Logical Topology Number for Forwarding Database Consistency
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Solution Overview
Problem
Current communication networks face inefficiencies in managing logical topology changes, as flushing forwarding database entries can be time-consuming and often results in unnecessary deletions, failing to account for unaffected ports and links.
Innovation Solution
The method involves maintaining a logical topology number (LTN) for each logical topology, identifying changes, generating a topology change message, and comparing LTNs to invalidate only necessary entries in the forwarding database, with intelligent broadcasting to update entries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If forwarding entries are flushed in response to network topology change, then forwarding database consistency is improved, but convergence time increases and network productivity decreases
Solution Approach 1:
The patent segments the forwarding database into multiple tables (first forwarding table and second forwarding table) that can be independently updated. When a topology change occurs, only the affected table is flushed while the other remains intact, allowing continuous forwarding operations and reducing convergence time compared to flushing the entire database at once.
Solution Approach 2:
The patent performs preliminary actions by maintaining both forwarding tables in advance and preparing for seamless switching. The system pre-configures the alternative forwarding table so that when a flush is needed, the switch can immediately use the pre-prepared table without waiting for relearning, thus reducing convergence time.
2Reliability
If forwarding entries are flushed in response to network topology change, then outdated entries are removed, but unnecessary deletions increase and network productivity decreases
Solution Approach 1:
The patent applies local quality by selectively flushing only the specific forwarding table that contains outdated entries related to the affected port, while leaving other tables intact. This targeted approach removes only necessary entries and preserves valid forwarding information, maintaining network productivity during topology changes.
3Reliability
If software selectively removes entries one-by-one from the database, then unnecessary deletions are reduced, but processing time increases and convergence time increases
Solution Approach 1:
The patent segments the forwarding database into multiple independently manageable tables. Instead of selectively removing entries one-by-one from a single large database, the system flushes only the affected segment (table) in response to topology changes, significantly reducing processing time and convergence time while maintaining consistency.
Data Source
AI summary
The present disclosure relates to managing a logical topology change in a network. The entries of the forwarding database are flushed intelligently without arbitrarily removing the forwarding database resulting in flooding. In one embodiment, a logical topology number (LTN) is maintained by all the interfaces and the forwarding database in the logical topology. In case of any change in the network topology, the LTN of the interfaces affected by the topology change is changed. Further, while sending a frame, LTN of the forwarding database entry for a destination address is compared with LTN of the logical topology. In case of mismatch, the entry is invalidated and the frame is flooded to all other ports for entering new entries into the database. LTN of the forwarding database entry for a source address is compared with the LTN of the logical topology.