Packet Latency Measurement via Embedded Time Values
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Solution Overview
Problem
Current methods for measuring packet latencies in packet switching networks, such as those used in routers and bridges, are inefficient and lack comprehensive solutions for accurately determining delays across multiple devices, which is crucial for ensuring compliance with Service Level Agreements (SLAs) and optimizing network performance.
Innovation Solution
A method and apparatus where packet switching devices generate and embed time values within packets, allowing for the measurement of packet latencies by identifying and storing these values at various points within the network, enabling accurate determination of delays and compliance with SLAs through the use of shim headers and sequence numbers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If special measuring devices are connected at various points in the network to measure service levels, then measurement capability is provided, but network complexity and cost increase
Solution Approach 1:
The patent enables packet switching devices to automatically generate time values, embed them in packets, identify current time values at different positions, and calculate latencies without external measuring devices. The network infrastructure serves its own measurement needs through built-in functionality rather than requiring separate specialized equipment.
Solution Approach 2:
The patent makes packet switching devices multi-functional by enabling them to both switch packets and perform latency measurements. The same devices that route traffic also generate time values, track packet positions, and calculate latencies, eliminating the need for separate measuring devices and reducing overall network complexity.
2Measurement precision
If time values are embedded in packets to measure latencies, then measurement precision is improved, but packet processing complexity increases
Solution Approach 1:
The patent pre-embeds time values in packets at the ingress point before packets enter the switching device. This preliminary action allows subsequent latency calculations to be performed efficiently by simply comparing the pre-existing time value with the current time at egress, rather than requiring complex real-time measurement mechanisms.
Solution Approach 2:
The patent embeds time values within the packet structure itself, nesting measurement data inside the data being measured. This allows the measurement information to travel with the packet through the network without requiring separate measurement channels or external tracking systems.
3Loss of information
If latency measurements are performed across multiple packet switching devices, then network-wide performance visibility is improved, but coordination complexity between devices increases
Solution Approach 1:
The patent uses time values embedded in packets as an intermediary carrier that travels with packets across multiple devices. This intermediary mechanism allows different packet switching devices to contribute to network-wide latency measurements without requiring complex inter-device coordination protocols, as each device independently processes the embedded time information.
Data Source
AI summary
Real-time customer packet traffic is instrumented to determine measured delays between two or more points along a path actually traveled by a packet, such as within or external to one or more packet switching devices. These measurements may include delays within a packet switching device other than the ingress and egress time of a packet. These measured delays can be used to determine whether or not the performance of a packet switching device or network meets desired levels, especially for complying with a Service Level Agreement.