Scheduler Module for Crossbar Packet Transfer
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Solution Overview
Problem
Current network access systems face inefficiencies in packet transmission between interface control modules, particularly in scheduling and transferring packets through crossbar modules, which can lead to delays and increased memory requirements due to reordering and reassembly of packets.
Innovation Solution
The system incorporates line cards with interface control modules and crossbar modules, where a scheduler module allocates links and generates acknowledgement signals to route packets efficiently, preventing overflow in crossbar module queues and minimizing reordering by transferring full packets, and includes features like multi-stage scheduling and asymmetric forward error correction to optimize packet transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If packets are transferred through crossbar modules without scheduling, then transmission speed is improved, but packet reordering and reassembly are required leading to increased memory requirements and delays
Solution Approach 1:
The scheduler module performs preliminary scheduling of packets before they are transferred through crossbar modules. By pre-determining the transmission path and timing for each packet, the system avoids the need for reordering and reassembly at the destination, thereby reducing memory requirements and transmission delays while maintaining high transmission speed
2Device complexity
If crossbar module queues are not managed, then device complexity is reduced, but packet overflow occurs leading to loss of information
Solution Approach 1:
The scheduler module implements a feedback mechanism that continuously monitors the status of crossbar module queues. Based on this feedback, the scheduler dynamically adjusts packet transmission timing and routing to prevent queue overflow, thereby avoiding packet loss without requiring complex queue management structures at each crossbar module
3Reliability
If multiple crossbar modules are used for packet transfer, then transmission reliability is improved, but scheduling complexity increases leading to device complexity increase
Solution Approach 1:
The invention combines the scheduling function with the crossbar module control logic into an integrated scheduler module. This merging of functions allows multiple crossbar modules to be coordinated for reliable packet transfer while avoiding the complexity of separate scheduling systems, as the unified module manages all crossbar operations through a single control architecture
Data Source
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AI summary
An access system includes line cards. The line cards include first and second line cards. The first line card receives a first packet and includes a first interface control module that generates a first request signal to transfer the first packet. The first request signal includes an identifier of a second interface control module in the second line card. Crossbar modules are separate from the line cards and include first and second crossbar modules. The first crossbar module includes a first scheduler module. The second crossbar module transfers packets between a pair of the line cards. The packets include the first packet. The first scheduler module is separate from the line cards and, based on the first request signal, schedules the transfer of the packets from the first interface control module, through the second crossbar module, and to the second interface control module.