Switch Device Virtual Channel Stream Arbitration

The patent segments the arbitration process by introducing a second arbitration stage that operates within each virtual channel. While the first arbitration stage (output arbiter) handles different virtual channels, the second stage (per-VC arbiters) segments the arbitration for streams within the same VC by assigning unique stream identifiers and priorities, enabling differentiated handling of multiple streams over the shared connection.

The patent adds another dimension to the arbitration hierarchy by introducing stream-level arbitration within virtual channels. This creates a two-dimensional arbitration structure: the first dimension is VC-level arbitration (handling different VCs), and the second dimension is stream-level arbitration within each VC (handling multiple streams per VC). This dimensional expansion enables stream differentiation without sacrificing resource sharing.

The arbitration functionality is segmented into multiple independent arbiters: output arbiters for each output port and per-VC arbiters for each virtual channel. This segmentation allows the system to handle multiple streams within a single VC by distributing arbitration responsibilities across multiple specialized components, increasing stream capacity without proportionally increasing overall system complexity.

The per-VC arbiters serve multiple functions: they arbitrate streams within their assigned VC, enforce priority schemes, and manage stream differentiation. This multi-functionality allows a single VC configuration to support multiple arbitrable streams, increasing productivity without requiring additional VCs or significantly increasing device complexity.

The patent applies local quality by assigning different priority levels to different streams within the same virtual channel. Each stream can be configured with specific priority characteristics, allowing critical real-time streams to receive higher priority arbitration while less time-sensitive streams receive lower priority. This local differentiation maintains arbitration simplicity at the VC level while ensuring predictable real-time performance for specific streams.

The system performs preliminary action by pre-configuring priority schemes and stream identifiers before data transmission begins. This advance configuration allows the arbitration mechanism to make predictable decisions based on pre-established rules, ensuring real-time performance guarantees without requiring complex runtime analysis or negotiation.