Routing Difference Tracing via Forwarding Table Segmentation
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Solution Overview
Problem
Network performance degradation due to unintentional changes in routing tables is difficult to diagnose, as conventional routing protocols mask faults and propagate changes throughout the network, making it challenging to identify the source of differences in forwarding tables.
Innovation Solution
A method and system that compare forwarding tables between two network versions to identify changes, processing each destination sub-network prefix to determine which routers are likely the cause of differences, and assess whether these changes originated at the router or were propagated from another router, thereby isolating the root cause of observed differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional routing protocols are used to forward messages, then network connectivity is maintained, but the source of routing changes becomes difficult to identify
Solution Approach 1:
The patent segments the routing change detection process by analyzing individual forwarding table entries and isolating specific routers that exhibit changes. It divides the network into manageable segments for analysis, tracking changes at each router independently to identify the source of routing changes.
Solution Approach 2:
The patent implements preliminary actions by capturing forwarding tables at baseline and post-change states, and by having routers log their forwarding table changes with timestamps and source information before the changes propagate throughout the network. This allows the source to be identified after analysis.
2Adaptability or versatility
If routing tables are dynamically updated, then network adaptability is improved, but fault masking increases making diagnosis difficult
Solution Approach 1:
The patent implements feedback mechanisms where routers log and report their forwarding table changes, and network administrators receive feedback about routing changes through captured forwarding tables and change logs. This feedback allows diagnosis of faults while maintaining dynamic updates.
Solution Approach 2:
The patent introduces an intermediary analysis system that captures and analyzes routing changes without interfering with the normal dynamic routing operations. This intermediary layer separates the fault masking effect from the diagnostic capability, allowing both dynamic adaptability and fault detection to coexist.
3Adaptability or versatility
If multiple forwarding table entries are maintained, then routing flexibility is improved, but complexity of analyzing changes increases
Solution Approach 1:
The patent segments the analysis of multiple forwarding table entries by processing each entry individually and tracking changes at each router separately. This segmentation reduces the complexity of analyzing the overall routing table by breaking it down into manageable units.
Solution Approach 2:
The patent applies local quality analysis by examining the specific characteristics of each forwarding table entry and the local state of each router. It analyzes changes at individual routers and entries rather than treating the entire routing table as a monolithic complex structure.
Data Source
AI summary
A routing validation method and system identifies routers that are likely to be the cause of differences in forwarding tables associated with two versions of a network. Each destination sub-network prefix is processed to identify all the routers that exhibit differences in their forwarding table for this prefix. Each router exhibiting a difference is assessed to determine whether the difference may have been propagated to this router from another router. If the difference could not have been propagated from another router, this router is identified as a potential source of the observed difference. By eliminating routers that could have received the effects of the differences from another router, the task of identifying the root cause of the observed differences is substantially reduced in complexity.