Egress Port Loopback for Fast Packet Rerouting
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Solution Overview
Problem
Existing fast rerouting methods in communication networks are inefficient as they impose a heavy burden on nodes and take longer to switch traffic to detour paths upon failure, especially with multiple flows, leading to significant degradation in service quality and potential upper network layer failures due to slow recovery.
Innovation Solution
A network device with multiple ports that selects an egress port for packets and forwards them to a usable port, using primary or detour forwarding rules, and can loop packets back internally to switch efficiently to a detour path without knowledge of flow associations, allowing for quick rerouting independent of the number of flows.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing fast rerouting methods are used, then protection paths are established for link or node failure, but the switching time to detour paths is long especially with multiple flows
Solution Approach 1:
The patent pre-establishes detour paths and configures loopback mechanisms at egress ports before failures occur. When a failure is detected, packets are immediately redirected through the loopback path without requiring complex real-time calculations or flow association knowledge, enabling sub-50ms switching times.
Solution Approach 2:
The invention segments the forwarding decision process by separating primary path forwarding from detour path activation. The loopback mechanism creates an independent detour path segment that can be activated without affecting other flows, allowing parallel processing of multiple flows during failure recovery.
2Productivity
If existing fast rerouting methods process multiple flows individually, then each flow can be routed, but the processing burden on nodes increases significantly
Solution Approach 1:
The egress port loopback mechanism serves as a universal solution for all flows destined through a failed egress port. Instead of implementing flow-specific detour logic, the loopback provides a single multi-functional path that handles all affected flows uniformly, reducing node processing complexity while maintaining full forwarding capability.
3Reliability
If traditional rerouting methods are used, then failure recovery is achieved, but service quality degrades significantly during the recovery period
Solution Approach 1:
The loopback mechanism enables packets to skip the failed egress port and downstream failure point by redirecting them through alternative egress ports. This immediate bypass eliminates the service quality degradation period, maintaining packet forwarding continuity with minimal latency impact during failure recovery.
Data Source
AI summary
A network device includes processing circuitry and multiple ports. The multiple ports are configured to connect to a communication network. The processing circuitry is configured to select a first port among the multiple ports to serve as an egress port for a packet, and to forward the packet to the first port, irrespective of whether or not the first port is usable as the egress port. The processing circuitry is further configured to, when the first port is usable as the egress port, transmit the packet to the communication network via the first port, and when the first port is unusable as the egress port, forward the packet from the first port to a second port among the multiple ports and transmit the packet to the communication network via the second port.