TRILL Network Frame Routing via Service VLAN Identifiers
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Solution Overview
Problem
Current TRILL networks face limitations due to the 4096 VLAN identifier constraint, which restricts the scalability and efficiency of provider bridge networks, and existing hardware does not support MAC-in-MAC encapsulation required for shortest path routing solutions like TRILL and SPPBB.
Innovation Solution
The implementation of TRILL networks using service VLAN identifiers allows edge bridges without MAC-in-MAC encapsulation support to route frames by employing service VLAN identifiers for ingress and egress bridges, enabling shortest path forwarding without the need for hardware upgrades, utilizing existing rack-mounted bridges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If TRILL networks use standard VLAN identifiers, then network routing is simplified, but the VLAN identifier limitation of 4096 restricts network scalability
Solution Approach 1:
The patent segments the VLAN identifier space by introducing a service VLAN identifier (SVLAN) that is separate from customer VLAN identifiers. This segmentation allows the network to scale beyond 4096 total VLANs by using the SVLAN as an additional dimension for identifying network segments and routing paths.
Solution Approach 2:
The patent implements a nested structure where service VLAN identifiers encapsulate customer VLAN identifiers. The frame format includes both an outer SVLAN tag and inner customer VLAN tags, creating a nested hierarchy that allows multiple layers of VLAN segmentation and routing.
2Productivity
If edge bridges implement MAC-in-MAC encapsulation for shortest path routing, then routing efficiency improves, but hardware complexity and cost increase
Solution Approach 1:
The patent extracts the MAC-in-MAC encapsulation requirement from the edge bridge hardware by implementing it in software or through protocol processing. The service VLAN identifier mechanism achieves shortest path routing without requiring hardware-level dual MAC address encapsulation capabilities.
Solution Approach 2:
The patent uses software-based processing instead of expensive hardware upgrades. Existing rack-mounted bridges can be used by implementing the service VLAN routing logic in software, avoiding the need for costly hardware that supports MAC-in-MAC encapsulation.
3Ease of manufacture
If existing rack-mounted bridges are used as edge bridges, then implementation cost is reduced, but the bridges lack MAC-in-MAC encapsulation support
Solution Approach 1:
The patent changes the operational parameters of existing bridges by introducing service VLAN identifiers that these bridges can handle with their existing hardware capabilities. The bridges operate with modified VLAN tagging parameters rather than requiring new encapsulation capabilities.
Solution Approach 2:
The service VLAN identifier mechanism provides universal compatibility with existing bridge hardware while enabling advanced TRILL network functionality. The same bridge hardware can serve multiple functions including standard VLAN bridging and TRILL edge bridge operations.
Data Source
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AI summary
Methods, apparatus, and products are disclosed for routing frames in a TRILL network using service VLAN identifiers by: receiving a frame from an ingress bridge node for transmission through the TRILL network to a destination node that connects to the TRILL network through an egress node, the received frame including a customer VLAN identifier, a service VLAN identifier uniquely assigned to the ingress bridge node, and a destination node address for the destination node, the received frame not having mac-in-mac encapsulation; adding, in dependence upon the service VLAN identifier and the destination node address, a TRILL header conforming to the TRILL protocol, the TRILL header including an ingress bridge nickname and an egress bridge nickname; and routing, to the egress bridge node through which the destination node connects to the network, the frame in dependence upon the ingress bridge nickname and the egress bridge nickname.