed by the first processing module. The second processing module may comprise dedicated electronic components for performing all functions required of the second processing module including receiving all of the generic packets put on the channel by the network interface module and determining a destination network interface module for each of the generic packets on the channel and whether each of the generic packets needs to be bridged to the destination network interface module. The network interface module and any of the processing modules may be inserted or removed from the system while the system is operational substantially without disruption to the operation of the system in which case the first processing module dynamically allocates or deallocates the communication channel bandwidth to the network interface module and any of the processing modules which are so inserted or removed. This feature is referred to as "hot swapping." The system further may comprise at least one redundant network interface module which is a duplicate of the network interface module to provide fault tolerance. A logical network can be formed which includes one or more users from a plurality of physical networks connected to the system.

In other embodiments of this aspect of the invention, the second processing module also may determine whether each of the generic packets needs to be routed to the destination network interface module, and the system may further comprise a third processing module for receiving each of the generic packets determined to need routing from the second processing module via the channel and transmitting those generic packets back to the second processing module via the channel and the second processing module transmitting those generic packets to the destination network interface module via the channel. Time division multiplexing may be utilized in the dynamic allocation and deallocation of the communication channel bandwidth performed by the first processing module. The second processing module can comprise dedicated electronic components. The network interface module and any of said processing modules may be "hot swapped." The system further may comprise at least one redundant network interface module for fault tolerance. A logical network can be formed which includes one or more users from a plurality of networks connected to the system.

An internetworking system according to the invention can integrate both bridging and routing functions. Alternatively, the system can operate as a pure bridging device or as a multiprotocol router. The system can support performance requirements across practically any geographic distance and does not use a contention bus which typically causes bottlenecks.

The system can provide high availability and the security of essentially non-stop operation. The system maximizes reliability, availability, and serviceability. Also, the system can provide organizations with the flexibility and the performance capability required to accommodate organizational growth and technological evolution.

Other aspects, features, objects, and advantages of the invention will become apparent from the following description and from the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram of a variety of networks interconnected using several broadband enterprise switches according to the invention;

FIG. 2 is a diagram of a variety of networks connected to a bus of a broadband enterprise switch;

FIG. 3 is a diagram of various networks connected to various electronic processor modules via a broadband enterprise switch bus;

FIG. 4 is a diagram of a format of an internal packet which may be used by a broadband enterprise switch;

FIG. 5 is a flowchart diagram of a reconfiguration feature which may be used by a broadband enterprise switch;

FIG. 6 is a flowchart diagram of a "hot swap" feature which may be used by a broadband enterprise switch;

FIG. 7 is a diagram of a broadband enterprise switch including an optical bypass switch;

FIG. 8 is a diagram of a variety of local area networks interconnected by several broadband enterprise switches;

FIG. 9 is a diagram of a system using frame relay communication;

FIG. 10 is a diagram showing the generation of an internal packet used in a broadband enterprise switch;

FIGS. 11A, 11B, and 11C are diagrams illustrating a "logical" (or "virtual") network feature of a broadband enterprise switch according to the invention;

FIG. 12 is a diagram of another embodiment of a broadband enterprise switch network according to the invention;

FIG. 13 is a diagram of a frame relay interconnection of broadband enterprise switches;

FIG. 14 is a diagram of a broadband enterprise switch in a rack-mount form;

FIG. 15 is a diagram of one possible bus bandwidth allocation in accordance with the invention;

FIG. 16 is a diagram of two components which may be included in each network interface module of a broadband enterprise switch according to the invention;

FIG. 17 is a table summarizing features of some network interface modules according to the invention; and

FIG. 18 is a table identifying fields of an internal packet format which may be used by a broadband enterprise switch according to the invention.

DETAILED DESCRIPTION

Overview

In one embodiment, the invention includes a Broadband Enterprise Switch (BES) which is a high performance, high availability internetworking nodal processor combining, for example, native-speed local area network (LAN) interconnection, high-bandwidth wide area network (WAN) access, and non-stop networking for mission critical applications. The BES can be used to interconnect a plurality of individual networks such as many or all of the networks operated by a large corporation whose operations could be located in different geographic areas.

The BES can utilize an integrated internetworking architecture to combine the benefits of multiprotocol routing and high performance bridging, and may be capable of supporting applications that span multiple networks. The BES can include, for example, standard interfaces for FDDI, Ethernet, and Token Ring LANs as well as T1, E1, and DS3 interfaces for linking remote and/or local LANs (an example of a local LAN might be a campus network) together across a public or private WAN.

The BES can provide high performance LAN internetworking via a central switch design that moves traffic between networks at full native network speeds, thereby effectively removing the bottlenecks that occur with known network interconnection devices. The throughput of the BES can allow full utilization of the available bandwidth of networks interconnected by the BES and allow users to take full advantage of the increased capacity available from, for example, known fiber optic technology such as FDDI and DS3, as well as future services such as SONET.

The BES also can include a redundant architecture to achieve high reliability, as well as intelligent self-diagnosing and self-healing operations.

One example of the use of the BES to interconnect various networks is shown in FIG. 1. Referring to FIG. 1, a first BES 10 may interconnect an Ethernet LAN 12 and a Token Ring LAN 14 to an FDDI "backbone" 16. Another BES 18 can interconnect a Token Ring LAN 20, an Ethernet LAN 22, and a Network Management System (NMS) 24 to the FDDI 16. A third BES 26 might be used to interconnect the FDDI 16 to a fourth BES 28 and/or a fifth BES 30 via a WAN 32. The fourth and fifth BESs 28, 30 can themselves have one or more LANs (or WANs) connected. In the example of FIG. 1, the fourth BES 28 interconnects two Ethernet LANs 34, 36 to the rest of the system, and the fifth BES 30 interconnects two Ethernet LANs 38, 40 and a Token Ring LAN 42. Note that FIG. 1 is only an example; a variety of other networks, whether LANs, WANs, or metropolitan area networks (MANs), also may be interconnected via one or more BESs.

Some benefits of the BES are high performance transparent internetworking, a resilient architecture which provides non-stop internetworking, an extendable standards-based platform, and a comprehensive manageability capability.

Depending on a particular embodiment, the BES can support high performance LAN internetworking and high speed WAN interconnection with an aggregate system throughput of approximately 400,000 packets per second (pps). With the ability to interconnect networks at their full native bandwidth, the BES can facilitate the networking of high-speed applications that span local, metropolitan, and wide areas. The BES may extend performance across geographic boundaries and remove the typical interconnect bottlenecks that decrease performance and service satisfaction to the end users of known systems.

In a corporate campus or metropolitan-area application, the BES can maximize the utility of a backbone interconnect medium such as 100 megabits per second (Mbps) FDDI. A campus network can be created that, for example, transparently interconnects lower speed departmental Ethernet and Token Ring LANs via an FDDI building backbone, and internetworks multiple FDDI bu