Variable Length Label Allocation in MPLS Networks
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Solution Overview
Problem
Conventional Multi-Protocol Label Switching (MPLS) networks are limited by the use of 20-bit fixed format labels, which restrict flexibility and efficiency in packet encapsulation and forwarding, as they do not support labels of varying lengths, such as 40-bit labels, that could provide additional service information and context.
Innovation Solution
Network devices are configured to support and utilize labels of varying lengths, specifically 40-bit labels, by sending label request messages to indicate support for these longer labels, receiving corresponding label mappings, and appending them to packets for forwarding according to label switching protocols, allowing for more flexible service deployment and packet handling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If 20-bit fixed format labels are used in MPLS networks, then backward compatibility and simplicity are maintained, but flexibility and service information capacity are limited
Solution Approach 1:
The patent implements dynamic label length support by enabling network devices to negotiate and adapt between 20-bit and 40-bit labels based on service requirements. The system dynamically selects label formats rather than being fixed, allowing flexibility while maintaining compatibility with existing 20-bit infrastructure through conditional label processing
Solution Approach 2:
The patent changes the label length parameter from a fixed 20 bits to a variable parameter that can be 20 or 40 bits. This parameter change enables the system to carry additional service information (20 extra bits) while maintaining backward compatibility through selective parameter usage based on service type and device capability
2Loss of information
If 40-bit labels are implemented, then service information capacity and flexibility are enhanced, but device complexity and processing overhead increase
Solution Approach 1:
The patent segments the label information into different portions: the first 20 bits maintain standard MPLS functionality for basic forwarding, while the additional 20 bits in 40-bit labels carry extended service information. This segmentation allows incremental adoption and selective processing of extended information without requiring complete system redesign
Solution Approach 2:
The patent introduces capability advertisement messages as intermediaries that negotiate label format support between network devices. These intermediary messages enable devices to agree on appropriate label lengths (20 or 40 bits) before establishing label switched paths, reducing processing complexity by avoiding unnecessary 40-bit label handling when 20 bits suffice
3Adaptability or versatility
If variable label lengths are supported, then service deployment flexibility improves, but protocol complexity and device configuration difficulty increase
Solution Approach 1:
The patent implements self-service through automated capability advertisement and negotiation mechanisms. Network devices automatically advertise their label length support capabilities and negotiate appropriate label formats with peer devices, eliminating the need for manual configuration of label lengths and reducing operational complexity while maintaining service deployment flexibility
Data Source
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AI summary
In one example, a network device receives a packet to be forwarded according to a label switching protocol, determines a service to be performed on the packet by a service network device, sends a label request message to the service network device, wherein the label request message indicates support for labels having a particular length, wherein the particular length is larger than twenty bits (e.g., forty bits), and wherein the label request message specifies the service to be performed on the packet, receives, in response to the label request message, a label mapping message defining a label of the particular length, appends the label to the packet to form a Multi-Protocol Label Switching (MPLS)-encapsulated packet, and forwards the MPLS-encapsulated packet according to the label switching protocol.