Data connection quality analysis apparatus and methods

• US 7,489,641 B2
• Filed: 04/25/2005
• Issued: 02/10/2009
• Est. Priority Date: 04/25/2005
• Status: Active Grant

• Current Assignee: Viavi Solutions, Inc. (Lumentum Holdings Inc.)
• Original Assignee: Acterna LLC (Lumentum Holdings Inc.)
• Inventors: Gotwals, Michael, Massey, Gregory, Miller, Walter
• Primary Examiner(s): LEE, CHI HO A
• Application Number:
  US11/114,522
• Publication Number:
  US 20060250967A1
• Time in Patent Office: 1,387 Days
• Field of Search: 370/241.1, 370/248
• US Class Current: 370/241.1
• CPC Class Codes: H04L 12/2801 Broadband local area networks
• CPC Class Codes: H04L 43/50 Testing arrangements

Abstract

A test device enables DOCSIS link testing in a HFC network without requiring the CMTS or other router at the headend of the HFC network to respond to ICMP messages. The test device includes a test packet generator for generating test packets having a destination Internet protocol (IP) address associated with a test device, a memory for storing transmission parameters of the test packets, and a test packet evaluator associated with the IP address in the generated test packets. The test packet evaluator receives the generated test packets after the test packets have been routed through a router at a head end of a HFC network and compares reception parameters for the received test packets to the transmission parameters stored in the memory.

Claims

1. A test device for evaluating data communication paths over a hybrid fiber cable (HFC) network comprising:

a test packet generator for generating test packets;

a memory for storing transmission parameters of the test packets; and

a test packet evaluator for receiving the generated test packets after the test packets have been routed through a router at a head end of a HFC network and for comparing reception parameters for the received test packets to the transmission parameters stored in the memory;

wherein the test packet generator is capable of generating the test packets with a source Internet protocol (IP) address associated with the test packet generator and a destination Internet protocol (IP) address associated with the test packet evaluator, whereby the test packets get relayed to a head end of the HFC network and routed back to the test packet evaluator.

2. The device of claim 1, wherein the test packet generator comprises a first cable modem that is external to the test device;

and

wherein the test device further comprises a cable modem interface for communicating commands and data with the test packet generator.

3. The device of claim 1, wherein the test packet generator comprises a cable modem circuit that is internal to the test device and coupled to the HFC network.

4. The device of claim 2, wherein the test packet evaluator comprises a second cable modem that is external to the test device;

and wherein the test device further comprises a cable modem interface for communicating commands and data with the test packet evaluator.

5. The device of claim 1, wherein the test packet evaluator comprises a cable modem circuit that is internal to the test device and coupled to the HFC network.

6. The device of claim 3, wherein the cable modem circuit internal to the test device also includes the test packet evaluator.

7. The device of claim 6, wherein the test packets generated by the test packet generator have a dummy IP destination address associated with a modem circuit previously provided to the cable modem circuit, whereby the cable modem circuit does not generate Address Resolution Protocol messages for the dummy IP destination address.

8. The device of claim 1, further comprising:

a test router coupled to a managed IP backbone that is coupled to the headend of the HFC network;

wherein the test packet generator is for generating a first and a second set of test packets, the first set of test packets having a destination address associated with the test evaluator and the second set of test packets having a destination address associated with the test router;

wherein the memory is for storing transmission parameters for the first and the second set of test packets; and

wherein the test evaluator is for receiving the first set of test packets after the first set of test packets have been routed through the headend of the HFC network, for receiving the second set of test packets after the second set of test packets have been routed through the test router, and for comparing reception parameters for the first and the second set of test packets with the transmission parameters stored in the memory.

9. The device of claim 7, further comprising:

a control processor coupled to the cable modem circuit having an associated IP address; and

a snoop coupled between the test packet generator and the HFC network;

wherein the snoop is for substituting the IP address that is associated with the control processor for the dummy IP destination address before the test packets are transmitted to a router at the headend of the HFC network.

10. The device of claim 9, wherein the snoop is also for intercepting the test packets returning from the headend, and substituting the source IP address with the dummy IP address, whereby the test packets appear to be from the dummy address.

