Apparatus for translating frames of data transferred between heterogeneous local area networks

• US 5,560,038 A
• Filed: 11/28/1995
• Issued: 09/24/1996
• Est. Priority Date: 07/22/1994
• Status: Expired due to Fees

• Current Assignee: Network Peripherals, Inc. (Hale Capital Management LP)
• Original Assignee: Network Peripherals, Inc. (Hale Capital Management LP)
• Inventors: Haddock, Stephen R.
• Primary Examiner(s): Geckil, Mehmet B.
• Application Number:
  US08/563,345
• Time in Patent Office: 301 Days
• Field of Search: 395/800, 395/283, 395/308, 395/850, 395/200.17, 395/311, 370/60, 370/85, 370/95.1, 370/85.13-85.15
• US Class Current: 709/236
• CPC Class Codes: H04L 12/4625 Single bridge functionality, e.g. connection of two networks over a single bridge
• CPC Class Codes: H04L 69/08 Protocols for interworking; Protocol conversion
• CPC Class Codes: H04L 9/40 Network security protocols

Abstract

A translation engine for translating frames of data from one frame format to another frame format in the same manner as an IEEE 802.1D MAC-layer transparent bridge as required when transferring frames of data between interconnected heterogeneous local area networks. The translation engine is comprised of a variable length data pipeline capable of maintaining a constant synchronous data stream comprising frames of data from the input to the output of the data pipeline, without introducing any gaps in the data stream caused by removing fields of a frame, or causing the data stream to halt by inserting fields of a frame during translation of a frame from one frame format to another frame format.

Claims

1. An apparatus for translating a data frame by including or removing a field in said data frame while transferring said data frame from a first data bus to a second data bus, comprising:

a register array having;

an input coupled to said first data bus for receiving said data frame,

means for holding said field, and

an output for transmitting said data frame;

a selector having;

a first data input coupled to said first data bus for receiving said data frame,

a second data input coupled to said output of said register array for receiving said data frame,

a data output coupled to said second data bus for transmitting said data frame, and

a selector input for receiving a first signal to select said first data input and a second signal to select said second data input; and

,

decoder having;

an input coupled to said first data bus for receiving said data frame,

an output coupled to said selector input of said selector for transmitting, while said register array is holding said field, said first signal to select said first data input thereby removing from said data frame said field, or said second signal to select said second data input thereby including in said data frame said field,

means for decoding said data frame to determine when said output will transmit said first signal or said second signal.

2. The apparatus of claim 1, wherein said data frame is translated while being transmitted as a continuous stream of data.

3. An apparatus for translating a data frame by including or removing a field in said data frame while transferring said data frame between a first data bus and a second data bus, comprising:

a first register array having;

an input coupled to said first data bus for receiving said data frame,

means for holding a first field in said data frame, and

an output for transmitting said data frame;

a first selector having;

a first data input coupled to said first data bus for receiving said data frame,

a second data input coupled to said output of said first register array for receiving said data frame,

a data output for transmitting said data frame, and

a selector input for receiving a first signal to select said first data input and a second signal to select said second data input;

a first decoder having;

an input coupled to said first data bus for receiving said data frame,

an output coupled to said selector input of said first selector for transmitting, while said first register array is holding said first field, said first signal to select said first data input of said first selector thereby removing from said data frame said first field, or said second signal to select said second data input of said first selector thereby including in said data frame said first field, and

means for decoding said data frame to determine when said output of said first decoder will transmit said first signal or said second signal;

a second register array having;

an input coupled to said data output of said first selector for receiving said data frame,

means for holding a second field, and

an output for transmitting said data frame;

a second selector having;

a first data input coupled to said data output of said first selector for receiving said data frame,

a second data input coupled to said output of said second register array for receiving said data frame,

a data output coupled to said second data bus for transmitting said data frame, and

a selector input for receiving a third signal to select said first data input and a fourth signal to select said second data input; and

,

a second decoder having;

an input coupled to said first data bus for receiving said data frame,

an output coupled to said selector input of said second selector for transmitting, while said second register array is holding said second field, said third signal to select said first data input of said second selector thereby removing from said data frame said second field, or said fourth signal to select said second data input of said second selector thereby including in said data frame said second field, and

means for decoding said data frame to determine when said output of said second decoder will transmit said third signal or said fourth signal.

4. The apparatus of claim 3, wherein said data frame is transmitted as a continuous stream of data.