VLAN-Aware Packet Relay Congestion Control
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Solution Overview
Problem
Conventional relay apparatuses cannot perform congestion control for each virtual network, as they discard packets of a predetermined priority regardless of the virtual network they belong to, failing to consider the differences between virtual networks.
Innovation Solution
A relay apparatus with multiple queues associated with a combination of priority and VLAN number, featuring a queue-number storage unit, an accumulated-amount storage unit, and a threshold storage unit, which determines the storage queue for incoming packets and discards them based on the total packet accumulated amount and threshold specific to each queue, allowing congestion control for each virtual network.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If congestion control is performed by discarding packets when the amount of received packets of a predetermined priority exceeds a threshold, then packet priority management is improved, but congestion control cannot be performed for each virtual network and packets are discarded regardless of which virtual network they belong to
Solution Approach 1:
The patent segments the congestion control mechanism by introducing VLAN identifiers to differentiate between virtual networks. Instead of a single congestion control policy for all packets, the system now maintains separate congestion control states and thresholds for each VLAN, allowing independent congestion management per virtual network while preserving priority-based packet handling.
Solution Approach 2:
The patent applies local quality by making congestion control parameters (thresholds, accumulation amounts) specific to each VLAN and priority combination. Each virtual network can have customized congestion control characteristics tailored to its requirements, rather than applying a uniform policy across all networks.
2Adaptability or versatility
If multiple queues are provided in association with a combination of priority and VLAN number, then congestion control for each virtual network is enabled, but device complexity increases due to additional storage units and determination logic
Solution Approach 1:
The patent achieves universality by designing a multi-dimensional queue identification system where a single queue structure serves multiple VLANs and priority levels. The queue number is constructed by combining VLAN ID and priority bits, allowing the same physical queue infrastructure to handle traffic from different virtual networks with different priorities through logical differentiation rather than requiring separate physical queues for each combination.
Solution Approach 2:
The patent merges the VLAN identification and priority identification into a unified queue selection mechanism. Instead of maintaining separate queue management systems for VLANs and priorities, the system combines these dimensions into a single queue number that indexes into a shared queue array, reducing overall system complexity.
3Reliability
If packets are discarded based on total packet accumulated amount and threshold for each queue, then effective congestion control is achieved, but more storage units are required to track accumulated amounts per priority
Solution Approach 1:
The patent transitions from tracking packet accumulation per individual queue to tracking accumulation per priority level across all VLANs. By changing the dimension of aggregation from (VLAN, priority) pairs to priority-only, the system reduces the number of storage locations needed while still enabling effective congestion control through VLAN-specific threshold comparisons.
Data Source
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AI summary
A relay apparatus for use with virtual networks (VLANs). Each transmission port module (12a, 12b, 12c) includes a plurality of queues (150-0, 150-1) in association with combinations of a priority and a VLAN number. An accumulated-amount storage unit (157) stores a total size of packets accumulated in queues associated with the same priority. A threshold storage unit (158) stores a threshold of a total packet accumulated amount for each queue. When a packet is received, whether to discard the packet is determined based on a total packet accumulated amount stored in the accumulated-amount storage unit (157) in association with a priority set for the packet and the threshold stored in the threshold storage unit (158) in association with a storage-destination queue of the packet.