MPLS Sub-Label Encoding for Extended Source Routes
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Solution Overview
Problem
Existing network technologies face limitations in encoding longer source routes due to constraints in the number of MPLS labels that can be added to a packet header, making it impractical for scaled-up networks with complex paths.
Innovation Solution
The method involves splitting a single MPLS label into multiple sub-labels, allowing each sub-label to represent an edge in the route, thereby enabling longer source routes by dividing the packet header into sub-segments and using these sub-labels to encode pairs or groups of edges, which can be transmitted across the network.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If multiple MPLS labels are added to encode longer source routes, then the network path encoding capability is improved, but the device complexity and hardware limitations are worsened
Solution Approach 1:
The patent divides a single 20-bit MPLS label into multiple sub-labels (e.g., two 10-bit sub-labels). Each sub-label represents a portion of the source route, allowing longer paths to be encoded without increasing the number of MPLS label stacks. This segmentation enables the encoding of up to twice as many potential hops while maintaining compatibility with existing hardware that has limitations on the number of MPLS labels per packet.
2Reliability
If MPLS labels are used to represent each edge in the path, then strict source routing is achieved, but the network scalability is limited
Solution Approach 1:
The patent transitions from using multiple MPLS label stacks (one dimension) to using sub-fields within a single MPLS label (another dimension). By utilizing the bit structure of the MPLS label (dividing the 20-bit label into sub-labels), the system can encode longer source routes without adding more label stacks, thus improving network scalability while maintaining strict source routing capability.
3Device complexity
If loose source routing is implemented to work around hardware limitations, then device complexity is reduced, but strict source routing is lost
Solution Approach 1:
By segmenting the MPLS label into sub-labels, the patent enables strict source routing to be implemented without requiring complex workarounds. Each sub-label can precisely represent an edge in the source route, allowing routers to strictly follow the encoded path while keeping the implementation relatively simple compared to loose source routing approaches.
Data Source
AI summary
Generally disclosed herein is an approach for modifying use of segment routing multiprotocol label switching (SR-MPLS) allowing an arbitrary MPLS control plane and traditional MPLS data plane to utilize a single MPLS label to represent two or more edges in a path. MPLS labels may be divided into smaller sub-labels, which together uniquely represent a pair of edges along a route. In one example, a single MPLS label may be divided into two sub-labels, the first sub-label representing a first edge, and the second sub-label representing a second edge. In this regard, longer source routes may be supported in a packet header in network designs that implement strict source routing.