11. A test device for evaluating data communication paths over a hybrid fiber cable (HFC) network comprising:

a test packet generator for generating test packets having an IP source address and a dummy IP destination address

a memory for storing transmission parameters of the test packets; and

a test packet evaluator receiving the generated test packets after the test packets have been routed through a router at a head end of a HFC network and for comparing reception parameters for the received test packets to the transmission parameters stored in the memory;

a snoop coupled between the test packet generator and the HFC network;

wherein the snoop is for substituting the IP address that is used for the IP source address for the dummy IP destination address before the test packets are transmitted to a router at the headend of the HFC network;

whereby the test packets are relayed to a head end of the HFC network and routed back to the test packet evaluator.

12. A method for evaluating data communication paths over a hybrid fiber cable (HFC) network with a test device including a test packet generator and a test packet evaluator comprising the steps of:

a) generating test packets in the test packet generator having a destination Internet protocol (IP) address associated with the test packet evaluator;

b) storing transmission parameters for the test packets in memory;

c) receiving the generated test packets at the IP address associated with the test packet evaluator after the test packets have been routed through a router at a head end of a HFC network; and

d) comparing reception parameters for the received test packets to the stored transmission parameters.

13. The method of claim 12, wherein step a) includes

communicating commands and data with a first external cable modem for generation of the test packets by the test packet generator.

14. The method of claim 12, wherein step a) includes

communicating commands and data with an internal cable modem circuit for generation of the test packets by the test packet generator.

15. The method of claim 12, wherein step c) includes

communicating commands and data with an external cable modem for reception and comparison of the test packets by the test packet evaluator.

16. The method of claim 12, wherein step c) includes

communicating commands and data with an internal cable modem for reception and comparison of the test packets by the test packet evaluator.

17. The method of claim 14, further comprising:

communicating commands and data with the internal cable modem circuit for reception and comparison of the test packets by the test packet evaluator.

18. The method of claim 17, wherein step a) includes:

generating the test packets with a source IP address and a dummy IP destination address, whereby the cable modem circuit does not generate Address Resolution Protocol messages for the dummy IP destination address.

19. The method of claim 12, wherein step a) comprises

generating a first set of test packets in the test packet generator having a destination address associated with the test evaluator;

generating a second set of test packets in the test packet generator having a destination address associated with a test router coupled to the headend of the HFC network through a managed IP backbone;

storing transmission parameters for the first and the second set of test packets;

receiving the first set of test packets in the test packet evaluator after the first set of test packets have been routed through the headend of the HFC network and back to the test evaluator;

receiving the second set of test packets in the test packet evaluator after the second set of test packets have been routed through the test router, had the destination IP address changed to the IP address of the test packet evaluator, and then routed back to the test evaluator; and

comparing reception parameters for the first and the second set of test packets with the transmission parameters stored in the memory.

20. The method of claim 18, wherein the testing device also includes a control processor connected to the cable modem circuit having an associated IP address;

and

wherein step a) also includes substituting the IP address associated with the control processor for the dummy IP destination address before the test packets are transmitted to a router at the headend of the HFC network.

21. The method of claim 20, further comprising intercepts the test packets returning from the headend, and substituting the source IP address with the dummy IP address, whereby the test packets appear to from the dummy address.

22. A method for evaluating data communication paths over a hybrid fiber cable (HFC) network with a test device including a test packet generator and a test packet evaluator comprising the steps of:

a) generating test packets in the test packet generator having an IP source address, and a destination Internet protocol (IP) address;

b) storing transmission parameters for the test packets in memory;

c) receiving the generated test packets at the IP address associated with the test packet evaluator after the test packets have been routed through a router at a head end of a HFC network; and

d) comparing reception parameters for the received test packets to the stored transmission parameters;

wherein step a) also includes substituting the IP address that is used for the IP source address for the dummy IP destination address before the test packets are transmitted to a router at the headend of the HFC network;

whereby the test packets are relayed to a head end of the HFC network and routed back to the test packet evaluator.