Dynamic DIS Priority Change for IS-IS Network Resilience
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Solution Overview
Problem
In IS-IS-based networks, the lack of control plane redundancy leads to data plane traffic loss due to underlay failures, causing connectivity issues and disruptions in network traffic.
Innovation Solution
Implementing a method to dynamically change the designated intermediate system (DIS) within the network by monitoring connectivity and adjacencies between nodes, using a DIS priority change algorithm to ensure seamless transition and maintain connectivity, even in the presence of underlay failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If IS-IS protocol is used for network connectivity, then routing efficiency is improved, but control plane redundancy is lost leading to traffic loss during underlay failures
Solution Approach 1:
The system performs preliminary actions by pre-establishing multiple potential DIS candidates and their adjacency relationships before failures occur. When a failure is detected, the system can immediately switch to a pre-identified backup DIS without waiting for election processes, thus preventing traffic loss while maintaining routing efficiency.
Solution Approach 2:
The invention implements beforehand cushioning by creating redundant adjacency relationships and pre-configuring backup DIS nodes. This cushioning mechanism ensures that when underlay failures occur, the network has pre-prepared alternative paths and control plane redundancy to prevent traffic loss, resolving the contradiction between routing efficiency and reliability.
2Adaptability or versatility
If DIS election is performed dynamically, then adaptability to network changes is improved, but connectivity disruptions occur during transition
Solution Approach 1:
The system performs preliminary actions by pre-identifying backup DIS candidates and establishing their adjacency relationships in advance. When a DIS failure occurs, the system can immediately switch to the pre-identified backup without waiting for dynamic election processes, thus avoiding connectivity disruptions while maintaining adaptability.
Solution Approach 2:
The invention implements feedback mechanisms where network nodes continuously monitor DIS availability and adjacency status. When failures are detected, the feedback loop triggers immediate switchover to backup DIS nodes, ensuring both adaptability to network changes and connectivity stability during transitions.
3Reliability
If multiple adjacencies are maintained, then network resilience is improved, but device complexity increases
Solution Approach 1:
The system segments the adjacency management function by separating primary DIS operations from backup DIS operations. This segmentation allows the network to maintain multiple adjacencies for resilience while managing complexity through structured organization of primary and backup relationships, reducing the burden on individual devices.
Solution Approach 2:
The invention introduces intermediary mechanisms where backup DIS nodes serve as intermediaries that stand ready to take over primary DIS functions. This intermediary approach allows multiple adjacencies to be maintained for resilience while the backup nodes act as mediators that simplify the overall system management by providing predetermined failover paths.
Data Source
AI summary
A communication pathway between a plurality of network nodes within a network is established. A DIS election operation is executed to determine a first network node among the plurality of network nodes as the DIS for the network and creating a first pseudo node for the first network node, and with each network node of the plurality of network nodes, determining whether the connectivity between the first network node and the other network nodes of the plurality of network nodes within the network is in a synchronous state with the adjacencies with the other network nodes of the plurality of network nodes within the network.