Intra-chassis Packet Arbitration for Switching Buffer Management
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Solution Overview
Problem
Switching devices face challenges in managing buffer space for inter-chassis packet communication flows, leading to dropped packets and reduced throughput due to insufficient buffer space or excessive resource usage.
Innovation Solution
Implementing an arbitration scheme where source interface modules request permission before transmitting data packets, ensuring sufficient buffer space is available at the target interface module by using intra-chassis arbitration packets to manage communication flows, thereby reducing packet drops and optimizing buffer allocation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the switching device segments inter-chassis packets into multiple intra-chassis packets for communication over the backplane switching fabric, then the packet size limitation is resolved, but the buffer space requirements increase significantly
Solution Approach 1:
The patent implements an arbitration scheme where the source interface module requests permission from the target interface module before transmitting intra-chassis packets. The target module allocates buffer space in advance by sending an authorization packet with a buffer credit value indicating available buffer space. This preliminary allocation prevents buffer overflow and reduces the total buffer space needed by ensuring packets are only sent when buffer capacity is guaranteed.
2Device complexity
If the buffer space is insufficient to store all incoming intra-chassis packets, then the device complexity is reduced, but packet drops increase and throughput decreases
Solution Approach 1:
The patent employs a feedback mechanism where the target interface module continuously monitors its buffer status and communicates available buffer space back to the source interface module through authorization packets containing buffer credit values. The source module uses this feedback information to regulate its transmission rate, sending packets only when buffer space is available. This feedback loop prevents packet drops while maintaining optimal throughput without requiring excessive buffer space.
Data Source
AI summary
A switching device and methods thereof are disclosed. One of the methods includes an arbitration process for communicating a data payload between interface modules. A first intra-chassis packet is sent by a source interface module to the target interface module. The first intra-chassis packet represents a request for permission to transmit a data payload to the target interface. A second intra-chassis packet is received at the source interface module from the target interface module indicating whether the request has been approved. If the request is approved, the source interface module sends a third intra-chassis packet comprising at least a portion of the data payload to the target interface module.