Overlay Packet Route Tracing With Dual TTL Hop Mapping
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional Traceroute operations are unable to identify devices over the entire path of a data packet through overlay networks due to the multiple layers and nodes involved, making it difficult to troubleshoot transmission issues.
Innovation Solution
Construct and transmit probe packets that duplicate a portion of the packet headers of data packets, using varying TTL values to trigger responses from intermediate nodes, and order these nodes based on the number of hops to trace the route through both underlay and overlay networks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional Traceroute operations are used, then routing paths in underlay networks can be identified, but paths through overlay networks cannot be traced due to multiple layers and nodes
Solution Approach 1:
The patent segments the route tracing process into two distinct phases: underlay network tracing using outer TTL values and overlay network tracing using inner TTL values. This segmentation allows each layer to be traced independently, resolving the contradiction by making the complex overlay network traceable through systematic division of the tracing mechanism into layer-specific components.
Solution Approach 2:
The patent adds a dimensional layer to traditional Traceroute by implementing dual TTL mechanisms (inner and outer TTL values) that operate at different network layers. This dimensional expansion transforms the single-layer tracing approach into a multi-layered tracing system, enabling accurate measurement of overlay network paths while maintaining underlay network visibility.
2Loss of information
If probe packets are transmitted through overlay networks, then complete path information can be obtained, but packet transmission complexity increases due to dual TTL management
Solution Approach 1:
The patent implements a nested packet structure where probe packets contain both outer envelope headers (with outer TTL for underlay routing) and inner payload headers (with inner TTL for overlay routing). This nesting allows complete path information to be captured at both network layers simultaneously, resolving the information completeness issue while managing complexity through hierarchical organization.
Solution Approach 2:
The probe packet structure is designed to serve multiple functions: it acts as a standard data packet for normal transmission while simultaneously functioning as a tracing probe with dual TTL capabilities. This multi-functionality reduces the need for separate tracing mechanisms, obtaining complete path information without proportionally increasing transmission complexity.
3Ease of operation
If traditional Traceroute is used, then simple packet transmission is maintained, but intermediate nodes in overlay networks remain unidentified
Solution Approach 1:
The patent employs periodic incrementation of inner TTL values in probe packets sent through the overlay network, similar to traditional Traceroute's outer TTL approach. This periodic action causes probe packets to expire at successive overlay network nodes, eliciting ICMP responses that identify each intermediate node. The operation remains simple and systematic while successfully identifying nodes that were previously invisible to traditional Traceroute.
Data Source
AI summary
Techniques for tracing routes taken by data packets transmitted through an overlay network are disclosed. A system uses a first TTL value for selecting a number of hops in an underlay network and a second TTL value for selecting the number of hops in the overlay network. Initially, the system increments the first TTL value with each new probe packet while holding the second TTL value at zero or one. When an overlay network node is reached by one of the probe packets, the system increments the second TTL value with each new probe packet. While incrementing the second TTL, the system holds the first TTL value at a constant value higher than the first TTL value corresponding to when the overlay network node was reached.