Path computation in multi-layer networks: Complexity and algorithms

TL;DR

This paper addresses the complex problem of path computation in multi-layer networks with protocol encapsulation and conversion, proposing new algorithms that improve efficiency and scalability over existing methods.

Contribution

It introduces novel algorithms for path computation in multi-layer networks considering protocol encapsulation, conversion, and QoS constraints, with analysis of their complexity and performance.

Findings

Algorithms outperform previous solutions in real topology tests.

Proposed methods handle various QoS constraints effectively.

Scalability and complexity are thoroughly analyzed.

Abstract

Carrier-grade networks comprise several layers where different protocols coexist. Nowadays, most of these networks have different control planes to manage routing on different layers, leading to a suboptimal use of the network resources and additional operational costs. However, some routers are able to encapsulate, decapsulate and convert protocols and act as a liaison between these layers. A unified control plane would be useful to optimize the use of the network resources and automate the routing configurations. Software-Defined Networking (SDN) based architectures, such as OpenFlow, offer a chance to design such a control plane. One of the most important problems to deal with in this design is the path computation process. Classical path computation algorithms cannot resolve the problem as they do not take into account encapsulations and conversions of protocols. In this paper, we propose algorithms to solve this problem and study several cases: Path computation without bandwidth constraint, under bandwidth constraint and under other Quality of Service constraints. We study the complexity and the scalability of our algorithms and evaluate their performances on real topologies. The results show that they outperform the previous ones proposed in the literature.