Network Path Discovery Using Load-Balanced Probe Packets
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Solution Overview
Problem
Existing path discovery tools, such as traceroute and Paris traceroute, are ineffective in complex networks with load balancing routers, as they cannot specify the actual path taken by application packets, like HTTP, due to differences in load balancing parameters.
Innovation Solution
Generating probe packets with the same load balancing parameters as application packets and incorporating a path discovery signature in the network and transport layer headers, allowing these packets to bypass the standard protocol stack and identify the actual path taken by user application traffic.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If standard traceroute or Paris traceroute tools are used to discover network paths, then path enumeration capability is provided, but the actual path taken by application packets cannot be accurately identified in networks with load balancing routers
Solution Approach 1:
The invention creates probe packets that are copies of application packets in terms of load balancing parameters (same source/destination IP addresses, same protocol type, same source/destination ports). These probe packet copies travel through the network following the same load balancing decisions as the actual application packets, enabling accurate path discovery without disrupting normal traffic
Solution Approach 2:
The path discovery signature acts as an intermediary marker embedded in the probe packets. This signature allows intermediate routers to identify and track probe packets separately from regular application traffic, while still routing them through the same load balancing paths. The signature enables the probe packets to be recognized and processed for path discovery purposes without affecting the handling of actual application packets
2Measurement precision
If probe packets are created with different parameters than application packets for path discovery, then path tracing is enabled, but the probe packets take different paths than user application packets due to load balancing
Solution Approach 1:
The probe packets are given specific local qualities: they have the same load balancing parameters as application packets (ensuring they take the same path), but they also have a distinctive path discovery signature marker. This allows them to be treated differently only where necessary (for identification and tracking) while maintaining the same routing behavior as application packets throughout the network path
3Ease of operation
If probe packets are processed through the standard network protocol stack, then normal protocol handling is maintained, but path discovery information cannot be extracted without disrupting application packet processing
Solution Approach 1:
The path discovery signature is extracted from the probe packet and used to divert these specific packets from the standard protocol processing path. When a router or endpoint recognizes the path discovery signature, it extracts the probe packet from the normal traffic flow and routes it to a path discovery controller or handler, preventing it from being processed by the standard application protocol stack while still allowing normal application packets to flow through unchanged
Data Source
AI summary
Methods and systems for discovering a path of network traffic that travels from a source host to a destination host are disclosed. A method involves, at the source host, generating probe packets that have the same load balancing parameters as packets of an application that generates application packets for transmission from the source host to the destination host and a path discovery signature comprised of bits from at least one of the network layer header and the transport layer header. The method also involves transmitting the probe packets from the source host to the destination host. In some embodiments, the steps of the method are performed when program instructions contained in a computer-readable storage medium are executed by one or more processors.