Multiplex communications – Pathfinding or routing – Through a circuit switch
Reexamination Certificate
1998-09-18
2003-08-26
Nguyen, Chau (Department: 2663)
Multiplex communications
Pathfinding or routing
Through a circuit switch
C370S375000, C370S465000
Reexamination Certificate
active
06611518
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to data communications, and more particularly, to methods and apparatus for connecting a plurality of devices to a data communications network through a switching system.
BACKGROUND OF THE INVENTION
Asynchronous Transfer Mode (ATM) is becoming an important standard for communications around the world. One reason for this is that ATM is essentially the only established standards based technology that has been designed from the beginning to accommodate the simultaneous transmission of data, voice and video. ATM is essentially a connection-oriented, switched based technology that provides dedicated bandwidth for each connection, a higher aggregate bandwidth, well defined connection procedures, and flexible access speeds ranging from Megabit to Gigabit speeds.
An ATM network basically consists of several ATM switches that are interconnected by various communication links. A typical ATM switch includes a programmable switch matrix or switch fabric that supports the interconnectivity for both local devices and other remote ATM switches and devices. The flexibility of the switch fabric allows for virtual circuits to be established between nodes using switching protocols and commands. Depending upon the type of transfer, these virtual circuits provide point-to-point connections that can be unidirectional or bidirectional. In this manner, an ATM network is essentially woven using the switch fabric provided by the various ATM switches.
FIG. 1
is a block diagram depicting a typical ATM network
100
having an ATM switch
102
that provides network connectivity for several devices
104
, for example, numbered 1 through N. Devices
104
can include computers, hosts, routers, gateways, peripherals, appliances, and other like devices that are configured to send and/or receive the type of information (e.g., data, voice, video) carried by ATM network
100
.
As shown, devices
104
are each connected to a dedicated device interface port
106
(numbed 1 through N) within ATM switch
102
. On the network side of ATM switch
102
, there are several network interface ports
108
(also, numbered 1 through N). ATM switch
102
provides the switch fabric that selectively connects together (and later disconnects) specified device interface ports and/or network interface ports to help establish a virtual circuit though ATM network
100
. For example, in
FIG. 1
, a virtual circuit is depicted by the solid and dashed lines connecting device (#
2
)
104
to remote device
110
, through ATM switch
102
and network links
112
. Network links
112
typically includes one or more communication media, such as, for example, terrestrial and/or satellite communication lines/services.
As further depicted in
FIG. 1
, ATM switch
102
is limited in the number of devices
104
that can be supported by the “N” number of device interface ports
106
and the size of the switch fabric (i.e., N×N). For example, certain ATM switches provide a 16×16 switch fabric (i.e., where N=16) having sixteen device interface ports
106
and sixteen network interface ports
108
. As such, these ATM switches are limited to supporting sixteen devices
104
. Larger ATM switches are available, for example, 32×32 switch fabrics are provided by certain manufacturers. These 32×32 and even larger ATM switches, however, tend to be very complex and expensive.
As can be appreciated, the fixed size and high cost of an ATM switch, can be problematic for users that want to “phase-in” an ATM network and/or provide for future expansion of the ATM network, for example, by adding additional devices to the ATM switch. Indeed, users, such as small businesses, that have limited communication funds may be forced to forego the development of an ATM network until such time as they can justify the purchase of a larger ATM switch. Other users may be forced to purchase too large an ATM switch. In a worse case scenario, the large ATM switch that is purchased exceeds their current demands, but will eventually lack the capacity to support their future growth and additional demands. Thus, there is a need for methods and apparatus that provide a more flexible and cost-effective ATM switching capability.
SUMMARY OF THE INVENTION
The methods and apparatus of the present invention provide a more flexible and cost-effective switching capability by allowing device interface ports within a switch fabric to be dynamically assigned in a manner that allows several devices to selectively access a single device interface port.
Thus, for example, assume that a user has a current need to provide connectivity for twelve devices. Assume also that the user plans to expand that need to twentyeight devices in the future. In the past, such a user might decide to incrementally purchase two 16×16 switches, or initially purchase one larger 32×32 switch. Both of these choices tend to be rather expensive and wasteful. Given the present invention, however, such a user can purchase one 16×16 switch, for example, and economically add configurable connections that allow up to about forty-eight devices to access the network through the 16×16 switch.
With this example in mind, in accordance with certain aspects of the present invention, flexible network connectivity is provided to a plurality of devices through a network interface that can be dynamically configured and reconfigured as needed, without interrupting existing network connections, to meet the current communication needs of the user.
In accordance with other aspects of the present invention, the various methods and apparatus provided allow a data communication system to exceed the network connectivity capabilities of a conventional network switch.
In accordance with still other aspects of the present invention, the various methods and apparatus provided allow for incremental growth of a system to more cost-effectively meet the users communication needs.
In accordance with further aspects of the present invention, the various methods and apparatus provide a lower cost solution to connecting a plurality of devices to a network through a limited number of communication paths.
In accordance with still further aspects of the present invention, the various methods and apparatus provided tend to reduce the complexity of a network switch by significantly reducing the size of the switch fabric therein, for example.
In accordance with additional aspects of the present invention, the various methods and apparatus provide enhanced configuration capabilities that can be used to automatically test various switch and network configurations and connections.
By way of example, the above stated needs and others are met by an apparatus for selectively connecting a plurality of external devices to a network, in accordance with certain embodiments of the present invention. The apparatus includes a selector and a switch. The selector has a plurality of input ports and a plurality of output ports. In certain preferred embodiments, the number of input ports within the selector is greater than the number of output ports within the selector, for example, certain selectors have at least about forty-eight input ports and at least about sixteen output ports.
While each of the input ports is configured to be connected to a different external device, the selector is dynamically configurable to selectively couple at least one of the input ports to at least one of the output ports. Thus, for example, at least one of the forty-eight input ports, or a subset thereof, can be selectively coupled to at least one of the sixteen output ports, or a subset thereof. This allows several devices to gain access to the network, without requiring a dedicated device interface port within the switch for each of the devices.
The switch has a plurality of device interface ports, for example “N” number, each of which is coupled to a corresponding output port in the selector. The switch is configured to switchably connect an individual device interface port to an identified n
Ngo Gordon K.
Rhee Se Hyeon
Viswanathan Senthil Kumar
Lee Andy
Nguyen Chau
Samsung Electronics Co,. Ltd.
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