Shared Multi-Bank Memory for Packet Switching Blocking
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Solution Overview
Problem
Current shared memory architectures in packet switches are not fast enough to handle high data transfer rates required for modern networks, such as local area networks (LANs) and wide area networks (WANs), and are prone to blocking issues.
Innovation Solution
The method involves storing sequential data units of a data packet in contiguous banks of a shared memory and maintaining a buffer usage count to manage memory efficiently, allowing for multicasting and reducing blocking by optimizing buffer usage and access control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a shared memory architecture is used for packet switching, then memory sharing and port access control are simplified, but the data transfer speed is insufficient to handle high data rates required for modern networks
Solution Approach 1:
The shared memory is divided into multiple banks (first bank, second bank, third bank, fourth bank) that can be accessed simultaneously by different ports. This segmentation allows parallel data transfer operations across multiple memory banks, achieving high data rates while maintaining the shared memory architecture's simplicity for port access control.
2Ease of operation
If a shared memory architecture is used, then port access control is simplified, but blocking occurs when multiple ports attempt to access memory simultaneously
Solution Approach 1:
The memory is segmented into multiple banks with independent access paths. When multiple ports attempt to access memory simultaneously, they can access different banks without blocking each other, eliminating the blocking problem while maintaining simplified port access control through the shared memory architecture.
Solution Approach 2:
The patent introduces a bank dimension to the memory access structure. Instead of a single memory access path, multiple ports can access different banks in parallel, adding a dimensional aspect to memory access that resolves the blocking issue while preserving the ease of control.
3Quantity of substance
If sequential data units are stored in contiguous banks, then buffer memory utilization is enhanced, but memory management complexity increases
Solution Approach 1:
The system pre-establishes contiguous bank allocation for sequential data units before data transfer operations. This preliminary organization of memory spaces allows for efficient buffer utilization during actual data transfer, reducing the need for complex real-time memory management decisions.
Data Source
AI summary
Generally, a method and apparatus are disclosed that store sequential data units of a data packet received at an input port in contiguous banks of a buffer in a shared memory, thereby obviating any need for storing linkage information between data units. Data packets can extend through multiple buffers (next-buffer linkage information is much more efficient than next-data-unit linkage information). According to another aspect of the invention, buffer memory utilization can be further enhanced by storing multiple packets in a single buffer. For each buffer, a buffer usage count is stored that indicates the sum (over all packets represented in the buffer) of the number of output ports toward which each of the packets is destined.