Visibility Packet Sampling for Packet Drop and Queue Delay Insight
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Solution Overview
Problem
Network devices, particularly in complex topologies like modern data centers, suffer from limited visibility into packet loss and other issues such as silent packet drops, silent black holes, and inflated latency, leading to inefficient and slower network communications.
Innovation Solution
Implement marker-based delay tracking and visibility sampling techniques to generate visibility packets that provide insight into queue delays and packet drops, using samplers to limit the number of visibility packets and enhance network device performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If visibility packets are generated for every packet drop and delay event, then network visibility and diagnostic capability are improved, but device performance and resource utilization deteriorate due to excessive packet processing overhead
Solution Approach 1:
The patent implements sampling-based visibility packet generation, where only a subset of packet drop and delay events triggers visibility packet creation. The sampler selectively chooses events based on configurable sampling rates, providing sufficient network visibility information while avoiding the performance degradation that would result from generating visibility packets for every single event.
2Measurement precision
If detailed tracking of every packet through markers is implemented, then measurement precision of queue delays is improved, but device complexity and processing overhead increase
Solution Approach 1:
The patent applies marker-based delay tracking selectively through sampling. Instead of inserting markers into every packet, the system uses samplers to choose specific packets for marker insertion based on configurable rates. This provides adequate measurement precision for diagnostic purposes while significantly reducing the complexity and overhead associated with tracking every packet individually.
Data Source
AI summary
In response to certain events in a network device, visibility packets may be generated. A visibility packet may be or comprise at least a portion of a packet that is in some way associated with the event, such as a packet that was dropped as a result of an event, or that was in a queue at the time of an event related to that queue. A visibility packet may be tagged or otherwise indicated as a visibility packet. The network device may include one or more duplicate flow suppression samplers through which visibility packets are routed on their way to a visibility queue, visibility subsystem, and/or out of the network device. The samplers allow only a limited sample of the visibility packets that they receive to pass through the sampler, essentially acting as a filter to reduce the amount of visibility packets that will be processed.