Improved network resilience of wireless mesh networks using MPLS and Fast Re-Routing techniques L. Bisti a , L. Lenzini a , E. Mingozzi a,⇑ , C. Vallati a , A. Erta b , U. Malesci b a Dipartimento di Ingegneria dell’Informazione, University of Pisa, Via Diotisalvi, 2, I-56122, Pisa, Italy b Fluidmesh Networks, Inc., Boston, MA, United States article info Article history: Available online 21 March 2011 Keywords: Mesh Networks MPLS Fast Re-Routing Click Modular Router abstract The performance of a wireless mesh network (WMN) can be significantly affected by node failures and medium-term time-varying phenomena in the wireless channel, which may lead to significant interruptions in packet delivery service. Because of their nature, WMNs are often deployed with an inherent degree of redundancy. In principle, this flexibility might be exploited to cope with the link failure problem by temporarily re-routing ongoing traffic on alternate paths. However, the existing routing protocols cannot be used for this purpose, since they either rely on link-state updates, which happen on a longer time scale than the phenomena under consideration, or the decisions are taken by the source node, which does not know the status on intermediate links. In this paper we present a Fast Re-Routing enabled architecture that is optimized for WMNs and allows nodes to react to local node or link failures by activating a pre-configured alternate path to reach a two-hop neighbor. The proposed scheme is enabled by label switching/stacking. Alternate paths are created automatically during the path setup phase via a lightweight protocol derived from LDP. The solution is proved to be effective through a testbed implementation. Ó 2011 Elsevier B.V. All rights reserved. 1. Introduction Wireless mesh networks (WMNs) are a mature technol- ogy nowadays and have been picked up by the industry to address a niche market in many application fields [7,8]. With regard to the service level provided by the network, the various applications have distinct critical requirements in terms of bandwidth, latency or packet delivery ratio. For instance, packet loss minimization is crucial in contexts where data loss is highly undesirable (or even not tolera- ble), such as critical sensors monitoring, real-time remote control or video surveillance. Packet loss may occur in wireless networks for several reasons and at different time scales: the wireless nature of the transmissive medium it- self leads to frequent communication errors due to exter- nal RF noise, co-location of different networks, or interference among multiple nodes transmitting at the same time. Longer interruptions in the delivery service may result from transient link failures, e.g., temporarily obstructions in the line of sight between two antennas, or from more critical ones like power loss or hardware faults at the nodes. In this paper we present a novel solution to increase the robustness of a WMN in case of communication errors and failures. Our approach is based on the availability of orthogonal data and control planes built upon the MPLS la- bel switching technology, integrated by a set of functional- ities which realize an ad-hoc FRR solution tailored to suit the inherent characteristics of these kind of networks and simplify the signaling protocols. The proposed solution is independent of any underlying routing protocol, and the main motivations behind this choice are essentially two: (i) the ability to target fast reaction times in a scale that cannot be achieved by routing protocols without 1570-8705/$ - see front matter Ó 2011 Elsevier B.V. All rights reserved. doi:10.1016/j.adhoc.2011.03.006 ⇑ Corresponding author. Tel.: +39 0502217655. E-mail addresses: luca.bisti@iet.unipi.it (L. Bisti), l.lenzini@iet.unipi.it (L. Lenzini), e.mingozzi@iet.unipi.it (E. Mingozzi), carlo.vallati@iet.unipi.it (C. Vallati), alessandro.erta@fluidmesh.com (A. Erta), umberto.malesci@ fluidmesh.com (U. Malesci). Ad Hoc Networks 9 (2011) 1448–1460 Contents lists available at ScienceDirect Ad Hoc Networks journal homepage: www.elsevier.com/locate/adhoc