Method for determining the delay and jitter in communication between objects in a connected network
First Claim
1. A method of determining a total processing overhead delay between a first node and a second node in a network connected to both the first node and the second node, the method comprising:
- a) determining interim transit delays processing overhead delays between adjacent nodes in a communications path between the start node and the end node including the following steps;
a1) sending a first signal from a common node to the first node;
a2) receiving a first response signal at the common node from the first node in response to the first signal;
a3) determining a first round trip time, the first round trip time being a time elapsed between steps a) and b);
a4) sending a second signal from the common node to the second node;
a5) receiving a second response signal at the common node from the second node in response to the second signal;
a6) determining a second round trip time, the second round trip time being a time elapsed between steps d) and e); and
a7) calculating the transit delay between the first node and the second node according to the formula
D(X,Y)=|R(NMC,X)−
R(NMC,Y)|/2whereD(X,Y) is the transit delay between first node X and second node Y;
R(NMC,X) is the first round trip time;
R(NMC,Y) is the second round trip time; and
NMC is the common node;
a8) subtracting a previously determined minimum transit delay between the first node and the second node with the transit delay between the first node and the second node; and
b) calculating the total transit overhead processing delay between the start node and the end node by adding up the interim transit processing overhead delays.
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Abstract
Methods which determine network performance by determining not only the transit delay between nodes in a network but also the variance, or jitter, of such transit delays. A common node, usually a network management computer (NMC), sends out a signal to a first node of interest and measures the time before it receives an acknowledgment from the first node. The NMC then sends out a similar signal to a second node of interest and similarly measures the time required to receive an acknowledgment. Based on these two measurements, the transit delay between the first and second nodes can be calculated if the first node lies on the path between the NMC and the second node or vice versa. For a multiple node communications path, the total transit delay between any two nodes is the sum total of the transit delays between adjacent nodes lying on the path. In the case of meshed networks, where a path to a node may be ambiguous, additional measurement nodes strategically positioned in the network can be used such a way that the transit delay between any adjacent pair of nodes can be calculated unambiguously from at least one of these measurement nodes, i.e., the portion of the network being measured will be reduced to a hierarchical one with respect to at least one of the measurement nodes.
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Citations
16 Claims
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1. A method of determining a total processing overhead delay between a first node and a second node in a network connected to both the first node and the second node, the method comprising:
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a) determining interim transit delays processing overhead delays between adjacent nodes in a communications path between the start node and the end node including the following steps; a1) sending a first signal from a common node to the first node; a2) receiving a first response signal at the common node from the first node in response to the first signal; a3) determining a first round trip time, the first round trip time being a time elapsed between steps a) and b); a4) sending a second signal from the common node to the second node; a5) receiving a second response signal at the common node from the second node in response to the second signal; a6) determining a second round trip time, the second round trip time being a time elapsed between steps d) and e); and a7) calculating the transit delay between the first node and the second node according to the formula
D(X,Y)=|R(NMC,X)−
R(NMC,Y)|/2where D(X,Y) is the transit delay between first node X and second node Y; R(NMC,X) is the first round trip time; R(NMC,Y) is the second round trip time; and NMC is the common node; a8) subtracting a previously determined minimum transit delay between the first node and the second node with the transit delay between the first node and the second node; and b) calculating the total transit overhead processing delay between the start node and the end node by adding up the interim transit processing overhead delays. - View Dependent Claims (2, 3)
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4. A method of determining the quality of communications between two nodes in a network, the method comprising:
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a) measuring a transit delay between the two nodes at different times resulting in a plurality of transit delay measurements; b) calculating a jitter among the plurality of time delay measurements based on measuring a variance of the plurality of transit delay measurements; and c) determining if the jitter exceeds a predetermined threshold value. - View Dependent Claims (5, 6, 7, 8, 9)
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10. A method of determining a jitter between two transit delay measurements between two nodes, the method comprising:
calculating the jitter based on
J(A,D,t)=D(A,D,t2)−
D(A,D,t1))where J(A,D,t) is the jitter between the two transit delay measurements based on measuring a variance of the two transit delay measurements; D(A,D,t1) is one of the two transit delay measurements taken at time t1; D(A,D,t2) is the other of the two transit delay measurements taken at time t2; and A and D are the two nodes between which the transit delay is measured. - View Dependent Claims (11, 12)
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13. A method of determining a jitter between a plurality of transit delay measurements between two nodes, the method comprising:
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calculating the jitter based on
whereJ(A,B) is the jitter between the plurality of transit delay measurements; D(A,B,i) is the ith transit delay measurement among the plurality of transit delay measurements; and M is the number of transit delay measurements. - View Dependent Claims (14, 15)
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16. A method of determining a signal processing time in a node, the method comprising:
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a) determining at least one round trip delay time of a transmission between a node A and a node K; b) determining a round trip delay time of a transmission between a node B and a node K; c) determining a lowest recorded value for the round trip delay time between node A and node K; d) calculating the signal processing time through node A according to;
P(A)=R(K,B)−
minimum (R(K,A))
whereP(A) is the signal processing time through node A; R(K,B) is a round trip delay time between node B and node K; and (minimum (R(K,A)) is the lowest recorded value for the round trip delay time between node A and node K.
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Specification