Apparatus and method for providing fire wall protection for systems in communication with an a synchronous transfer mode system

A method of operating an edge device for use with a connection-oriented system having a plurality of communication connections, the edge device including a memory having a plurality of memory locations, the method comprising:

• receiving data from a particular connection of the communication connections;
• obtaining a value representative of the number of the memory locations used by the particular connection;
• placing the data in a particular memory location of the memory locations if the value representative of the number of memory locations used by the particular connection indicates that at least one memory location of the memory locations for the particular connection is available;
• not allowing the data to reach the particular memory location if the value representative of the number of memory locations used by the particular connection indicates that at least one memory location of the memory locations for the particular connection is not available;
• adjusting the value of the number of the memory locations used by the particular connection when a memory location other than the particular memory location no longer must store the cell;
• and
• snooping the memory before performing the adjusting step.

A method of operating an edge device for use with an asynchronous transfer mode system having a plurality of communication connections, the edge device including a buffer having a plurality of buffer locations coupled between an asynchronous transfer mode interface and a system interface, the method comprising:

• receiving a cell associated with a particular connection of the communication connections;
• reading an indication of the number of buffer locations used by the particular connection from a storage location;
• placing the cell in a particular buffer location of the buffer locations if the number of buffer locations used by the particular connection is below a threshold, and adjusting the indication of the number of buffer locations used by the particular connection;
• and
• not allowing the cell to reach the particular buffer locations if the number of buffer locations used by the particular connection is above or equal to the threshold;
• wherein the threshold is greater than the number of buffer locations in the buffer divided by the number of connections.

A method of operating an edge device for use with an asynchronous transfer mode system having a plurality of communication connections, the edge device including a buffer having a plurality of buffer locations coupled between an asynchronous transfer mode interface and a system interface, the method comprising:

• receiving a cell associated with a particular connection of the communication connections;
• reading an indication of the number of buffer locations used by the particular connection from a storage location;
• placing the cell in a particular buffer location of the buffer locations if the number of buffer locations used by the particular connection is below a threshold, and adjusting the indication of the number of buffer locations used by the particular connection;
• not allowing the cell to reach the particular buffer locations if the number of buffer locations used by the particular connection is above or equal to the threshold;
• wherein the threshold is greater than the number of buffer locations in the buffer divided by the number of connections;
• adjusting the indication of the number of buffer locations used by the particular connection when a buffer location other than the particular buffer location no longer must store the cell;
• and
• snooping the buffer before performing the adjusting step.