Systems and methods for data unit modification

• US 7,007,208 B1
• Filed: 05/30/2003
• Issued: 02/28/2006
• Est. Priority Date: 05/31/2002
• Status: Active Grant

• Current Assignee: Viavi Solutions, Inc. (Lumentum Holdings Inc.)
• Original Assignee: Finisar Corporation (II-VI Incorporated)
• Inventors: Cicchetti, Chris, Hibbert, Geoffrey, Poelstra, Henry
• Primary Examiner(s): Ton, David
• Application Number:
  US10/448,917
• Time in Patent Office: 1,005 Days
• Field of Search: 380/209, 345/531, 709/230, 709/231, 370/392, 712/228, 714/712, 341/51
• US Class Current: 714/712
• CPC Class Codes: H04L 1/24 Testing correct operation

Abstract

A modification subsystem suitable for introducing user-defined errors into a designated data unit substantially in real time, so as to facilitate evaluation of the response of a high speed data communications system to errors as such are exemplified in the modified data unit. The modification subsystem includes a modification logic and state machine that communicates with a command stack memory and one or more jamming mode registers. Upon locating and identifying the designated data unit in a data stream, the modification logic and state machine accesses a jam setting stored in a jam mode register and, if it is determined that the modification that corresponds to the jam setting is valid, modifies the designated data unit in accordance with the jam setting. If the proposed modification is invalid, the modification is aborted.

Claims

1. A modification subsystem for use in connection with a data stream carrying a plurality of data units, the modification subsystem comprising:

(a) a command stack memory;

(b) at least one jamming mode register that stores a jam setting corresponding to a bytewise truncation of a designated data unit carried in the data stream; and

(c) a modification logic and state machine in communication with the command stack memory and the at least one jamming mode register, the modification logic and state machine being configured to receive the data stream.

2. The modification subsystem as recited in claim 1, wherein the command stack memory and the at least one jamming mode register are configured to receive input from a host device.

3. The modification subsystem as recited in claim 1, wherein the jamming mode register contains a global jam command.

4. The modification subsystem as recited in claim 1, wherein the bytewise truncation comprises a bytewise truncation of a payload of the designated data unit.

5. The modification subsystem as recited in claim 1, wherein the bytewise truncation comprises one of:

a Gigabit Ethernet frame truncation;

truncation of an IP frame embedded in a Gigabit Ethernet frame; and

, truncation of a TCP frame embedded in an IP frame that is embedded in a Gigabit Ethernet frame.

6. The modification subsystem as recited in claim 1, wherein the modification logic and state machine is configured to receive a jam signal.

7. The modification subsystem as recited in claim 1, wherein the modification logic and state machine is configured to receive trigger condition information.

8. The modification subsystem as recited in claim 1, wherein the modification logic and state machine is configured to receive information concerning the location and alignment of the designated data unit.

9. A modification subsystem for use with a high speed communications system that substantially conforms with the Gigabit Ethernet physical specification, the high speed communications system being configured to operate in conjunction with a data stream carrying Gigabit Ethernet data frames, and the modification subsystem comprising:

(a) a command stack memory;

(b) at least one jamming mode register that stores a jam setting corresponding to a truncation of a designated Gigabit Ethernet data frame; and

(c) a modification logic and state machine in communication with the command stack memory and the at least one jamming mode register.

10. The modification subsystem as recited in claim 9, wherein the jamming mode register contains at least one jam mode value.

11. The modification subsystem as recited in claim 9, wherein the command stack memory and the at least one jamming mode register are configured to receive input from a host device.

12. The modification subsystem as recited in claim 9, wherein the modification logic and state machine is configured to receive a jam signal.

13. The modification subsystem as recited in claim 9, wherein the modification logic and state machine is configured to receive trigger condition information.

14. The modification subsystem as recited in claim 9, wherein the modification logic and state machine is configured to receive information concerning the location and alignment of the designated Gigabit Ethernet data frame.

15. The modification subsystem as recited in claim 9, wherein the truncation of the designated Gigabit Ethernet data frame comprises one of:

a Gigabit Ethernet payload truncation;

an IP payload truncation; and

, a TCP payload truncation.

16. The modification subsystem as recited in claim 9, wherein the truncation of the designated Gigabit Ethernet data frame comprises a byte level truncation of the designated Gigabit Ethernet data frame.

17. A method for altering a designated data unit carried in a data stream, the method comprising:

(a) receiving the data stream;

(b) receiving a jam signal;

(c) accessing, in response to receipt of the jam signal, a jam setting that corresponds to a bytewise truncation of the designated data unit;

(d) determining whether the bytewise truncation is valid;

(e) performing the bytewise truncation on the designated data unit, if a determination has been made that the bytewise truncation is valid; and

(f) aborting the bytewise truncation of the designated data unit, if a determination has been made that the bytewise truncation is invalid.

