Variable Packet-Size Backplanes for Switching Systems
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing switch and router systems face inefficiencies when handling variable-sized data packets, leading to increased overhead and reduced throughput due to fixed-size fabric data units (FDUs), which are not optimal for multi-service or multi-protocol applications.
Innovation Solution
Implementing a system that uses variably-sized FDUs, with sizes ranging from a minimum to a maximum, and distributed control among ingress and egress elements, allowing for efficient forwarding of data packets independent of packet sizes, and employing scheduling methods like weighted-fair and deficit scheduling to manage resource allocation and latency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If fixed-size fabric data units (FDUs) are used for switching, then simplified fabric control and synchronous allocation are achieved, but overhead increases and throughput decreases when handling variable-sized data packets
Solution Approach 1:
The patent applies dynamics by making the FDU size variable rather than fixed. The system dynamically adjusts FDU payload size based on the actual data packet size being transmitted, allowing the switching fabric to efficiently handle both small and large packets without excessive overhead or segmentation, thereby resolving the contradiction between control simplicity and switching throughput.
Solution Approach 2:
The patent changes the parameter of FDU size from a fixed value to a variable parameter that adapts to the data packet size. By allowing the payload size to vary while maintaining a fixed header structure, the system achieves both simplified control (through standardized FDU format) and improved throughput (by eliminating wasted space in fixed-size units).
2Reliability
If short fixed-size FDUs are used, then quality of service is improved by limiting interference, but overhead increases due to packet segmentation
Solution Approach 1:
The system dynamically adjusts FDU size to match the data packet size, eliminating the need for excessive segmentation when packets are small. This dynamic sizing maintains QoS by limiting interference through controlled transmission units while reducing overhead by avoiding segmentation of packets that don't require it.
Solution Approach 2:
By changing the FDU payload size parameter to be variable rather than fixed, the system optimizes the balance between QoS maintenance and overhead reduction. The header size remains fixed for control simplicity, while the payload size adapts to minimize segmentation overhead.
3Loss of substance
If longer fixed-size FDUs are used, then FDU-header overhead is reduced, but packet segmentation overhead increases and latency increases
Solution Approach 1:
The system dynamically selects appropriate FDU sizes based on packet characteristics, avoiding the need for very long fixed-size FDUs. This dynamic approach reduces latency by transmitting smaller packets in appropriately sized FDUs without unnecessary segmentation, while still maintaining low header overhead through efficient payload utilization.
4Device complexity
If fixed-size FDUs are used in multi-service applications, then simplified switching is achieved, but efficiency decreases due to overhead from variable packet sizes
Solution Approach 1:
The patent implements dynamic FDU sizing that adapts to different packet sizes in multi-service applications. This maintains the simplicity of the switching mechanism through standardized FDU formatting while dramatically improving efficiency by eliminating the overhead associated with forcing variable-sized packets into fixed-size units.
Data Source
AI summary
The present invention provides switches and routers, preferably with fully-connected mesh fabrics, that transmit data through the switch fabric in variable-size data units. Variable-size data units allow switches and routers to provide throughputs close to hardware capabilities, eliminating the need for over-capacity hardware in the switch fabric and other components. Along with variably-size data units, preferred embodiments of this invention include scheduling methods that provide fair allocation of pre-determined bandwidths to different protocols, to different classes of service within protocols, and to different resources within the switch by use of certain weighted, fair scheduling methods. The switches and routers of this invention are particularly directed to multi-protocol, high-throughput communication applications, but may have wide applicability in systems generally where data packets are switched or routed.