Service Flow Path Detection via Packet Header Copying
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Solution Overview
Problem
In the traceroute mechanism for IP network path detection, the forwarding behavior of detection packets differs from that of service flow packets, leading to an inconsistent path detection that does not accurately represent the actual service flow path.
Innovation Solution
Constructing detection packets to simulate the header of the actual service flow, ensuring that each forwarding device forwards the detection packet based on the same forwarding information as the service flow, thereby maintaining consistent forwarding behavior and accurately determining the service flow path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If detection packets use different port numbers from service flow packets to avoid affecting service flow, then service flow is protected from interference, but the detected path becomes inconsistent with the actual service flow path
Solution Approach 1:
The patent creates a copy of the service flow packet's header information (including source IP, destination IP, protocol type, and port numbers) to construct the detection packet. This copying ensures the detection packet follows the exact same forwarding path as the actual service flow, while the service flow itself remains unaffected because the detection uses copied parameters rather than modifying the original service packets.
2Measurement precision
If detection packets use the same forwarding information as service flow packets, then path detection accuracy improves, but the detection packet may interfere with service flow
Solution Approach 1:
Instead of using the same actual service flow packets for detection (which would cause interference), the patent copies the forwarding information (IP addresses, protocol type, port numbers) from the service flow packets to create separate detection packets. This copying approach allows accurate path tracing while keeping the original service flow intact and unaffected.
Solution Approach 2:
The patent introduces an intermediary mechanism where the detection packet uses copied forwarding information as a mediator between the service flow and the path detection process. This intermediary approach allows the detection system to obtain accurate path information without directly interfering with the actual service flow packets.
3Ease of operation
If detection packets use different forwarding information from service flow packets, then service flow is protected, but the detected path does not reflect the actual service flow path
Solution Approach 1:
The patent copies the essential forwarding information (source IP, destination IP, protocol type, port numbers) from the service flow packets to construct detection packets. This copying preserves the path consistency information needed for accurate detection while protecting the actual service flow from interference, as the detection uses replicated rather than original packet data.
Data Source
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AI summary
Methods for detecting a path, a forwarding device and a machine-readable storage medium are provided. In an example, a first forwarding device receives a first detection packet sent from a previous hop forwarding device on a path of a designated service flow and used for detecting the path of the designated service flow; the first forwarding device obtains a second detection packet by adding a device address of the first forwarding device to a payload of the first detection packet; the first forwarding device forwards the second detection packet to a next hop forwarding device on the path of the designated service flow based on forwarding information in a header of the second detection packet; and the first forwarding device sends to a SDN controller a forwarding error message in which a device address of at least one forwarding device in the payload of the first detection packet is carried.