Scalable Approach to Dynamic SLA Negotiation Mechanism in Protected Shared Mesh Optical Networks

AbstractThis paper investigates the scalability issues concerned with the dynamic SLA negotiation mechanism proposed in the previous study. The previous work presented a dynamic service level agreement negotiation mechanism considering intra- and inter-domain communications over shared mesh optical networks which may cause heavy control overheads in a dynamic environment such as the control plane of GMPLS-based networks. In this paper, two main issues regarding the dynamic propagation of information will be analyzed: i) control overhead, and ii) propagation delay. The paper employs some alternative means of communication to reduce the overheads and resolve the possible scalability issues

PILEP: a contribution to PCE-based interdomain path computation

The process of computing routes that network traffic must follow throughout Internet has become more complex in the last years. Nowadays, this process is subject to the application of several constraints related to traffic engineering, resources management, quality of the offered services, security or robustness. The application of all these constraints has caused an increase of complexity of those nodes in charge of path computation. Sometimes, the amount of time and resources spent to compute routes is superior to resources used in the main task of these nodes: traffic classification and forwarding. PCE (Path Computation Element) architecture is being developed to diminish that problem in the context of constraint-based path computation for MPLS (Multiprotocol Label Switching). Although research work in relation to this topic is making progress quickly, there are still some unsolved aspects. As a contribution to PCE development, in this work we present a mechanism called PILEP (Procedure for Interdomain Location of External PCEs) that allows the dynamic discovery of routes computation elements in interdomain environments, making use of the existing routing protocols.Postprint (author’s final draft

PCE prototype with segment routing and BGPLS support

This project presents two contributions to the PCE implementation in Telefonica I+D: Segment Routing and the upgrade of the BGP-LS protocol to the 3rd version of the draft to support MPLS and GMPLS scenarios. Regarding the first contribution, this document is intended to assess the use of Segment Routing in centralised traffic-engineering scenarios. It will attempt to make a validation of such technology using the available IETF drafts and publications and trying, at all time, to back-up the use cases with experimental demonstrations. Moreover, the 3rd version of the BGP-LS protocol draft was implemented. This protocol opens the possibility to export the network’s topology and its Traffic Engineering parameters to external entities. The BGP-LS extensions developed enables to retrieve the TE parameters for MPLS and GMPLS networks. The development of the project was done in Telefonica R&D’s facilities within the Core Network Evolution group. The code extends Telefonica’s PCE and network protocols to support Segment Routing and the new version for BGP-LS. As such, both the PCEP and the BGP-LS protocols were enhanced with the latest IETF drafts that define the technology. Once the code was developed and debugged, a series of tests were run in order to validate that the format used followed all the proposed standards. These tests have been defined following the sections that constitute each draft in an attempt to proof the use of each protocol in the most exhaustive possible way. It is important to remark that the validation tests are done not only with Telefonica code, but also with external prestigious entities like Cisco, Telecom Italia, Centre Tecnològic Telecomunicacions Catalunya or Consorzio Nazionale Interuniversitario per le Telecomunicazioni.Ingeniería de Telecomunicació

Self-healing and SDN: bridging the gap

Achieving high programmability has become an essential aim of network research due to the ever-increasing internet traffic. Software-Defined Network (SDN) is an emerging architecture aimed to address this need. However, maintaining accurate knowledge of the network after a failure is one of the largest challenges in the SDN. Motivated by this reality, this paper focuses on the use of self-healing properties to boost the SDN robustness. This approach, unlike traditional schemes, is not based on proactively configuring multiple (and memory-intensive) backup paths in each switch or performing a reactive and time-consuming routing computation at the controller level. Instead, the control paths are quickly recovered by local switch actions and subsequently optimized by global controller knowledge. Obtained results show that the proposed approach recovers the control topology effectively in terms of time and message load over a wide range of generated networks. Consequently, scalability issues of traditional fault recovery strategies are avoided.Postprint (published version

Segment Routing: a Comprehensive Survey of Research Activities, Standardization Efforts and Implementation Results

Fixed and mobile telecom operators, enterprise network operators and cloud providers strive to face the challenging demands coming from the evolution of IP networks (e.g. huge bandwidth requirements, integration of billions of devices and millions of services in the cloud). Proposed in the early 2010s, Segment Routing (SR) architecture helps face these challenging demands, and it is currently being adopted and deployed. SR architecture is based on the concept of source routing and has interesting scalability properties, as it dramatically reduces the amount of state information to be configured in the core nodes to support complex services. SR architecture was first implemented with the MPLS dataplane and then, quite recently, with the IPv6 dataplane (SRv6). IPv6 SR architecture (SRv6) has been extended from the simple steering of packets across nodes to a general network programming approach, making it very suitable for use cases such as Service Function Chaining and Network Function Virtualization. In this paper we present a tutorial and a comprehensive survey on SR technology, analyzing standardization efforts, patents, research activities and implementation results. We start with an introduction on the motivations for Segment Routing and an overview of its evolution and standardization. Then, we provide a tutorial on Segment Routing technology, with a focus on the novel SRv6 solution. We discuss the standardization efforts and the patents providing details on the most important documents and mentioning other ongoing activities. We then thoroughly analyze research activities according to a taxonomy. We have identified 8 main categories during our analysis of the current state of play: Monitoring, Traffic Engineering, Failure Recovery, Centrally Controlled Architectures, Path Encoding, Network Programming, Performance Evaluation and Miscellaneous...Comment: SUBMITTED TO IEEE COMMUNICATIONS SURVEYS & TUTORIAL

An Open Unified Addressing System for 6G Communication Networks

With the rapid and continuous development of the Internet, it is foreseeable that current addressing schemes and fixed-length IP addresses would create further bottlenecks and limitations in realizing future 6G networking requirements, such as massive connections, resource-constrained communication, and heterogeneous hyper interconnections and guaranteeing agreement-based services and KPIs. Moreover, the locator-based addressing semantic is unsuitable for mobile and content-oriented networks. Thus, this paper proposes the Open Unified Addressing (OUA) system, a novel, flexible, multi-semantic and hierarchical addressing architecture that better supports the flexibility and extensibility of the Internet protocol framework in the context of 6G Communications. The OUA addresses several limitations in the current IP protocol and improves communication efficiency. According to the evaluation with two typical forwarding models, the results show that the OUA system has almost no impact on forwarding delay. Moreover, it can provide scalable addressing spaces and shorten the route convergence time

On security and privacy of consensus-based protocols in blockchain and smart grid

In recent times, distributed consensus protocols have received widespread attention in the area of blockchain and smart grid. Consensus algorithms aim to solve an agreement problem among a set of nodes in a distributed environment. Participants in a blockchain use consensus algorithms to agree on data blocks containing an ordered set of transactions. Similarly, agents in the smart grid employ consensus to agree on specific values (e.g., energy output, market-clearing price, control parameters) in distributed energy management protocols. This thesis focuses on the security and privacy aspects of a few popular consensus-based protocols in blockchain and smart grid. In the blockchain area, we analyze the consensus protocol of one of the most popular payment systems: Ripple. We show how the parameters chosen by the Ripple designers do not prevent the occurrence of forks in the system. Furthermore, we provide the conditions to prevent any fork in the Ripple network. In the smart grid area, we discuss the privacy issues in the Economic Dispatch (ED) optimization problem and some of its recent solutions using distributed consensus-based approaches. We analyze two state of the art consensus-based ED protocols from Yang et al. (2013) and Binetti et al. (2014). We show how these protocols leak private information about the participants. We propose privacy-preserving versions of these consensus-based ED protocols. In some cases, we also improve upon the communication cost