Bi-Directional Traceroute for Hop-by-Hop Link and Node Latency
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Solution Overview
Problem
Existing traceroute mechanisms fail to provide accurate information on processing latencies introduced by intermediate nodes and delays over links between nodes, as they do not guarantee the same path in both directions, limiting network performance monitoring and root cause identification.
Innovation Solution
A bi-directional traceroute approach is implemented, where traceroute results are obtained for both forward and reverse paths, allowing computation of delay metrics for intermediate nodes and links by coordinating endpoints and using intermediate test results to drive the probing workflow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traceroute testing is performed from one endpoint to another, then metrics such as packet loss and latency are captured, but information regarding processing latencies introduced by each intermediate node and delay over each link is not provided
Solution Approach 1:
The patent segments the end-to-end network path measurement into individual hop measurements. By performing traceroute from both endpoints and collecting per-hop latency data, the system divides the overall path into discrete segments (links and nodes) that can be individually analyzed. This segmentation enables precise identification of which specific intermediate node or link contributes to delays, resolving the information loss problem.
Solution Approach 2:
The patent adds a bidirectional dimension to traditional unidirectional traceroute. By performing measurements from both endpoint A to endpoint B and endpoint B to endpoint A, the system creates two complementary measurement dimensions. This allows the calculation of round-trip latency for each hop and the derivation of one-way latency metrics, providing detailed information about intermediate node processing delays and link delays that cannot be obtained from single-direction measurements alone.
2Loss of information
If traceroute testing is performed in both directions, then more path information is obtained, but there is no guarantee that the path taken from the second endpoint back to the first endpoint will be the same as the path from the first endpoint to the second endpoint
Solution Approach 1:
The patent uses feedback from forward-path traceroute results to guide reverse-path traceroute execution. The system first performs traceroute from endpoint A to endpoint B, records the observed path and intermediate nodes, then uses this information to configure the reverse traceroute from endpoint B back to endpoint A. By feeding back the forward path information into the reverse measurement configuration, the system ensures both directions measure the same logical path, enabling reliable comparison and accurate metric derivation.
Solution Approach 2:
The patent performs preliminary traceroute testing from the first endpoint to identify the actual path taken through the network before initiating reverse-direction testing. This preliminary action reveals the sequence of intermediate nodes and links in the forward direction, which is then used to pre-configure the reverse traceroute parameters. This preliminary measurement ensures that subsequent reverse testing follows the same path, establishing a reliable baseline for comparison.
3Ease of operation
If standard traceroute mechanisms are used, then intermediate nodes are identified, but processing latencies introduced by each intermediate node and delay over each link cannot be determined
Solution Approach 1:
The patent merges forward-path and reverse-path traceroute measurements into a unified analysis framework. By combining latency data from both directions for each intermediate node and link, the system calculates composite metrics such as round-trip latency, average one-way latency, and jitter. This merging of bidirectional measurement data provides precise decomposition of total latency into node processing delays and link transmission delays, achieving high measurement precision while maintaining operational simplicity through automated computation.
Data Source
AI summary
In one implementation, a device obtains traceroute results for a forward path from a first endpoint in a network to a second endpoint in the network that indicates a plurality of intermediate nodes along the forward path. The device causes the second endpoint to perform traceroute testing with respect to the plurality of intermediate nodes, to obtain traceroute results for a reverse path between the second endpoint and the first endpoint that includes the plurality of intermediate nodes. The device computes a delay metric associated with a particular intermediate node among the plurality of intermediate nodes, based on the traceroute results for the forward path and the traceroute results for the reverse path. The device provides the delay metric for presentation via a user interface.