System and method for testing the upstream channel of a cable network

• US 7,509,542 B2
• Filed: 11/15/2005
• Issued: 03/24/2009
• Est. Priority Date: 11/01/2000
• Status: Expired due to Fees

• Current Assignee: Sunrise Telecom Incorporated
• Original Assignee: Sunrise Telecom Incorporated
• Inventors: Elliott, Herman B., Barker, James E., Richards, Robert L., Jaworski, Richard C.
• Primary Examiner(s): KERVEROS, DEMETRIOS C
• Application Number:
  US11/164,247
• Publication Number:
  US 20060048200A1
• Time in Patent Office: 1,225 Days
• Field of Search: 714/704, 714/716, 714/712, 714/746, 714/748, 714/749, 714/752, 714/753
• US Class Current: 714/704
• CPC Class Codes: H04L 12/2801 Broadband local area networks
• CPC Class Codes: H04L 43/50 Testing arrangements

Abstract

A system and method for testing a portion of a cable network provides a pattern generator, addresser, forward error corrector, and comparator. The system and method is particularly adapted to testing the upstream channel in a cable network. The pattern generator generates a test signal. The addresser addresses the signal to a known server and also instructs the known server to return the test signal to the test system. The forward error corrector corrects errors introduced in the test signal in transmission from the known server to the test system. The comparator then compares the returned test signal to the originally transmitted test signal to determine the performance of the back channel. Preferably, the comparator uses a bit error rate test to determine the performance of the back channel.

Claims

1. A method for determining the performance of a portion of a network, the method comprising:

transmitting a signal from a transmission point onto the portion of the network;

receiving the signal at a destination;

returning the signal to the transmission point;

correcting errors introduced into the signal in transmission from the destination to the transmission point; and

determining the performance of the portion of the network from the transmission point to the destination.

2. The method of claim 1 further comprising the step of determining the performance of the portion of the network using the corrected signal.

3. The method of claim 2 wherein the correcting step uses forward error correction techniques.

4. The method of claim 1 wherein the correcting step uses forward error correction techniques.

5. The method of claim 4 wherein the correcting the second errors further comprises:

determining residual errors in portions of the signal received at the transmission point; and

discarding the portions of the signal that contain residual errors.

6. The method of claim 4 wherein comparing the signals tests for bit error rate, block error rate, or a combination thereof.

7. The method of claim 1 wherein the method repeats.

9. The method of claim 1 wherein the network is a cable network.

10. The method of claim 9 wherein the destination is a cable modem termination system.

11. The method of claim 1 wherein the portion of the cable network is a local area cable loop.

12. The method of claim 11 wherein the performance of an upstream channel of the local area cable loop is determined.

13. The method of claim 12 wherein the transmitting step transmits the signal in the upstream channel.

14. The method of claim 12 wherein the signal is returned in a forward channel of the local area cable loop.

8. A method for determining the performance of a portion of a network, the method comprising:

transmitting a signal from a transmission point onto the portion of the network;

receiving the signal at a destination;

detecting errors in the signal received at the destination;

discarding portions of the signal received at the destination that contain errors;

returning the non-discarded signal portions to the transmission point;

determining the magnitude of the discarded portions of the signal from the returned, non-discarded portions;

using a block error rate test to determine the performance of the portion of the network; and

determining the performance of the portion of the network from the transmission point to the destination.

15. A method for determining the performance of a portion of a network,the method comprising:

transmitting a test packet from a tester onto an upstream portion of the network;

receiving the test packet at a cable modem termination system (CMT);

returning the test packet from the CMTS to the testere on a downstream portion of the Network; and

using the test packet in the tester to determine the performance of the upstream Portion of the network.

16. The method of claim 15 further comprising:

transmitting a plurality of test packets from the tester onto the upstream portion of the network; and

using all of the plurality of test packets to determine the performance of the upstream portion of the network.

17. The method of claim 15 further comprising:

transmitting a plurality of test packets from the tester onto the upstream portion of the network; and

discarding test packets with errors by the CMTS.

18. The method of claim 15 wherein the performance is measured as a block error rate.

19. The method of claim 15 wherein the performance is measured as a bit error rate.

20. The method in claim 15 where the performance is measured as a function of discarded packets.

21. The method in claim 15 wherein the network is a cable network.

22. The method in claim 15 wherein:

the transmitting step transmits the test packet in the upstream channel of a cable network; and

the returning step returns the test packet in the forward channel of a cable network.

23. The method in claim 15 wherein:

the transmitting step transmits the test packet in the upstream channel of an Internet network; and

the returning step returns the test packet in the forward channel of an Internet.

24. The method in claim 15 wherein transmitting the test packet transmits a test packet containing information related to the test packet used by the tester to determine the performance.

25. The method of claim 15 wherein the method repeats.

26. The method in claim 15 wherein:

transmitting a plurality of test packets from the tester onto the upstream portion of the network; and

transmitting the plurality of test packets transmits the plurality of test packets containing a pattern that repeats in each of the plurality of test packets.

27. The method in claim 15 wherein:

transmitting a plurality of test packets from the tester onto the upstream portion of the network; and

transmitting the plurality of test packets transmits the plurality of test packets with information identifying each of the plurality of test packets as a test packet.

28. The method in claim 15 wherein:

transmitting a plurality of test packets from the tester onto the upstream portion of the network;

returning the plurality of test packets from the CMTS to the tester on the downstream portion of the network; and

ignoring an error in a test packet of the plurality of test packets from the CMTS.

29. The method in claim 15 further comprising transmitting information of the performance to a computer for monitoring the network.

30. The method in claim 15 further comprising monitoring a cable modem using a computer.

31. The method in claim 15 further comprising monitoring performance using a computer.