Port Extender Ring Topology Redundancy
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Solution Overview
Problem
Existing stacking systems with IEEE 802.1BR port extender technology face significant disruptions when link or unit failures occur in PE chains, leading to multiple data ports becoming non-operational, as they are configured in linear sub-stacks rather than redundant topologies.
Innovation Solution
Implementing a ring topology for PE units connected to CB units, where one end is connected to an active CB unit and the other to a standby CB unit, allowing the CB unit to convert this physical ring into logical PE chains and automatically reconfigure in case of failures to maintain connectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If PE units are connected in a linear sub-stack configuration, then the device complexity is reduced and ease of manufacture is improved, but the reliability deteriorates when link or unit failures occur
Solution Approach 1:
The patent pre-configures standby uplink ports on PE units and standby cascade ports on CB units before failures occur. When a failure is detected, these pre-positioned standby ports are activated to restore connectivity, eliminating the need for complex dynamic reconfiguration during failures.
Solution Approach 2:
The patent segments the PE chain into multiple independent paths by configuring PE units with both active and standby uplink ports. This segmentation allows traffic to be rerouted through alternative paths when primary paths fail, improving reliability without requiring complete topology redesign.
2Reliability
If trunking is implemented between PE units and CB units, then the resistance to link failures is improved, but the resistance to unit failures remains insufficient
Solution Approach 1:
The patent introduces standby CB units as intermediary components that can take over control plane functions when active CB units fail. These standby CB units act as mediators that restore connectivity for PE units whose primary CB unit has failed, addressing the limitation of trunking which only protects against link failures.
3Reliability
If PE units are configured with standby uplink ports and CB units with standby cascade ports, then the reliability is improved against failures, but the device complexity increases
Solution Approach 1:
The patent pre-configures standby uplink ports on PE units and standby cascade ports on CB units before failures occur. When a failure is detected, these pre-positioned standby ports are activated to restore connectivity, eliminating the need for complex dynamic reconfiguration during failures.
Solution Approach 2:
The patent implements automatic failure detection and port switching mechanisms that enable the network to self-heal without manual intervention. When failures are detected, the system automatically activates standby ports and reroutes traffic, reducing the operational complexity despite the increased configuration.
Data Source
AI summary
Techniques implementing redundancy in an extended bridge comprising a controller bridge (CB) unit and a plurality of port extender (PE) units are provided. In one embodiment, the CB unit can receive join requests from the plurality of PE units and can determine, based on the join requests, whether the plurality of PE units are physically connected to the CB unit and/or other CB units in the extended bridge according to a ring topology. If the plurality of PE units are physically connected to the CB unit or the other CB units according to a ring topology, the CB unit can select a link in the ring topology as being a standby link.