Method and apparatus for monitoring a dedicated communications medium in a switched data network

• US 6,441,931 B1
• Filed: 06/30/1998
• Issued: 08/27/2002
• Est. Priority Date: 02/23/1996
• Status: Expired due to Term

• Current Assignee: RPX Clearinghouse LLC (RPX Corporation)
• Original Assignee: Nortel Networks Limited (Nortel Networks Corporation)
• Inventors: Hawe, Bill, Shvirsky, Yuval, Moskovich, Reuven
• Primary Examiner(s): PASCAL, LESLIE C
• Application Number:
  US09/108,113
• Time in Patent Office: 1,519 Days
• Field of Search: 359/110, 359/161, 359/135, 395/200, 709/224, 350/96
• US Class Current: 398/9
• CPC Class Codes: H04L 41/00 Arrangements for maintenance, administration or management of data switching networks, e.g. of packet switching networks
• CPC Class Codes: H04L 43/0817 by checking functioning
• CPC Class Codes: H04L 43/0847 Transmission error
• CPC Class Codes: H04L 43/12 Network monitoring probes

Abstract

A method and apparatus for monitoring the performance of a dedicated communications medium in a switched data networking environment wherein a probe having a bypass circuit allows promiscuous monitoring of all traffic between a switch and a network device, such as a file server, in either direction, and in full duplex mode. Additionally, the bypass circuit eliminates the requirement for a separate repeater between the switch and the network device.

Claims

1. A probe that monitors communications between a first and a second fiber optic communications medium, comprising:

a first port coupled in communication with the first fiber optic communications medium;

a second port coupled in communication with the second fiber optic communications medium;

a monitor through which the communications are passed to monitor the communications forwarded from the first port to the second port; and

an optical bypass circuit that bypasses the monitor and directly forwards the communications from the first fiber optic communications medium to the second fiber optic communications medium when power fails to the probe.

2. The probe of claim 1, wherein the optical bypass circuit is coupled in communication between the first fiber optic communications medium and the first port and between the second fiber optic communications medium and the second port to bypass the first and second ports and directly forward communications from the first fiber optic communications medium to the second fiber optic communications medium when power fails to the probe.

3. The probe of claim 2, wherein the optical bypass circuit is a dual bypass switch.

4. The probe of claim 3, wherein the first and second fiber optic communications mediums operate according to fiber distributed data interface (FDDI) protocol.

5. The probe of claim 3, wherein the first and second fiber optic communications mediums transmit communications as Ethernet formatted data packets in accordance with a carrier sense, multiple access with collision detection (CSMA/CD) protocol at a signaling rate of 100 megabits per second.

6. The probe of claim 3, wherein the first and second fiber optic communications mediums transmit communications as Ethernet formatted data packets in accordance with a carrier sense, multiple access with collision detection (CSMA/CD) protocol at a signaling rate of 1000 megabits per second.

8. The probe of claim 1, further comprising:

a first and second repeater coupled between the first port and the second port, the first repeater to receive the communications from the first port, pass them to the monitor and transmit them to the second port.

9. The probe of claim 1, further comprising:

a tap coupled between the first port and the second port, the tap to tap the communications between the first port and the second port and pass it to the monitor.

10. The probe of claim 1, wherein

the monitor monitors the communications between the first port and the second port to determine performance, error statistics, data traffic patterns and typical data flows.

11. The probe of claim 1, wherein

the optical bypass circuit is fault tolerant.

7. A probe that monitors communications between a first network device and a second network device, comprising:

a first port coupled in communication with the first network device;

a second port coupled in communication with the second network device;

a fiber optic bypass circuit that couples the first port to the second port to forward communications received from the first network device via the first port to the second network device via the second port; and

a monitor coupled to the fiber optic bypass circuit that receives communications from the fiber optic bypass circuit when power is applied to the probe so as to monitor the communications forwarded from the first port to the second port.

12. The probe of claim 7, wherein

the fiber optic bypass circuit is coupled in communication between the first network device and the first port and between the second network device and the second port to bypass the first and second ports and directly forward communications from the first network device to the second network device when power fails to the probe.

13. The probe of claim 7, wherein

the fiber optic bypass circuit is a dual bypass switch.

14. The probe of claim 7, wherein

the communication between the first port and the first network device and the second port and the second network device is in accordance with the fiber distributed data interface (FDDI) protocol.

15. The probe of claim 7, further comprising:

a repeater coupled between the first port and the second port, the repeater to receive communications from the first port, pass them to the monitor and transmit them to the second port.

16. The probe of claim 7, further comprising:

a tap coupled between the first port and the second port, the tap to tap the communications between the first port and the second port and pass it to the monitor.

17. The probe of claim 7, wherein

the monitor monitors the communications between the first port and the second port to determine performance, error statistics, data traffic patterns and typical data flows.

18. The probe of claim 7, wherein

the fiber optic bypass circuit is fault tolerant.

19. A method to monitor communication performance in a switched network between a first fiber optic communications medium and a second fiber optic communications medium, the method comprising:

providing a probe having a monitor and an optical bypass circuit between a first network device and a second network device;

monitoring the communication between the first network device and the second network device with the monitor to determine performance, error statistics, data traffic patterns and typical data flows; and

bypassing the monitoring with the optical bypass circuit and providing communication directly between the first network device and the second network device when the probe experiences a failure.

20. The method of claim 19, wherein

the failure of the probe is a power failure.

21. The method of claim 19, wherein

the failure of the probe is an operational failure.

22. The method of claim 19, further comprising:

prior to monitoring, tapping the communication between the first network device and the second network device to pass it to the monitor.

23. The method of claim 19, further comprising:

prior to monitoring, repeating the communication between the first network device and the second network device.

24. The method of claim 19, wherein

the optical bypass circuit is a dual bypass switch.

25. The method of claim 19, wherein

the communication between the first network device and the second network device is in accordance with the fiber distributed data interface (FDDI) protocol.

26. The method of claim 19, wherein

the optical bypass circuit is fault tolerant.