IP Router Double-Link Failure Recovery via Backup Port Selection
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Solution Overview
Problem
Current IP networks face challenges in rapidly recovering from double-link failures without introducing high complexity or resource usage, as existing solutions either lead to service disruptions or require significant redundant bandwidth and maintenance.
Innovation Solution
The implementation of a router-based system that proactively calculates and configures primary and secondary backup ports to ensure no dead loops, allowing for fast rerouting in case of double-link failures by using a heuristic algorithm to determine backup ports and incorporating recovery distance information in packets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If routing protocols perform failure advertising and route recalculation to recover from failures, then network survivability is improved, but recovery time increases to seconds causing service disruptions
Solution Approach 1:
The patent pre-calculates and pre-configures backup ports for each router before failures occur. When a double-link failure happens, routers immediately switch to pre-configured backup ports without waiting for route recalculation, achieving fast recovery while maintaining network survivability
Solution Approach 2:
The patent implements dynamic port selection where routers can switch between primary ports and backup ports based on failure detection. The system adapts its forwarding behavior in real-time by activating pre-configured backup paths only when needed, optimizing both normal operation and failure recovery
2Speed
If lower layer protection establishes backup connections in advance to achieve fast recovery, then recovery speed is improved, but redundant bandwidth and resources are consumed
Solution Approach 1:
The patent configures backup ports at the IP layer rather than reserving full backup connections. This partial action approach provides just enough backup capability to switch paths quickly without reserving excessive redundant bandwidth, achieving fast recovery with minimal resource overhead
Solution Approach 2:
The patent changes the operational state of ports from active to standby based on failure conditions. By maintaining ports in a configurable state rather than actively using redundant bandwidth, the system achieves fast recovery capability without consuming excessive network resources during normal operation
3Loss of time
If IP fast rerouting maintains backup ports for each destination to achieve fast failure recovery, then recovery time is reduced, but device complexity increases
Solution Approach 1:
The patent segments the backup port configuration into primary backup ports and secondary backup ports with specific roles. This segmentation simplifies the decision-making process at each router by providing clear hierarchical backup options rather than requiring complex global optimization
Solution Approach 2:
The patent assigns different qualities and functions to different backup ports (primary vs secondary) based on local network conditions and failure patterns. Each router configures backup ports with specific properties appropriate to its position in the network, reducing overall system complexity through localized optimization
4Productivity
If routers use primary ports for packet forwarding to maintain efficient routing, then forwarding efficiency is improved, but service disruption occurs when double-link failures happen
Solution Approach 1:
The patent pre-configures backup ports before failures occur, so when double-link failures happen, routers can immediately switch to backup ports without service disruption. This preliminary preparation maintains both forwarding efficiency and service continuity
Solution Approach 2:
The patent prepares backup forwarding paths in advance as a cushion against potential failures. This beforehand cushioning ensures that when failures occur, the network can absorb the shock without service disruption while maintaining efficient packet forwarding through pre-positioned backup routes
Data Source
AI summary
A router in a survivable portion of a network may forward packets to a destination node even in the event of a double-link failure. For a given destination node, the router has previously been configured with a primary port, a primary backup port, and a secondary backup port. The router receives a packet addressed to the destination node within the survivable portion of the network, wherein the packet includes information indicating that the packet has encountered a failure. The router then selects one of (A) the primary port, (B) the primary backup port and (C) the secondary backup port on which to forward the received packet, such that a backup path with no dead loops is defined. The router may obtain a recovery distance of at least one of (A) the primary backup port based on a backup path to which it leads, and (B) the secondary backup port based on a backup path to which it leads, and may further obtain counter information in a packet indicative of a failure distance. In this case, the router may select a port whose recovery distance is greater than the failure distance. The router may identify a pattern of the failure. In this case, the router may make its selection using a forwarding policy associated with the identified pattern.