Path Detection via Port Mapping in IP Networks
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Solution Overview
Problem
Existing path detection mechanisms in IP networks, such as traceroute, often interfere with service flows due to differing forwarding information in detection packets and service flow packets, leading to inaccurate path identification, especially in scenarios with equal cost paths or Policy Based Routing (PBR).
Innovation Solution
A method where a forwarding device constructs detection packets with the same forwarding information as the service flow packets, ensuring consistent forwarding actions and accurate path detection by using a designated UDP port number and checksum to avoid interfering with service flows, and utilizing an external control device like an SDN controller to manage network topology and sampling for initial forwarding devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If detection packets use different port numbers from service flow packets to avoid interference, then service flow is not affected, but path detection accuracy deteriorates due to different forwarding actions
Solution Approach 1:
The patent introduces a port number mapping relationship as an intermediary mechanism. The mapping device establishes correspondence between detection packet port numbers and service flow packet port numbers, enabling the detection packets to use different port numbers (avoiding service interference) while still accurately identifying the service flow path through the mapping relationship.
2Ease of operation
If detection packets use different forwarding information from service flow packets, then detection can be performed, but path detection accuracy worsens in equal cost paths or PBR scenarios
Solution Approach 1:
The port number mapping relationship acts as an intermediary that bridges detection packets and service flow packets. It allows detection packets to have different forwarding information (enabling detection) while the mapping device uses the established correspondence to accurately determine the actual service flow path, even in complex routing scenarios like equal cost paths or PBR.
3Measurement precision
If detection packets use the same forwarding information as service flow packets, then path detection accuracy improves, but service flow interference worsens
Solution Approach 1:
The port number mapping relationship serves as an intermediary layer that decouples the forwarding information of detection packets from service flow packets. Detection packets can use different port numbers (avoiding service interference) while the mapping device translates these to the corresponding service flow port numbers to accurately trace the path, thus maintaining high detection accuracy without affecting service flows.
Data Source
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AI summary
Methods of detecting a path and forwarding devices are disclosed. In an example of the present disclosure, a first forwarding device constructs a detection packet for a service flow, wherein forwarding information in a packet head of the detection packet is same as forwarding information in a packet head of the service flow; forwards the detection packet based on the forwarding information in the packet head of the detection packet; when an error controlling packet corresponding to the detection packet is received from a second forwarding device in a set time period, the first forwarding device determines an address of the second forwarding device, returns to perform a process of constructing the detection packet for the service flow; otherwise, determines the path of the service flow based on the at least one respective address of the at least one second forwarding device.