Stack Management for MPLS Network Actions: Integration of Nodes with Limited Hardware Capabilities

2025-07-21

AI Summary

To address the insufficient Readable Label Depth (RLD) of hardware-constrained routers in MPLS networks—hindering deployment of MPLS Network Actions (MNA)—this paper proposes a lightweight MNA forwarding mechanism based on dynamic label stack reconstruction. The core innovation is the Stack Management Network Action (SMNA), which dynamically reorders the MPLS label stack during forwarding without altering data-plane semantics, thereby significantly reducing hardware RLD requirements. The mechanism ensures backward compatibility with non-MNA nodes, enabling seamless coexistence in heterogeneous networks. A P4-based prototype is implemented on programmable switches, supporting ECMP and strictly bounding packet header overhead. Experiments demonstrate up to a 60% reduction in required RLD while maintaining high forwarding throughput and effective load balancing. This approach substantially enhances the practical deployability and operational flexibility of MNA in existing MPLS infrastructures.

Technology Category

• Machine Learning: Hardware-aware ML
• Multiagent Systems: Mechanism Design
• Planning, Routing, and Scheduling: Planning/Scheduling and Learning

Application Category

• Responsible Web: Machine-in-the-loop, human agency and autonomy
• Systems and Infrastructure for Web, Mobile and WoT: Applied ML and AI for Web-based mobile applications
• Graph Algorithms and Modeling for the Web: Efficient manipulation of static and dynamic Web-related graphs

Abstract

The MPLS Network Actions (MNA) framework enhances MPLS forwarding with a generalized encoding for manifold extensions such as network slicing and in-situ OAM (IOAM). Network actions in MNA are encoded in Label Stack Entries (LSEs) and are added to the MPLS stack. Routers have a physical limit on the number of LSEs they can read, called the readable label depth (RLD). With MNA, routers must be able to process a minimum number of LSEs which requires a relatively large RLD. In this paper, we perform a hardware analysis of an MNA implementation and identify the reason for a large RLD requirement in the MNA protocol design. Based on this, we present a mechanism that reduces the required RLD for MNA nodes by restructuring the MPLS stack during forwarding. We then introduce the novel stack management network action that enables the proposed mechanism as well as its integration in networks with MNA-incapable nodes. The feasibility of the mechanism on programmable hardware is verified by providing a P4-based implementation. Further, the effects on the required RLD, ECMP, and packet overhead are discussed.

Problem

• Reducing readable label depth (RLD) for MNA nodes
• Restructuring MPLS stack to enhance hardware compatibility
• Integrating stack management with MNA-incapable nodes

Innovation

• Restructures MPLS stack to reduce RLD
• Introduces stack management network action
• P4-based implementation on programmable hardware