Transmission Delay Difference Determination Using Order Indicators
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Solution Overview
Problem
Existing methods for determining transmission delays in protocol data units require clock frequency-locking between network elements and transmission time information, which are not always feasible in telecommunications applications, leading to increased buffering needs due to varying delays and order changes in data packets.
Innovation Solution
A method that uses order indicators to determine the sequential order of protocol data units, allowing calculation of transmission delay differences without requiring clock frequency-locking or transmission time information, and downgrades quality classifications for affected ingress ports to mitigate delays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If transmission delay differences are determined using prior-art methods requiring clock frequency-locking and transmission time information, then measurement precision can be achieved, but device complexity and ease of operation deteriorate due to synchronization requirements
Solution Approach 1:
The patent extracts the transmission delay measurement problem from the complex clock synchronization requirement. Instead of requiring synchronized clocks between source and destination network elements, the invention uses only local clock information at the destination element to determine transmission delay differences by comparing reception time stamps with sequentially transmitted protocol data units.
Solution Approach 2:
The patent introduces reception time stamps as an intermediary mechanism. These time stamps are attached to protocol data units at the source and read at the destination, serving as a mediator that enables delay measurement without requiring direct clock synchronization between network elements. The time stamps act as portable time references that eliminate the need for synchronized clocks.
2Reliability
If buffering is increased to handle varying transmission delays and order changes, then reliability of data delivery is improved, but loss of time increases due to additional buffering delay
Solution Approach 1:
The patent applies preliminary action by determining transmission delay differences proactively using the measured values from sequentially transmitted protocol data units. This allows the network element to anticipate and prepare for potential order changes and delay variations before they affect data delivery, enabling more efficient buffering strategies that reduce overall buffering time while maintaining reliability.
3Productivity
If routing protocols are configured to avoid high-delay areas or downgrade quality classifications, then productivity improves by reducing buffering needs, but measurement precision must be maintained to identify appropriate routes
Solution Approach 1:
The patent enables self-service by allowing each destination network element to autonomously determine transmission delay differences for its incoming protocol data units using locally available information. This distributed measurement approach provides precise delay data at each network element, enabling routing protocols to make informed decisions about path selection and quality classification without centralized control, thereby improving overall network productivity while maintaining measurement accuracy.
Data Source
AI summary
The invention relates to determining mutual differences of transmission delays experienced by protocol data units transmitted in a communications network. This invention is based on a surprising discovery that the time difference between the receiving moments of protocol data units the temporal receiving order of which deviates from their temporal transmitting order represents the smallest possible difference between the transmission delays experienced by these protocol data units. In a method according to the invention it is determined, based on an order indicator associated with a protocol data unit received at an earlier point of time and an order indicator associated with a protocol data unit received at a later point of time, whether the mutual order of the protocol data units changed during transmission. If the mutual order has changed, the time difference between the receiving moments of the protocol data units is calculated, which time difference represents the smallest possible difference between the transmission delays experienced by these protocol data units.