18. The method as recited in claim 17, wherein performing the bytewise truncation of the designated data unit comprises performing a bytewise truncation of one of:

a Gigabit Ethernet frame;

an IP frame embedded in a Gigabit Ethernet frame; and

, a TCP frame embedded in an IP frame that is embedded in a Gigabit Ethernet frame.

19. The method as recited in claim 18, wherein the bytewise truncation comprises truncation of an IP frame embedded in a Gigabit Ethernet frame, and the method further comprises:

(a) determining whether an IP frame indicator is present in the Gigabit Ethernet frame; and

(b) aborting the bytewise truncation of the IP frame if no IP frame indicator is present in the Gigabit Ethernet frame.

20. The method as recited in claim 18, wherein the bytewise truncation comprises truncation of a TCP frame embedded in an IP frame that is embedded in a Gigabit Ethernet frame, and the method further comprises:

(a) determining whether an IP frame indicator is present in the Gigabit Ethernet frame;

(b) aborting the bytewise truncation of the TCP frame if no IP frame indicator is present in the Gigabit Ethernet frame;

(c) determining, if an IP frame indicator is present in the Gigabit Ethernet data frame, whether a TCP frame indicator is present in the IP frame; and

(d) aborting the bytewise truncation of the TCP frame if no TCP frame indicator is present in the IP frame.

21. The method as recited in claim 17, wherein determining whether the bytewise truncation is valid comprises:

(a) counting through the designated data unit, up to a point that delimits a length of the bytewise truncation;

(b) determining that the bytewise truncation is invalid, if an end of the designated data unit is encountered prior to the point delimiting the bytewise truncation length; and

(c) determining that the bytewise truncation is valid, if the end of the designated data unit is not encountered prior to the point delimiting the bytewise truncation length.

22. The method as recited in claim 17, wherein at least the accessing, determining, and truncating processes are performed in response to receipt of the jam signal.

23. The method as recited in claim 17, further comprising receiving triggering information concerning the designated data unit.

24. The method as recited in claim 17, further comprising receiving location and alignment information concerning the designated data unit.

25. The method as recited in claim 17, further comprising transmitting the designated data unit, regardless of whether the designated data unit has been modified.

26. The method as recited in claim 17, further comprising transmitting the data stream, regardless of whether the designated data unit has been modified.

27. A method for altering a designated Gigabit Ethernet data frame carried in a data stream, the method comprising:

(a) receiving the data stream;

(b) receiving a jam signal;

(c) accessing, in response to receipt of the jam signal, a jam setting that corresponds to a truncation of the designated Gigabit Ethernet data frame;

(d) determining whether the truncation is valid;

(e) truncating the designated Gigabit Ethernet data frame if a determination has been made that the truncation is valid; and

(f) aborting truncation of the designated Gigabit Ethernet data frame, if a determination has been made that the truncation is not valid.

28. The method as recited in claim 27, wherein truncating the designated Gigabit Ethernet data frame comprises performing a bytewise truncation of the designated Gigabit Ethernet data frame.

29. The method as recited in claim 27, wherein the payload truncation comprises a truncation of one of:

a Gigabit Ethernet payload;

an IP payload; and

, a TCP payload.

30. The method as recited in claim 27, wherein the truncation of the designated Gigabit Ethernet data frame is performed at an 8 bit boundary within the data stream.

31. The method as recited in claim 27, wherein determining whether the truncation is valid comprises:

(a) counting through the designated Gigabit Ethernet data frame, up to a point that delimits a length of the bytewise truncation;

(b) determining that the bytewise truncation is invalid, if the end of the designated Gigabit Ethernet data frame is encountered prior to the point delimiting the bytewise truncation length; and

(c) determining that the bytewise truncation is valid, if the end of the designated Gigabit Ethernet data frame is not encountered prior to the point delimiting the bytewise truncation length.

32. The method as recited in claim 27, wherein at least the accessing, determining and truncating processes are performed substantially in real time.

33. The method as recited in claim 27, wherein, if the truncation is performed, a corresponding number of idles are inserted into the modified designated Gigabit Ethernet data frame.

34. The method as recited in claim 27, further comprising transmitting the designated Gigabit Ethernet data frame, regardless of whether the designated Gigabit Ethernet data frame has been truncated.

35. The method as recited in claim 27, further comprising repeating at least (a) through (e).

36. A computer program product for implementing a method for altering a designated portion of a data stream, the computer program product comprising:

a computer readable medium carrying computer executable instructions for performing the method, wherein the method comprises;

(a) receiving the data stream;

(b) receiving a jam signal;

(c) accessing, in response to receipt of the jam signal, a jam setting that corresponds to a bytewise truncation of the designated data unit;

(d) determining whether the bytewise truncation is valid;

(e) performing the bytewise truncation on the designated data unit, if a determination has been made that the bytewise truncation is valid; and

(f) aborting the bytewise truncation of the designated data unit, if a determination has been made that the bytewise truncation is invalid.