Flow Control for Long-Distance Links Using Status Signals
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional flow-control schemes for long-distance data communication links require excessive buffer memory, making them costly and unsuitable for short-distance links, while modifications like SideBand Flow Control necessitate changes to the interface between media access controllers (MAC) and link-layer devices (LLD).
Innovation Solution
Implementing a network device with a media access controller that sends flow-control signals based on status signals from a link-layer device, allowing for dynamic regulation of data flow without increasing buffer size, using standard signaling and no modifications to the LLD or interface, thus supporting long-distance links with memory suitable for short-distance links.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If conventional flow-control schemes are used for long-distance links, then data can be transmitted over long distances, but excessive buffer memory is required
Solution Approach 1:
The patent applies preliminary action by having the link-layer device proactively signal its buffer status to the media access controller before the buffer becomes full. The LLD asserts status signals indicating available buffer space, allowing the MAC to regulate data transmission in advance and prevent buffer overflow without requiring excessive buffer memory at the MAC.
Solution Approach 2:
The patent implements feedback by establishing a continuous status signal mechanism where the link-layer device monitors its buffer level and sends real-time status signals to the media access controller. This feedback loop enables the MAC to adjust its data transmission rate dynamically based on the actual buffer availability at the LLD, eliminating the need for oversized buffers.
2Length of stationary object
If buffer memory is increased to accommodate long-distance links, then flow control works for long distances, but the cost increases substantially
Solution Approach 1:
By proactively signaling buffer status before overflow occurs, the system avoids the need for expensive large-capacity buffer memory in the MAC, making long-distance link support cost-effective.
Solution Approach 2:
The feedback mechanism enables efficient buffer utilization with minimal memory by continuously monitoring and adjusting data flow based on actual buffer availability, reducing the need for expensive buffer expansion.
3Length of stationary object
If a MAC with large buffer memory is designed for long-distance links, then it supports long distances, but it is too expensive for short-distance links
Solution Approach 1:
The patent achieves universality by designing a flow-control mechanism that works effectively for both short-distance and long-distance links using the same architecture. The status signal-based approach adapts to different link distances without requiring different buffer sizes, allowing a single MAC design to serve multiple applications.
Solution Approach 2:
The proactive status signaling enables the same MAC to efficiently handle varying link distances by regulating data flow based on actual buffer needs rather than predetermined buffer capacity, providing universal applicability.
4Quantity of substance
If SideBand Flow Control is used to reduce buffer requirements, then buffer memory is reduced, but modification to the MAC-LLD interface is required
Solution Approach 1:
The patent uses existing status signal mechanisms between MAC and LLD for their original purpose while adding flow-control functionality, avoiding interface modifications and maintaining compatibility with standard architectures.
Data Source
AI summary
A method, apparatus, and computer-readable media comprise storing in a first buffer data received from a network device; sending the data from the first buffer to a second buffer in response to status signals asserted by the second buffer, wherein the second buffer stores the data, and wherein the status signals asserted by the second buffer indicate an amount of the data in the second buffer; and sending flow-control signals to the network device based on the status signals asserted by the second buffer, thereby causing the network device to regulate the amount of the data sent from the network device in response to the flow-control signals.