Node Reachability in Multi-Level ASON Networks
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Solution Overview
Problem
In multi-level ASON networks, determining node reachability and identifying internal versus external links is challenging due to the lack of comprehensive network topology information across control domains, limiting dynamic and flexible connection establishment.
Innovation Solution
The method involves node address aggregation and dissemination of aggregation addresses through a routing protocol, using a one-to-one correspondence between control domains and routing controllers to form reachable address lists, allowing nodes to determine reachability and link types by searching for corresponding RC IDs within the same control domain.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the ASON network is divided into multiple control domains to manage network expansion, then the network scalability is improved, but the node reachability determination becomes more difficult due to limited topology information visibility
Solution Approach 1:
The network is divided into multiple control domains with hierarchical levels, where each domain manages a portion of the network. This segmentation allows the network to scale by adding more domains without requiring any single node to maintain complete topology information of the entire network, thus resolving the contradiction between network scale and reachability determination difficulty.
Solution Approach 2:
A hierarchical control domain structure is implemented where lower-level control domains are nested within higher-level control domains. Each level aggregates topology information from subordinate levels, creating a nested information structure that enables reachability determination across the entire network while maintaining manageable domain sizes.
2Ease of operation
If hierarchical routing is used to establish connections across control domains, then the network manageability is improved, but the link identification complexity increases due to abstract node representations
Solution Approach 1:
Routing controllers are introduced as intermediary entities between control domains. These RCs manage the abstract node representations and provide standardized interfaces for link identification, simplifying the interaction between domains while maintaining the hierarchical routing structure. The RCs translate between abstract domain-level views and concrete link-level details.
3Measurement precision
If complete network topology information is maintained at each node to enable reachability determination, then the node reachability accuracy is improved, but the information storage and processing requirements increase significantly
Solution Approach 1:
Each node maintains topology information appropriate to its local control domain and hierarchical level, rather than complete network-wide topology. The hierarchical structure ensures that nodes only store and process topology data relevant to their domain, reducing information volume while maintaining sufficient accuracy for reachability determination within and across domains.
Data Source
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AI summary
The present invention discloses a method for identifying node reachability, a method for identifying a link, a method for calculating a routing, and a method for disseminating node address information. In the method of the node address information dissemination, when the network is initiated, each node in the automatically switched optical network performs a node address aggregation process and an aggregation address dissemination process, and obtains and stores the aggregation address respectively. Therefore, any node in the network may judge whether the node and another node in the network are reachable to each other, and may further calculate the routing between the source and destination nodes pair. Moreover, the present invention also may determine whether any traffic engineering link in the multi-level ASON network is an external link or an internal link.