Hierarchical Ethernet Aggregation Nodes for IS-IS Scalability
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Solution Overview
Problem
Current telecommunications systems using link state routing protocols like IS-IS or OSPF face scalability issues due to the large number of adjacencies required for managing per-VLAN instances in shortest path bridging, leading to complexity and potential limitations in network scale.
Innovation Solution
The system employs a hierarchical organization using aggregation nodes and link state routing protocols like IS-IS, PNNI, or OSPF, combined with Q-in-Q encapsulation to reduce the number of adjacencies and complexity by forming a natural VLAN hierarchy, allowing summarized information to be shared across networks, thereby reducing the number of instances and adjacencies needed in intermediate bridges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If per-VLAN instances of link state routing protocol are used for shortest path bridging, then forwarding path determination is simplified, but the number of adjacencies increases dramatically
Solution Approach 1:
The patent segments the network into hierarchical levels (Level 1 and Level 2) where Level 1 represents local area networks and Level 2 represents the backbone network. This segmentation allows link state routing instances to be confined to specific levels, reducing the total number of adjacencies while maintaining per-VLAN forwarding capabilities within each segment.
Solution Approach 2:
The patent introduces a hierarchical dimension to the network architecture, organizing bridges and VLANs across multiple levels. This dimensional change allows the system to maintain detailed per-VLAN routing information locally at Level 1 while using aggregated Level 2 routing for inter-network communication, thereby reducing overall adjacency complexity.
2Adaptability or versatility
If the network scale is expanded to support many VLANs, then network versatility increases, but the number of adjacencies and complexity increases
Solution Approach 1:
By dividing the network into hierarchical levels, the patent enables each level to support a manageable number of VLANs independently. Level 1 networks can support local VLANs while Level 2 provides backbone connectivity, allowing the overall system to support many VLANs without requiring all bridges to maintain adjacencies to all VLANs.
Solution Approach 2:
Level 2 backbone bridges act as intermediaries between different Level 1 networks. These intermediary bridges aggregate routing information and provide connectivity between multiple Level 1 networks, enabling VLANs to span across networks without requiring direct adjacencies between all edge bridges.
3Measurement precision
If edge bridges maintain adjacencies to all VLANs, then forwarding accuracy is improved, but memory and processing requirements increase
Solution Approach 1:
The patent applies local quality by enabling edge bridges to maintain detailed per-VLAN forwarding information only for their local Level 1 network, while relying on hierarchical routing for remote VLANs. This localized approach maintains forwarding accuracy for local traffic while reducing resource requirements by not maintaining global VLAN adjacency information at every bridge.
Data Source
AI summary
A first aggregation node in communication with the first network and the second network, the source node and internal nodes of the first network only having knowledge of each other and of the first aggregation node. The system includes a second aggregate node in communication with the second network and the third network, the internal nodes of the second network only having knowledge of each other and the first and second aggregate nodes, the destination node and the internal nodes of the third network only having knowledge of each other and the second aggregation node, the first and second aggregation nodes only having knowledge of each other, the destination node receiving the data from the source node using a link state routing protocol and shortest path bridging through the first second and third networks and the first and second aggregation nodes.