In-band Metadata Export at Intermediate Nodes
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Solution Overview
Problem
Existing network path tracing solutions, such as In-band/In-situ Operations, Administration, and Maintenance (IOAM) and In-Network Telemetry (INT), face challenges in large networks due to limited packet size and hardware constraints, leading to partial path information tracing and loss of IOAM data when packet drops occur, which complicates troubleshooting and debugging.
Innovation Solution
Implement a method where intermediate nodes in a network detect trigger conditions, such as insufficient space in the packet, and export accumulated metadata to a destination entity, resetting the metadata to make room for new data, allowing for partial or selective metadata export and reducing packet size constraints, while enabling continued path tracing and data collection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If unique metadata is inserted on a per-hop basis to enable path tracing, then path tracing capability is improved, but packet size increases and PMTU issues arise
Solution Approach 1:
The patent segments the path tracing function by having intermediate nodes export metadata at regular intervals or based on trigger conditions, rather than accumulating all metadata in a single packet. This divides the tracing information into multiple smaller segments that can be transmitted independently, avoiding PMTU issues while maintaining complete path tracing capability.
Solution Approach 2:
The patent extracts metadata from the main data packet at intermediate nodes and exports it separately to a collector. This separation allows the main packet to maintain a manageable size for forwarding, while the extracted metadata is transmitted independently through separate channels, resolving the conflict between complete tracing and packet size constraints.
2Loss of information
If metadata is accumulated in the packet header for each hop, then complete path information is recorded, but hardware implementation becomes complex due to write operations at varying locations
Solution Approach 1:
The patent prepares metadata export by pre-configuring intermediate nodes with collector addresses and export triggers before data transmission begins. This preliminary setup eliminates the need for complex real-time decisions about where and how to write metadata during packet forwarding, simplifying hardware implementation while maintaining complete path tracing.
Solution Approach 2:
The patent creates a copy of the metadata from the packet header at intermediate nodes and exports this copy separately. This copying approach allows the original packet to continue through the network unchanged, while the copied metadata is transmitted to collectors, significantly reducing hardware complexity by avoiding in-place modifications at varying locations.
3Loss of information
If all metadata is kept in the packet until the end, then complete path data is available, but data is lost when packet drops occur
Solution Approach 1:
The patent segments the metadata transmission by having intermediate nodes export data at intervals or upon trigger conditions. This creates multiple independent data points along the path, so if a packet drops, the collector still receives partial metadata from nodes before the drop point, preventing complete data loss and enabling troubleshooting.
Solution Approach 2:
The patent introduces intermediate nodes as mediators that collect and export metadata independently of the main data packet. These intermediary nodes act as safety points that preserve tracing information even when the primary packet is lost, enhancing reliability by creating redundant data collection paths.
Data Source
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AI summary
A method provided that is performed at one or more intermediate nodes in a path in a network. The node receives a packet having a header that includes metadata that has been accumulated as the packet travels along the path in the network. The node detects whether a trigger condition has occurred. In response to detecting that the trigger condition has occurred, the node exports, to a destination entity, at least a portion of the metadata that has been accumulated in the header so that the portion of the metadata is removed from the header after it has been exported.