Method for determining the drop rate, the transit delay, and the break state of communications objects

A method of determining a mean drop rate of frames through a specific communications device which receives and forwards frames in a communications network, said method comprising:

• a. polling connected communications devices connected to the specific communications device from a network management computer (NMC) which is connected to the network,
• b. determining the fraction of poll requests from the NMC to each connected communications device for which the NMC receives replies, said fraction of poll requests being measured over a predetermined number of sampling periods,
• c. determining for each connected communications device a frame loss rate by subtracting the fraction of poll requests obtained in step b) from 1,
• d. determining a first mean value for the frame loss rates of connected communications devices which are closer to the NMC than the specific communications device,
• e. determining a second mean value for the frame loss rates of connected communications devices which are further to the NMC than the specific communications device,
• f. determining the mean drop rate for the specific communications device by calculating the difference between the first mean value and the second mean value to obtain a result and dividing the result by two,
• wherein steps c) and d) are carried out for connected communications devices which are not broken.

A method of determining a break state of a specific communications device in a communications network from a network management computer (NMC) connected to the network, said method comprising:

• a. polling communications devices in the network from the NMC,
• b. declaring said specific communications device as broken if the NMC detects at least two changes, said changes being chosen from the group comprising:
• b1. the NMC receives no replies to its polling requests directed at the specific communications device,
• b2. the NMC receives no replies to its polling requests directed at communications devices which can only be contacted by the NMC through the specific communications device
• b3. detecting no traffic flowing in any lines to or from the specific communications device,
• b4. changes in line status bits on lines connected to the specific communications device.

A method of determining a line break of a line connected to communications devices in a communications network from a network management computer (NMC) connected to the network, said method comprising:

• a. determining that the communications devices are not broken
• b. declaring the line to be broken if all the conditions in a set of conditions are met concurrently, said set of conditions being chosen from the group comprising:
• b1.
• (i) detecting zero traffic on the line,
• ((ii) detecting a change in line interface status,
• b2.
• (i) having no traffic reported on the line after a predetermined amount of time,
• (ii) detecting no changes in line status after a predetermined amount of time.

A method of determining a transit delay of frames of a first communications device in a network through the use of a network management computer (NMC), the first communications device and the NMC being connected to said network, the method comprising:

• (a) determining the transit delay of frames of a first set of devices connected between the first communications device and the NMC;
• (b) determining the transit delay of frames of a second set of devices connected to the first communications device, said second set of devices being accessible to the NMC only through the first communications device;
• (c) manipulating the results of steps (a) and (b) to determine the operating characteristics of the first communications device;
• wherein all the operating characteristics are determined relative to the NMC, wherein
• the transit delay of frames is a mean transit delay of frames,
• each of the first set of devices is closer to the NMC than the first communications device, and
• step (c) is carried out in accordance with the process:
• T(x)=((w+(x)−W−))/2
• where
• T(x):
• the mean frame transit delay for the first communications device,
• W(a):
• the mean round trip time taken between a poll request from the NMC to a communications device a and the receipt of the reply by the NMC (measured over the last N sampling periods),
• W−(x):
• The NMC's perception of the mean value of W(z) for all devices z connected to the first communications device, all devices z being in the first set of devices and are not broken,
• W+(x):
• The NMC's perception of the mean value of W(y) for all devices y connected to the first communications device, all devices y being in the second set of devices and are not broken.

A method of determining a mean drop rate of a first communications device in a network through the use of a network management computer (NMC), the first communications device and the NMC being connected to said network, the method comprising:

• (a) determining the mean drop rate of a first set of devices connected between the first communications device and the NMC;
• (b) determining the mean drop rate of a second set of devices connected to the first communications device, said second set of devices being accessible to the NMC only through the first communications device;
• (c) manipulating the results of steps (a) and (b) to determine the operating characteristics of the first communications device;
• wherein all the operating characteristics are determined relative to the NMC, wherein
• the mean drop rate is a mean drop rate of frames,
• each of the first set of devices is closer to the NMC than the first communications device, and
• step (c) is carried out in accordance with the process:
• D(x)=((L+(x)−L−(x)/2,
• and
• L(X1)=1−A(x1)
• where
• A(x1):
• the fraction of poll requests from the NMC to a device x1 for which the NMC receives replies (measured over the last M sampling periods), (wherein x must not be broken),
• C(x):
• the mean frame drop rate in the first communications device,
• L(c):
• NMC's perception of the loss rate to a device c and back,
• L−(x):
• the NMC's perception of the mean value of L(z) for all devices z connected to the first communications device, each device z being in the first set of devices and is not broken, and
• L+(x):
• the NMC's perception of the mean value of L(y) for all devices y connected to the first communications device, each device y being in the second set of devices and is not broken.

A method of determining a break state transit delay of frames of a first communications device in a network through the use of a network management computer (NMC), the first communications device and the NMC being connected to said network, the method comprising:

• (a) determining the break state of a first set of devices connected between the first communications device and the NMC;
• (b) determining the break state of a second set of devices connected to the first communications device, said second set of devices being accessible to the NMC only through the first communications device;
• (c) manipulating the results of steps (a) and (b) to determine the operating characteristics of the first communications device;
• wherein all the operating characteristics are determined relative to the NMC, wherein
• steps (a) and (b) comprises polling the first communications device along with the first and second set of devices, said polling being accomplished from the NMC and determining if the NMC receives replies to its polling requests,
• the method further includes detecting traffic flow in lines to and from the first communications device and monitoring changes in line status bits on lines connected to the first communications device,
• step (c) comprises declaring the first communications device as broken if the NMC detects at least two changes, said changes being chosen from the group comprising:
• c1. the NMC receives no replies to its polling requests directed at the first communications device,
• c2. the NMC receives no replies to its polling requests directed at the second set of devices,
• c3. detecting no traffic flowing in any lines to or from the specific communications device,
• c4. changes in line status bits on lines connected to the first communications device.

A method of determining a break state of a first communications device in a network through the use of a network management computer (NMC), the first communications device and the NMC being connected to said network, the method comprising:

• (a) determining the break state of a first set of devices connected between the first communications device and the NMC;
• (b) determining the break state of a second set of devices connected to the first communications device, said second set of devices being accessible to the NMC only through the first communications device;
• (c) manipulating the results of steps (a) and (b) to determine the operating characteristics of the first communications device;
• wherein all the operating characteristics are determined relative to the NMC, wherein
• the first communications device is a line connected between the first and second set of devices,
• steps (a) and (b) includes:
• determining that the first and second set of devices are not broken,
• detecting traffic on the first communications device,
• monitoring changes in line interface status
• step (c) comprises declaring the first communications device to be broken if all the conditions in a set of conditions are met concurrently, said set of conditions being chosen from the group comprising:
• c1.
• (i) detecting zero traffic on the first communications device
• (ii) detecting a change in line interface status,
• c2.
• (i) having no traffic reported on the first communications device after a predetermined amount of time,
• (ii) detecting no changes in line status after a predetermined amount of time.